Non-small cell lung cancer (8th edition of the TNM classification for lung cancer IASLC). All about lung cancer at different stages of its development International classification of lung cancer

deaths from lung cancer than women taking placebo. Among women who smoked (former and current smokers), 3.4% of those who took the hormones died from lung cancer, compared with 2.3% of women who took a placebo.

With the experience of smoking tobacco, the likelihood of developing lung cancer in a person increases. If a person stops smoking, this likelihood steadily decreases as damaged lungs are repaired and polluting particles are gradually eliminated. In addition, there is evidence that lung cancer in never smokers has a better prognosis than in smokers, and therefore patients who smoke moment of diagnosis have lower survival rates than those who quit smoking long ago.

Passive smoking(inhalation of tobacco smoke from another smoker) is a cause of lung cancer in non-smokers. Studies in the US, Europe, UK and Australia have shown a significant increase in relative risk among those exposed to secondhand smoke. Recent studies have shown that the smoke exhaled by a smoker is more dangerous than inhaling it directly from a cigarette. 10-15% of lung cancer patients have never smoked.

Radon is a colorless and odorless gas formed by the decay of radioactive radium, which in turn is a product of the decay of uranium present in the Earth's crust. Radioactive radiation can damage genetic material, causing mutations that sometimes lead to the development of malignant tumors. Exposure to radon is the second cause of lung cancer in the general population, after smoking, with an increase in risk of 8% to 16% for every 100 Bq/m³ increase in radon concentration. The concentration of radon in the atmosphere depends on the area and the composition of the underlying soils and rocks. For example, in areas such as Cornwall in the UK (where there are granite reserves), radon

A big problem, and buildings must be well ventilated to reduce radon concentrations.

Rusty bodies due to asbestosis. Hematoxylin and eosin staining

2.4. Viruses

Viruses are known to cause lung cancer in animals, and recent evidence suggests they can cause lung cancer in humans. These viruses include human papilloma virus, JC virus , monkey virus 40(SV40), BK virus and cytomegalovirus. These viruses can influence the cell cycle and suppress apoptosis, promoting uncontrolled cell division.

2.5. Dust particles

Research from the American Cancer Society has found a direct link between exposure to dust particles and lung cancer. For example, if the concentration of dust in the air increases by only 1%, the risk of developing lung cancer increases by 14%. In addition, it has been established that the size of dust particles is important, since ultrafine particles are able to penetrate into the deep layers of the lung.

	3. Classification of lung cancer
2.3. Asbestosis	by stages
Asbestos can cause various lung diseases	According to the domestic classification, lung cancer
diseases, including lung cancer. There is mutual	is divided into the following stages:
the effect of tobacco smoking and asbestosis on the	Stage I - tumor up to 3 cm at its largest
incidence of lung cancer. Asbestosis can also
cause pleural cancer called mesothelioma (co-	dimension, located in one segment of the lungs
which should be differentiated from lung cancer).	whom or within the segmental bronchus.

3.1

There are no metastases.

Stage II - tumor up to 6 cm in greatest dimension, located in one lung segment or within a segmental bronchus. Single metastases are observed in the pulmonary and bronchopulmonary lymph nodes.

Stage III - a tumor larger than 6 cm with transition to the adjacent lobe of the lung or invasion of the neighboring bronchus or main bronchus. Metastases are found in bifurcation, tracheobronchial, paratracheal lymph nodes.

Stage IV - the tumor extends beyond the lung with spread to neighboring organs and extensive local and distant metastases, followed by cancerous pleurisy.

According to TNM classifications, tumors are determined by:

T - primary tumor:

Tx - there is insufficient data to assess the primary tumor, or tumor cells are found only in sputum or bronchial lavage water, but not detected by bronchoscopy and/or other methods

T0 - the primary tumor is not detected

Tis - non-invasive cancer (carcinoma in situ)

Tl - tumor up to 3 cm in greatest dimension, surrounded by lung tissue or visceral pleura without invasion proximal to the lobar bronchus during bronchoscopy (the main bronchus is not affected)

T2 - a tumor more than 3 cm in greatest dimension or a tumor of any size, growing into the visceral pleura, or accompanied by atelectasis, or obstructive pneumonia, extending to the root of the lung, but not involving the entire lung; According to bronchoscopy, the proximal edge of the tumor is located at least 2 cm from the carina.

T3 - a tumor of any size, extending to the chest wall (including a tumor of the superior sulcus), diaphragm, mediastinal pleura, pericardium; a tumor that does not reach the carina by less than 2 cm, but without involving the carina, or a tumor with concomitant atelectasis or obstructive pneumonia of the entire lung.

T4 - a tumor of any size directly extending to the mediastinum, heart, large vessels, trachea, esophagus, vertebral bodies, carina (separate tumor nodes in the same lobe or a tumor with malignant pleural effusion)

N - regional lymph nodes

Nx - insufficient data to assess the condition of regional lymph nodes

N0 - no signs of metastatic lesions of regional lymph nodes

N1 - there is damage to the peribronchial and/or lymph nodes of the lung root on the affected side, including direct spread of the tumor to the lymph nodes.

N2 - there is damage to the mediastinal lymph nodes on the affected side or bifurcation lymph nodes.

N3 - damage to the lymph nodes of the mediastinum or the root of the lung on the opposite side: prescalal or supraclavicular nodes on the affected side or on the opposite side

M - distant metastases

Mx - insufficient data to determine distant metastases

M0 - no signs of distant metastases

M1 - there are signs of distant metastases, including individual tumor nodes in another lobe

G - histopathological grading

Gx - degree of cell differentiation cannot be assessed

G1 - high degree of differentiation

G2 - moderate degree of differentiation

G3 - poorly differentiated tumor

G4 - undifferentiated tumor

3.1. Histological classification of lung cancer

According to histological classification, lung cancer is divided into the following types:

I. Squamous cell (epidermoid) carcinoma

a) highly differentiated

b) moderately differentiated

c) poorly differentiated

5589 0

The prevalence of the tumor process is one of the main factors determining the choice of treatment method, the extent of surgical intervention and prognosis.

The stage of the disease depends on the size and extent of the primary tumor, its relationship to surrounding organs and tissues, as well as metastasis - the location and number of metastases.

Various combinations of factors characterizing the prevalence of the tumor process make it possible to distinguish between the stages of the disease.

Classification of lung cancer by stages makes it possible to evaluate the effectiveness of organizational measures to identify this disease and ensure the exchange of information on the results of treating patients with different methods.

The classification of lung cancer by stage, adopted in the USSR and recommended for use in 1985, currently cannot satisfy clinicians, since it contains a number of subjective coding criteria such as “ingrowth... in a limited area”, “removable and unremovable metastases in the lymph nodes” mediastinum”, “sprouting over a significant extent”, which does not allow us to unambiguously judge the stage and unify treatment tactics.

Even stage IV includes both locoregional and generalized tumor process. This classification, in our opinion, is significantly inferior to international ones both from a scientific and practical point of view.

Progress in the development of diagnostic methods, the accumulation of clinical material, and new therapeutic options lead to a revision of established ideas. Thus, the International Classification of Lung Cancer according to the TNM system (1968), based primarily on long-term results of treatment, was revised 4 times - in 1974, 1978, 1986 and 1997.

The fundamental differences of the latest classification (1986), widely recommended by the International Union Against Cancer, include the separation of pre-invasive cancer (Tis), as well as microinvasive cancer and its classification into the T1 category, regardless of location, specific pleurisy - to T4, metastases in the supraclavicular lymph nodes - to N3. Such a rubric is more consistent with ideas about the meaning of the nature and extent of the tumor.

The proposed gradations by stages in the TNM system are quite clearly defined and suggest the identification of groups of patients who are indicated for surgical or conservative antitumor treatment (in relation to non-small cell forms of lung cancer). This gives reason to currently give preference to this particular classification and contributes to the international integration of scientific research.

Until recently, we used this International Classification of Lung Cancer according to the TNM system, fourth revision, published by a special committee of the International Union Against Cancer in 1986. The addition of numbers to the symbols T, N and M indicates the different anatomical extent of the tumor process.

The rule of the TNM system is to use two classifications:

Clinical classification TNM (or c TNM), based on the results of clinical, radiological, endoscopic and other studies. The symbols T, N and M are determined before the start of treatment, as well as taking into account additional data obtained from the use of surgical diagnostic methods.

Post-surgical, pathohistological classification (or pTNM), which is based on information established before the start of treatment and supplemented or modified by data obtained during surgery and the study of the surgical specimen.

International classification of lung cancer according to the TNM system (1986)

T - primary tumor;
TC - there is insufficient data to assess the primary tumor, the presence of which is proven only on the basis of detection of cancer cells in sputum or bronchial washings; the tumor is not visualized by x-ray and bronchoscopy;
T0 - the primary tumor is not determined;

Tis - intraepithelial (preinvasive) cancer (carcinoma in situ);
T1 - microinvasive cancer, a tumor up to 3 cm in greatest dimension, surrounded by pulmonary tissue or visceral pleura, without affecting the latter and without bronchoscopic signs of invasion proximal to the lobar bronchus;
T2 - tumor more than 3 cm in greatest dimension, or extending into the main bronchus at least 2 cm from the carina of the trachea bifurcation (carina trachealis), or growing into the visceral pleura, or accompanied by atelectasis, but not the entire lung;

T3 Tumor of any size directly extending into the chest wall (including apical tumor), diaphragm, mediastinal pleura, pericardium, or tumor extending into the main bronchus less than 2 cm from the carina of the trachea, but without involvement of the latter, or tumor with atelectasis or pneumonia of the entire lung;
T4 - tumor of any size, directly extending to the mediastinum, heart (myocardium), great vessels (aorta, common trunk pulmonary artery, superior vena cava), trachea, esophagus, vertebral body, carina of the trachea, or tumor with malignant cytologically confirmed pleural effusion;
N - regional lymph nodes;

NX - regional lymph nodes cannot be assessed;
N0 - no metastases in regional lymph nodes;
N1 - metastatic lesion of the intrapulmonary, ipsilateral bronchopulmonary and/or lymph nodes of the lung root, including their involvement through direct spread of the tumor itself;

N2 - metastatic lesion of the ipsilateral mediastinal and/or bifurcation lymph nodes;
N3 - damage to the contralateral mediastinal and/or hilar lymph nodes, prescale and/or supraclavicular lymph nodes on the affected side or the opposite side;
M - distant metastases;

MX - distant metastases cannot be assessed;
MO - no distant metastases;
Ml - distant metastases are present.

PUL - lung;
PER - abdominal cavity;
MAR - bone marrow;
BRA - brain;
OSS - bones;
SKI - leather;
PLE - pleura;
LYM - lymph nodes;
ADP - kidneys;
HEP - liver;
OTN - others.

PTNM - post-surgical pathohistological classification

The requirements for determining the categories pT, pN, pM are similar to those for determining the categories T, N, M.

G - histopathological grading:

GX - the degree of cell differentiation cannot be assessed;
G1 - high degree of differentiation;
G2 - moderate degree of differentiation;
G3 - poorly differentiated tumor;
G4 - undifferentiated tumor.

R-classification:

RX - the presence of residual tumor cannot be assessed;
R0 - no residual tumor;
R1 - microscopically detectable residual tumor;
R2 - macroscopically detectable residual tumor.

Recognizing the importance and convenience of the International Classification, a number of its shortcomings should be noted. For example, symbol N2 is not specific enough, since it determines the state of all mediastinal lymph nodes - upper and lower (bifurcation) tracheobronchial, paratracheal, anterior mediastinum, etc.

Meanwhile, it is important to know which and how many of the listed lymph nodes contain metastases. As is known, the prognosis of treatment depends on this.

This classification does not provide for situations that often arise in practice when there are two or more peripheral nodes in a lobe or lung (multi-nodular form of bronchioloalveolar cancer, lymphoma), pericardial effusion, involvement of the phrenic and recurrent nerves, etc. are not classified.

In this regard, in 1987 the International Society for Research on Cancer (UICC) and in 1988 the American Committee (AJCC) proposed the following additions to this classification (Mountain C.F. et al., 1993).

I. Multiple nodes in one lung

T2 - if there is a second node in one lobe at T1;
T3 - if there is a second node in one lobe at T2;
T4 - multiple (more than 2) nodes in one lobe; if at T3 there is a node in the same lobe;
M1 - presence of a node in another lobe.

Grouping of lung cancer by stages, according to the International Classification according to the TNM system (1986)

II. Large vessel involvement

T3 - damage to the pulmonary arteries and veins extrapericardially;
T4 - damage to the aorta, the main branch of the pulmonary artery, intrapericardial segments of the pulmonary artery and veins, the superior vena cava with compression syndrome of the esophagus, trachea.

III. Involvement of the phrenic and recurrent nerves

T3 - germination of the primary tumor or metastases into the phrenic nerve;
T4 - germination of the primary tumor or metastases into the recurrent nerve.

IV. Pericardial effusion

T4 - tumor cells in the pericardial fluid. The absence of tumor cells in the fluid obtained from two or more punctures and its non-hemorrhagic nature are not taken into account when determining the symbol.

V. Tumor nodules on or outside the parietal pleura

T4 - tumor nodules on the parietal pleura;
M1 - tumor nodules on the chest wall or diaphragm, but outside the parietal pleura.

VI. Bronchioloalveolar carcinoma (BAR)

In 1997, the International Union Against Cancer proposed a new International Classification of Lung Cancer according to the TNM system, fifth revision, which was published under the editorship of L.H. Sobin and Ch. Wittekind.

The characteristics of the T, N and M symbols have not undergone significant changes, except:

T4 - separate (second) tumor node in the same lobe;
M1 - single tumor nodes in different lobes (ipsilateral and contralateral);
pNO - histological examination of the root and mediastinal lymphadenectomy surgical specimen should include the study of 6 lymph nodes or more. The grouping by stages has undergone significant changes.

Until recently, for small cell lung cancer, the systematization proposed in 1973 by the Veteran's Administration Lung Cancer Study Group was used:

Localized process - damage to the hemithorax, ipsilateral median and supraclavicular lymph nodes, contralateral root nodes, specific
exudative pleurisy on the affected side;
a common process is damage to both lungs and metastases to distant organs.

Subsequently, a correction was made to this systematization, which was of little use for practice. G. Abrams et al. (1988) proposed that lesions of the contralateral root lymph nodes be classified as a “common process”, and R. Stahcl et al. (1989), K.S. Albain et al. (1990) - exclude ipsilateral pleurisy from the “localized process” category.

Rice. 2.49. Lung cancer stages IA (a) and IB (b) (scheme).

Rice. 2.50. Lung cancer stages IIA (a) and IIB (b, c) (scheme).

Rice. 2.51. Lung cancer stage IIIA (a, b) (diagram).

Rice. 2.52. Lung cancer stage IIIB (a, 6) (scheme).

Meanwhile, long-term research carried out at the Moscow Research Institute named after. P.A. Herzen, showed that small cell lung cancer also has a locoregioparous stage of development, at which surgical treatment with adjuvant polychemotherapy is justified (Trachtenberg A.H. et al., 1987, 1992).

Other domestic and foreign thoracic surgeons and oncologists came to this conclusion (Zharkov V. et al., 1994; Meyer G.A., 1986; Naruke T. et al., 1988; Karrer K. et al., 1989; Ginsberg R.G., 1989; Shepherd F.A. et al., 1991, 1993; Jackevicus A. el al., 1995).

The use of the International Classification according to the TNM system for small cell lung cancer allows us to objectively judge the degree of spread of the primary tumor and the nature of metastasis to the lymph nodes and organs, which makes it possible to obtain a more complete understanding of the contingent of treated patients and the characteristics of the course of its various histological types.

There is no generally accepted systematization in the literature according to the stages of primary malignant non-epithelial lung tumors. This allowed us, based on the study of prognosis factors in a large group of patients, to use the modified International Classification of Lung Cancer according to the TNM system for sarcomas.

The basis for systematization by stages of most variants of sarcomas is the size of the primary tumor, the number of tumor nodes, relationship to neighboring organs and structures, distribution of the bronchi, the presence and localization of metastases in the intrathoracic lymph nodes and/or distant organs.

Stages of lung sarcoma

Stage I- solitary tumor node or infiltrate up to 3 cm in greatest dimension with a peripheral clinical and anatomical form; tumor of the segmental and/or lobar bronchus with a central clinical and anatomical form; absence of regional metastases.

Stage II- solitary tumor node or infiltrate more than 3 cm, but less than 6 cm in greatest dimension, growing or not involving the visceral pleura in the peripheral form; the tumor affects the main bronchus, but no closer than 2 cm to the carina in the central form; metastases in the pulmonary, bronchopulmonary and ipsilateral root lymph nodes.

IIIA stage- tumor node or infiltrate more than 6 cm in greatest dimension or any size, growing into the mediastinal pleura, chest wall, pericardium, diaphragm in the peripheral form; the tumor affects the main bronchus with a central clinical and anatomical form at a distance of less than 2 cm from the carina; metastases in the ipsilateral mediastinal lymph nodes.

IIIB stage- a tumor node or infiltrate of any size, growing into the tissue of the mediastinum, aorta, common trunk of the pulmonary artery, superior vena cava, myocardium, esophagus, trachea, opposite main bronchus; metastases in the contralateral mediastinal and/or root, supraclavicular lymph nodes; multiple nodes or infiltrates in the lung; specific pleurisy.

IV stage- a tumor node or infiltrate of any size, the presence or absence of damage to the intrathoracic lymph nodes, but with metastases in distant organs; multinodular form of the disease or multiple infiltrates in one lobe or in several lobes of one or two lungs.

Since the degree of tumor differentiation in sarcoma is an independent prognostic factor, when the stage is finally established, category G should be added, which determines further treatment tactics after surgery.

For example, if surgery is sufficient for T2G1NIМ0, then adjuvant antitumor therapy is also indicated for T2G3N1M0. Clinical observations have shown that the degree of tumor differentiation in sarcomas is significant when its size is more than 3 cm in its greatest dimension.

In this regard, we consider it extremely important to propose a practically significant grouping of lung sarcomas according to stages, taking into account the post-surgical (pTNM) histological grading of the tumor (G).

After histological confirmation of malignant non-Hodgkin's lymphoma of the lung, it is necessary to examine the patient to exclude extrathoracic manifestations of the disease.

After this, staging is carried out according to the Ann Arbor classification by stages (Carbone P. et al., 1971; L'Hoste R. et al., 1984):

Stage I E - damage to the lung only;
Stage II 1E - damage to the lung and root lymph nodes;
Stage II 2E - damage to the lung and central lymph nodes;
Stage II 2EW - damage to the lung with involvement of the chest wall and diaphragm.

It is also extremely important to divide non-Hodgkin's lymphomas of the lung, according to the International Working Classification and the Non-Hodgkin's Lymphoma Pathologic Classification Project into lymphomas consisting of small or large cells, which determines the prognosis and choice of treatment tactics.

Carcinoid tumors are classified according to the extent of the process as

Lung cancer is a fairly common disease among the general population in the world. The peculiarities of its spread are due to smoking, the release of toxic and carcinogenic substances into the environment, harmful working conditions and better development of diagnostic methods at this stage of life.

It must be said that this condition is characterized by high secrecy, being able to masquerade as various other diseases and is often determined by chance or during a more detailed diagnosis of another disease. Like most oncological diseases, lung cancer has a large number of varieties, which are divided according to their clinical and pathomorphological properties.

General principles of classification

Lung cancer can be classified according to the following criteria:

1. Anatomically.
2. According to TNM classification.
3. According to morphological characteristics.

The anatomical classification of lung cancer includes the principles of distribution of cancer according to the structures that are affected by the oncological process. According to this classification, there are:

1. Central lung cancer.
2. Peripheral lung cancer.

TNM classification involves classification by tumor size (T score), presence/absence of lymph node involvement (N) and presence/absence of metastases (M score). The morphological classification includes varieties of the tumor process, where each is characterized by its own pathomorphological features. There is also a classification of oncological lesions of the lungs according to the degree of spread of the process:

1. Local distribution.
2. Lymphogenic.
3. Hematogenous.
4. Pleurogenic.

In addition, certain forms of lung cancer (for example, sarcoma) may be classified according to stages.

Anatomical classification

This technique is based on the principles of classifying the tumor process according to anatomical location and the nature of tumor growth in relation to the bronchus.

As already written above, a distinction is made between the central form (bronchogenic) and the peripheral form. However, according to the anatomical classification according to Savitsky, atypical forms are also added to these 2 varieties. In turn, each of the above forms is divided into its own subspecies.

Central or bronchogenic lung cancer usually occurs in the large bronchi of the lungs. It is divided into: endobronchial cancer, exobronchial and branched cancer. The difference between these varieties is based on the growth pattern of the tumor process. With endobronchial cancer, the tumor grows into the lumen of the bronchus and has the appearance of a polyp with a tuberous surface. Exobronchial cancer is characterized by growth in the thickness of the lung tissue, which leads to long-term preserved patency of the affected bronchus. Peribronchial cancer forms a kind of “muff” of atypical tissue around the affected bronchus and spreads in its direction. This type leads to a uniform narrowing of the bronchial lumen.

Peripheral cancer affects either the lung parenchyma or the subsegmental branches of the bronchi. It includes:

1. “Round” form of peripheral cancer.
2. Pneumonia-like tumor.
3. Pancoast cancer (apex of the lung).
4. Bronchoalveolar cancer.

The round shape is its most common type (about 70-80% of cases of peripheral lung cancer) and is located in the lung parenchyma. Pneumonia-like lung cancer occurs in 3-5% of cases and looks like an infiltrate without clear boundaries, located in the pulmonary parenchyma. Bronchoalveolar lung cancer is a well-differentiated tumor and spreads intra-alveolarly, using the alveoli themselves as stroma. Atypical forms of lung tumors are mainly due to the nature of metastasis. The most common type of this form is mediastinal lung cancer, which is multiple tumor metastasis to the intrathoracic lymph nodes in the absence of an identified primary cancer focus.

TNM classification

This classification was first presented in 1968 and is periodically revised and edited. At the moment there is a 7th edition of this classification.

As mentioned above, this classification includes three main principles: tumor size (T, tumor), lymph node involvement (N, nodulus) and metastasis (M, metastases).

Typically, the following degrees of classification are distinguished:

By tumor size:

• T0: signs of the primary tumor are not determined;
• T1: tumor less than 3 centimeters in size, without visible germination or bronchial lesions;
• T2: tumor size more than 3 centimeters or the presence of a tumor of any size with invasion into the visceral pleura;
• T3: the tumor can be of any size with the condition that it spreads to the diaphragm, chest wall, mediastinal side of the pleura;
• T4: tumor of any size with significant spread into the tissues and structures of the body + confirmed malignant nature of the pleural effusion.

By damage to the lymph nodes:

• N0 there are no metastases in the regional lymph nodes;
• N1 involves intrapulmonary, pulmonary, bronchopulmonary lymph nodes or hilar lymph nodes;
• N2 damage to the lymph nodes of the mediastinal basin or bifurcation lymph nodes;
• N3 addition to the existing damage to the lymph nodes, enlargement of the supraclavicular lymph nodes, mediastinal and hilar lymph nodes.

Classification taking into account metastatic lesions of the lungs:

• M0 - no distant metastases;
• M1, signs of the presence of distant metastases are determined.

Pathomorphological classification

This technique makes it possible to evaluate the cellular structure of the tumor and its individual physiological principles of functioning. This classification is needed in order to choose the right method of influencing a particular type of tumor in order to treat the patient.

According to pathomorphological features, the following are distinguished:

1. Large cell lung cancer.
2. Lung adenocarcinoma.
3. Squamous cell carcinoma.
4. Small cell cancer.
5. Solid lung cancers.
6. Cancer affecting the bronchial glands.
7. Undifferentiated lung cancer.

A tumor with a large cell structure is a cancer in which its cells are large, clearly visible in a microscope, in size, cytoplasm and pronounced size. This cell lung cancer can be divided into 5 more subcategories, among which the most common are:

• giant cell form;
• clear cell form.

The giant cell type of the disease is a tumor with cells of giant, bizarre shapes with a large number of nuclei. In the clear cell form, cells have a characteristic appearance with a light, “foamy” cytoplasm.

Adenocarcinoma affects epithelial cells. Its structures are capable of producing mucus and forming structures of various shapes. Due to the predominant damage to the cells of the glandular layer of the epithelium, this type is also known as glandular lung cancer. This type of tumor can have varying degrees of differentiation of its structures, and therefore both types of highly differentiated adenocarcinoma and its poorly differentiated varieties are distinguished. It must be said that the degree of differentiation has an important influence on the nature of the tumor process and the course of the disease itself. Thus, low-differentiated forms are more aggressive and more difficult to treat, while highly differentiated forms, in turn, are more susceptible to treatment.

Squamous cell carcinoma also belongs to the group of tumor processes that originate from epithelial cells. Tumor cells look like peculiar “spikes”. This type has its own peculiarity - its cells are capable of producing keratin, and therefore peculiar “growths” or “pearls” are formed, which is a hallmark of squamous cell carcinoma. It is thanks to such characteristic growths that squamous cell carcinoma also received the name “keratinizing” or “pearl cancer.”

The small cell form is characterized by the presence in its structure of small sized cells of various shapes. Usually there are 3 subspecies:

1. "Oat cell."
2. From intermediate type cells.
3. Combined.

The group of solid lung cancers is characterized by the arrangement of their structures in the form of “strands” or trabeculae, separated from each other by connective tissue. This type also refers to low-grade tumor processes.

The pathomorphological subgroup of the classification of pulmonary tumors can also include such a form as neuroendocrine lung cancer. This type is quite rare compared to other types of lung tumors and is characterized by slow growth. A neuroendocrine tumor is based on the initiation of tumor changes in a special type of cell - neuroendocrine. These cells have the ability to synthesize various proteins or hormones and are distributed throughout the human body. They are also known as the APUD system or diffuse neuroendocrine system.

Under the influence of various reasons, the natural growth and aging programs in these cells are disrupted and the cell begins to divide uncontrollably and becomes tumorous.

Despite the fact that neuroendocrine tumor processes spread rather slowly throughout the body, they are included in the list of diseases that require close attention of medical personnel. The reason for this is that these tumors have practically no characteristic clinical signs and are therefore difficult to diagnose in the early stages, as a result of which the patient develops inoperable lung cancer.

According to their classification, they distinguish:

• Carcinoid neuroendocrine tumors of the lung.
• Small cell forms.
• Large cell forms.

Neuroendocrine pulmonary tumors also have varying degrees of differentiation and malignancy. The degree of malignancy is determined by the number of divisions of the tumor cell (mitosis) and its ability to grow (proliferate). The indicator of the ability of a malignant cell to divide is called G, and the indicator of the proliferative activity of the tumor is Ki-67.

According to these indicators, 3 degrees of malignancy of a neuroendocrine tumor are determined:

1st degree, or G1, where the G and Ki-67 index is less than 2 (that is, the tumor cell is capable of making less than 2 divisions).
2nd degree or G2, where the number of mitoses is from 2 to 20, and the proliferation rate is from 3 to 20.
3rd degree or G3, at which the cell is capable of performing more than 20 divisions. The proliferation index at this stage is also above 20.

Diagnosis of neuroendocrine tumors of the lungs involves the use of radiation methods (CT, MRI, plain radiography of the chest organs), examination of sputum for atypical cells. There are also specific methods aimed at identifying the neuroendocrine characteristics of the process. Most often, 2 methods are used for this:

1. Electron microscopy of tumor biopsy.
2. Determination of immunological markers.

Using an electron microscope, it is possible to see a characteristic “granularity” in tumor cells, which is neuroendocrine granules, characteristic only of cells of the APUD system. Immunological or "neuroendocrine markers" are usually determined using immunohistochemistry. This method involves treating sections of the material under study with special antibodies to the substance of interest. Typically, for neuroendocrine tumors, such substances are synaptophysin and chromogranin-A.

Lung cancer - the prevalence of this disease over the past decades has increased faster than malignancies of other organs. At the beginning of the last century, only a few dozen cases of the disease were described, and at the beginning of this century the disease is the most frequently diagnosed malignant tumor.

Correct classification of lung cancer makes it possible to get an idea of ​​the tumor itself, its growth and size, location and extent of spread. Based on the characteristics of a malignant neoplasm, it is possible to predict the course of the disease and the results of treatment. Treatment tactics depend on the stage of the disease. Today they distinguish:

• histological classification
• clinical and anatomical
• International classification according to the TNM system

Histological classification

Histological classification is decisive in prognosis and treatment. Depending on the elements of the bronchial epithelium, the following types of lung cancer are distinguished:

• Squamous cell is the most common form, occurring in 50-60% of patients, 30 times more often in men. It mainly affects long-term smokers. Most tumors are localized in the central regions, which negatively affects diagnosis. Primary detection of a tumor occurs mainly when the symptoms are pronounced or there are complications.
• Small cell cancer (adenocarcinoma, glandular) makes up 20-25% of all lung tumors, affects women 2 times more often than men, and is localized in the peripheral parts of the lungs in 80% of cases. The tumor grows slowly and its size may remain unchanged for several months. However, this tumor is one of the most aggressive.
• Large cell - so called because of the large round cells that are clearly visible under a microscope. There is another name - undifferentiated carcinoma.
• Mixed - squamous cell and adenocarcinoma, adenocarcinoma and small cell, etc.

Classification by localization

No less important is the clinical and anatomical classification, which also determines the choice of treatment plan. According to it, they distinguish:

• central cancer - makes up 65% of all lung tumors, affects large bronchi (segmental, lobar, main). The ratio of newly discovered central to peripheral lesions is 2:1. The right lung is affected more often.
• peripheral – affects smaller bronchi
• atypical

These malignant tumors vary in location, symptoms and clinical manifestations.

The growth characteristics of a malignant tumor are also of particular importance. A tumor spreading into the lumen of the bronchus (exophytic cancer) creates a threat in terms of obstruction, which will lead to blockage of the lumen and pneumonia. A tumor with endophytic growth does not create obstacles to bronchial patency for a long time. Peribronchial growth also occurs, in which the tissue is located around the bronchus.

International classification TNM

The TNM classification, developed by the International Union Against Cancer, is used throughout the world. It is used to determine the spread of the tumor and the prognosis of treatment.

• T – tumor size and degree of invasion into surrounding tissues,
• N – presence of affected lymph nodes
• M – presence or absence of metastases in other organs

According to the TNM classification, there are 4 degrees of lung cancer.

• I degree – the tumor is small, the lymph nodes and pleura are not affected
• Stage II – tumor 3-5 cm, there are metastases to the bronchial lymph nodes
• IIIA degree - the tumor can be of any size, the pleura, chest wall are involved in the process, there are metastases to the bronchial lymph nodes or mediastinal nodes on the opposite side
• IIIB degree – the tumor affects the mediastinal organs
• IV degree – there are metastases on the other lung, metastasis to distant organs is observed

Forecast

Depending on the stage of the disease, the treatment prognosis varies. has the best result, but almost 2/3 of patients are diagnosed with a stage II-III tumor upon initial treatment. The prognosis in this case is not so optimistic; The presence of metastases is of great importance, the spread of which to other organs allows only palliative treatment. However, in the absence of metastasis, there is a chance of success with radical surgery. When the last stage of the disease is diagnosed, 80% of patients die within the first year, and only 1% have a chance to live more than 5 years.

The classification of lung cancer is based on several principles. The division is based on the histological structure, macroscopic localization, international TNM standards and stage of the disease.

The most important way for doctors to divide a disease is histologically. Each tumor consists of cells of different origin, this determines all its properties.

Lung cancer may be one of the following:

1. Squamous cell is the most common type of disease. It is more common in males because it is directly related to smoking. A constant inflammatory process and hot smoke in the bronchi provoke cell division in which mutations occur. Most often, such tumors are localized in the root of the lung, and therefore have a severe clinical picture.


2. Small cell carcinoma, or adenocarcinoma, is a rarer form. Has genetic mechanisms of development. Women are more likely to get carcinoma. Neoplasms are located on the periphery of the organ and are asymptomatic for a long time. But they have a rather difficult prognosis.
3. Non-small cell cancer is a rare disease that is a small tumor. It occurs in adults and older people and actively metastasizes because it is based on immature cancer cells.
4. The mixed form of lung cancer is a histological variant of the structure of the formation, in which there are several types of cells in one neoplasm.

Extremely rare variants of the disease are tumors of an organ from auxiliary elements of its structure: sarcoma, hemangiosarcoma, lymphoma. They all have fairly aggressive growth rates.

Tumors of any organ are divided by oncologists into several subtypes:

• Highly differentiated - the cells are close to mature in composition and have the most favorable prognosis.
• Moderately differentiated - the stage of development of elements is closer to intermediate.
• Poorly differentiated variants of lung cancer are the most dangerous, develop from immature cells and often metastasize.

The options listed above have their own development mechanisms and risk factors. Histology for lung cancer also determines methods of treating the disease.

Clinical forms of lung cancer

It is very important to determine the macroscopic location of lung cancer; classification involves dividing the disease into central and peripheral variants.

Central types of lung cancer are located deep in the organ, closer to the main bronchi. They are characterized by the following features:

• Accompanied by cough and shortness of breath.
• They are large in size.
• They are most often classified as squamous cell tumors.
• The clinical picture quickly appears.
• Easier to diagnose.
• They spread bronchogenically or through lymph flow.

Characteristics of peripheral neoplasms:

• Small size.
• They belong to adenocarcinomas.
• They have scant symptoms.
• Metastases spread mainly through blood.
• Detected in late stages.

The listed localization features influence not only the diagnostic process, but also the choice of treatment tactics. Sometimes surgery is not possible due to the location of the tumor.

TNM classification of lung cancer

In modern medicine, doctors are forced to classify diseases according to international standards. In oncology, the basis for tumor division is the TNM system.

The letter T stands for tumor size:

• 0 – the primary tumor cannot be found, so the size cannot be determined.
• is – cancer “in place”. This name means that the tumor is located on the surface of the bronchial mucosa. Well treated.
• 1 – the largest size of the formation does not exceed 30 mm, the main bronchus is not affected by the disease.
• 2 – the tumor can reach 70 mm, involves the main bronchus or invades the pleura. Such formation may be accompanied by pulmonary atelectasis or pneumonia.
• 3 – formation larger than 7 cm, extends to the pleura or diaphragm, less often involves the walls of the chest cavity.
• 4 – such a process already affects nearby organs, the mediastinum, large vessels or even the spine.

In the TNM system, the letter N stands for lymph node involvement:

• 0 – the lymphatic system is not involved.
• 1 – the tumor metastasizes to the first-order lymph nodes.
• 2 – the lymphatic system of the mediastinum is affected from the side of the primary tumor.
• 3 – distant lymph nodes are involved.

Finally, the letter M in the classification denotes distant metastases:

• 0 – no metastases.
• 1a – foci of screening in the opposite lung or pleura.
• 1b – metastases in distant organs.

As a result, the characteristics of the tumor may look like this: T2N1M0 - a tumor from 3 to 7 cm, with metastases to first-order lymph nodes without damage to distant organs.

Stages of lung cancer

Classification of lung cancer by stage is necessary to determine prognosis. It is domestic and widely used in our country. Its disadvantage is subjectivity and a separate division for each organ.

The following stages are distinguished:

• 0 – the tumor was accidentally discovered during diagnostic procedures. The size of the neoplasm is extremely small, there is no clinical picture. The organ lining and lymphatic system are not involved.
• 1 – size less than 30 mm. Corresponds to T1 form according to the international system. In this case, the lymph nodes are not affected. The prognosis is good with any type of treatment. It is not easy to detect such a formation.
• 2 – the size of the primary lesion can reach 5 cm. In the lymph nodes along the bronchi there are small foci of screening.
• 3A – the formation affects the layers of the pleura. The size of the tumor is not important in this case. Usually at this stage there are already metastases in the mediastinal lymph nodes.
• 3B – the disease involves the mediastinal organs. The tumor can invade blood vessels, the esophagus, myocardium, and vertebral bodies.
• 4 – there are metastases in distant organs.

In the third stage of the disease, a favorable outcome occurs only in a third of cases, and in the fourth stage the prognosis is unfavorable.

Each method of dividing a disease has its own purpose in clinical medicine.