Lung Cancer

Definition and types of lung cancer

Lung cancer is a malignant tumor that develops from cells lining the bronchi or lung tissue. The tumor can infiltrate surrounding structures and metastasize to other organs, making the disease one of the main causes of cancer mortality.

Histological classification of lung cancer

Lung cancer is classified into two main types depending on its histological structure:

Non-small cell lung cancer (NSCLC) is the most common form, occurring in approximately 85% of cases. This group includes adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. NSCLC is characterized by relatively slow growth and a more favorable prognosis if detected early.

Small cell lung cancer (SCLC) is an aggressive type of tumor that quickly spreads throughout the body, metastasizing. It responds well to chemotherapy and radiation therapy, but in most cases it is detected at a late stage.

Oncopathology is also classified by location:

• Central - develops in large bronchi, manifested in the early stages by coughing, hemoptysis, and shortness of breath;
• Peripheral – develops in small bronchi and alveoli, and can proceed for a long time without any obvious symptoms.

Causes and risk factors

Lung cancer is caused by the influence of harmful environmental factors and hereditary predisposition. The main cause is long-term smoking - tobacco smoke contains a large number of carcinogens that provoke mutations in bronchial cells. The risk increases proportionally to the number of cigarettes smoked and the length of smoking.

Other risk factors include:

• Passive smoking - inhalation of tobacco smoke;
• Industrial hazards - contact with arsenic, chromium, asbestos, nickel, soot and other toxins;
• Air pollution - high concentration of fine particles and exhaust gases;
• Radiation exposure - increased radon levels in residential areas, consequences of radiation therapy;
• Chronic lung diseases - tuberculosis, chronic bronchitis and pneumosclerosis create favorable conditions for oncogenesis;
• Genetic predisposition – having relatives with oncopathologies increases the risk.

Risk factors often act in combination, accelerating the malignant transformation of cells.

Symptoms of Lung Cancer

The first signs of lung cancer

In the initial stages, the disease usually does not show obvious symptoms or imitates other pathologies. The first signs include persistent cough without obvious causes, periodic shortness of breath, rapid fatigue, loss of appetite and unexplained weight loss. Sometimes chest discomfort, subfebrile temperature and hoarseness appear.

Symptoms of lung cancer at different stages

At stages I–II, the symptoms are weakly expressed, coughing and periodic chest pain may occur. At stage III, the tumor causes increased coughing with sputum, hemoptysis, shortness of breath even at rest, pain in the chest and shoulder blade. Stage IV is characterized by severe weakness, anemia, severe intoxication, difficulty breathing and pain syndrome due to the spread of the process.

Symptoms of metastatic lung cancer

With metastasis, cancer can manifest itself with symptoms associated with damage to other organs. Liver metastases lead to jaundice and pain in the right side, in the bones - to intense pain and fractures, and in the brain - to headaches, impaired coordination, memory and speech impairment.

Symptoms of Pancoast tumor

A tumor located in the upper part of the lung causes intense pain in the shoulder and arm, as well as weakness in the muscles of the hand, numbness of the fingers, Horner's syndrome (ptosis, miosis, enophthalmos). These manifestations often lead to an erroneous diagnosis of a neurological or orthopedic disease.

Symptoms of peripheral and central lung cancer

Peripheral cancer remains asymptomatic for a long time and manifests itself only with a significant increase in the tumor - chest pain, pleurisy, hemoptysis. Central cancer located in large bronchi causes early persistent cough, bloody sputum, bronchial obstruction with dyspnea and pneumonia.

Features of the clinical picture in small cell lung cancer

Small cell lung cancer is characterized by an aggressive course and early metastases. Symptoms include severe weakness, severe dyspnea, severe exhaustion, intense chest pain, persistent cough with hemoptysis. Paraneoplastic syndromes are often noted: hyponatremia, neurological disorders, hormonal disorders.

Lung cancer stages: TNM classification

The TNM system is used to assess the extent of tumor spread:

• T (Tumor) – characteristics of the size and spread of the primary tumor;
• N (Nodes) – the degree of involvement of regional lymph nodes;
• M (Metastasis) – the presence of metastases in distant organs.

Depending on these indicators, four stages of the disease are distinguished:

Stage I – a small tumor (up to 3–4 cm), without involvement of lymph nodes and metastases. Symptoms are either absent or weak.

Stage II – the tumor increases in size, involvement of nearby lymph nodes is possible. Cough, shortness of breath and chest pain may be observed.

Stage III – the tumor spreads significantly, affecting the lymph nodes of the mediastinum, pleura and chest wall. Symptoms become pronounced: persistent cough, hemoptysis, shortness of breath, pain.

Stage IV – the tumor metastasizes to the liver, bones, and brain. The patient experiences severe weakness, anemia, severe intoxication, and pain.

Lung cancer diagnostics

Early diagnostics of lung cancer significantly increases the likelihood of successful treatment. The examination includes various clinical, instrumental and laboratory methods that help to identify the tumor, determine its type and stage.

Diagnostic methods

The main methods for detecting and assessing the spread of lung cancer:

• X-ray is a basic method that allows you to detect a tumor at a late stage;
• Computer tomography (CT) is a more accurate method that allows you to detect tumors at early stages of the disease;
• Positron emission tomography (PET-CT) is used to assess the spread of cancer and search for metastases;
• Bronchoscopy is an endoscopic examination of the bronchi with the possibility of biopsy;
• MRI is used to assess the involvement of soft tissues and search for metastases in the brain;

Thoracoscopy and biopsy are invasive methods for taking tissue samples and accurately determining the nature of the tumor.

Laboratory tests and molecular analysis of the tumor

Laboratory tests help to clarify the diagnosis and select personalized treatment:

• Cytological examination of sputum - allows to identify tumor cells in central cancer;
• Blood test for tumor markers - used as an additional diagnostic method;
• Histological and immunohistochemical examination - performed after a biopsy to determine the type of cancer;

Molecular genetic analysis - identifies mutations (EGFR, ALK, ROS1, etc.), which is important for the appointment of targeted therapy.

Lung cancer treatment

The treatment process is determined by the stage of the disease, the nature of the tumor and the patient's health. Each case requires a personalized approach, taking into account all the specific features of the disease.

Surgical treatment

Surgery is the main method of therapy for early stages of lung cancer. Depending on the location and spread of the tumor, the following types of surgical interventions are performed:

• Lobectomy – removal of the lobe of the lung affected by the tumor;
• Pneumonectomy – complete removal of the lung affected by the malignant process;
• Segmentectomy – excision of a certain segment of the lung with a tumor, while the remaining part of the organ retains its function;
• Lymphadenectomy – removal of nearby lymph nodes if metastases are found in them.

Chemotherapy and Targeted Therapy

Chemotherapy is used in later stages of lung cancer, as well as after surgery to reduce the risk of recurrence. The main drugs are platinum compounds and topoisomerase, which block the growth and division of tumor cells.

Targeted therapy is aimed at specific molecules that contribute to the development of the malignant process. It is prescribed to patients with certain genetic mutations (for example, in the EGFR, ALK, ROS1 genes). Such drugs affect the mechanisms that support tumor growth, which can significantly increase the effectiveness of treatment.

Radiation therapy

Radiation therapy is used as an independent method or in combination with surgery and chemotherapy. It is indicated in the following cases:

• for localized tumors, if surgical intervention is impossible;
• for palliative purposes - to reduce the size of the tumor and relieve symptoms in advanced cancer;
• as an adjuvant therapy - to destroy residual malignant cells after surgery.

Modern techniques, such as stereotactic radiotherapy, allow high doses of radiation to be directed directly to the tumor, minimizing damage to healthy tissue.

Treatment of lung cancer at different stages

The choice of treatment tactics depends on the stage of the oncological process:

Stages 1-2 – surgery followed by chemotherapy or targeted therapy;

Stage 3 – complex treatment, including surgery (if possible), chemotherapy and radiation therapy;

Stage 4 – mainly palliative therapy aimed at relieving symptoms and prolonging life. At this stage, chemotherapy, immunotherapy, targeted drugs and radiation are used.

Treatment methods can be combined with each other depending on the patient's condition and the characteristics of the tumor. If you are considering lung cancer treatment in Russia, the medical tourism platform MARUS will help you choose the right clinic and qualified specialists.

Prognosis and risk of relapse

The outcome of the disease depends on various factors, including the stage at the time of detection, the biological characteristics of the tumor, the effectiveness of therapy and the general health of the patient. In the early stages, when the malignant process is localized and has not metastasized, the prognosis is much more favorable, and the likelihood of long-term remission is higher. However, even with successful treatment, recovery of the body and compliance with medical recommendations play an important role.

The risk of relapse is especially high in the later stages, when the tumor has spread throughout the body or therapy has not completely eliminated cancer cells. In such cases, it is necessary to undergo regular follow-up examinations in order to detect a possible return of the disease in time. Modern treatment methods, including immunotherapy, targeted drugs and chemotherapy, can significantly reduce the likelihood of relapse, especially if tumor cells have certain genetic mutations.

Lung cancer prevention

Prevention includes measures aimed at reducing the risk of developing cancer. The main factor in preventing the disease is to quit smoking, as well as limiting contact with harmful chemicals. To maintain lung health, it is recommended to:

• a balanced diet rich in antioxidants and vitamins;
• regular exercise;
• enough time spent in the fresh air.

It is also important to treat chronic respiratory diseases in a timely manner and undergo preventive examinations to detect pathology at early stages and prevent its progression.