Lung cancer

Lung cancer is a malignant neoplasm that develops from the epithelial tissue of the respiratory tract and alveoli. According to the WHO morphological classification, non-small cell lung cancer (squamous cell, adenocarcinoma, large cell) and small cell lung cancer are distinguished. The pathogenesis of the disease is characterized by invasive tumor growth with metastasis to regional lymph nodes and distant organs. The clinical picture in the early stages often remains asymptomatic, which significantly complicates timely diagnosis. The progression of the disease is accompanied by severe intoxication, respiratory failure and the development of paraneoplastic syndromes.

History of the disease and interesting historical facts

The first description of malignant neoplasms of the lungs dates back to 1761, when Giovanni Morgagni described autopsy cases in detail. Rudolf Virchow and Laennec made a significant contribution to the study of the disease, developing methods of differential diagnosis. It is interesting to note that until the beginning of the 20th century, the disease was considered rare - the first epidemiological studies in the 1920s showed a sharp increase in the incidence associated with the widespread use of smoking. "Between 1930 and 1950, there was a fivefold increase in the incidence of lung cancer, which coincided with the peak of smoking popularity," - notes a study in the Journal of Thoracic Oncology, 2018.

Epidemiology (statistics of disease occurrence)

According to the International Agency for Research on Cancer (IARC), about 2.2 million new cases of the disease are registered annually. The proportion of lung cancer in the structure of oncological morbidity is 11.4% among men and 8.4% among women. Mortality from the disease remains high - more than 1.8 million cases annually. The highest incidence rates are observed in developed countries:

• USA – 59 cases per 100,000 population
• European Union – 52 cases per 100,000
• Russia – 48 cases per 100,000

The median age at diagnosis is 65-70 years.

Genetic predisposition to the disease (involved genes and mutations)

Genetic predisposition plays a significant role in the development of the disease. The main mutations affect the following genes:

• EGFR (epidermal growth factor)
• KRAS (proto-oncogene)
• ALK (anaplastic lymphoma kinase)
• TP53 (tumor suppressor)
• BRAF (serine/threonine kinase)

Polymorphism of the CYP1A1 gene is associated with an increased risk of developing the disease in smoking patients. Studies show that EGFR mutation carriage occurs in 10-15% patients with non-small cell lung cancer.

Risk factors for the development of this disease

The main risk factors include:

• Tobacco smoking (responsible for 85-90% cases)
• Occupational hazards (asbestos, arsenic, chromium, nickel)
• Radiation exposure (radon)
• Air pollution
• Chronic inflammatory lung diseases

A combination of factors plays a special role: “The combination of smoking and occupational exposure to asbestos increases the risk of developing the disease by 50-100 times,” according to research from the US National Cancer Institute.

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Diagnosis of this disease

The clinical picture is characterized by the following manifestations:

• Unproductive cough
• Hemoptysis
• Chest pain
• Dyspnea
• Weight loss

Laboratory diagnostics include a complete blood count, biochemical markers (CEA, CYFRA 21-1). Radiological methods include CT, PET-CT and chest X-ray. Cytological examination of sputum and biopsy material are the basis for morphological verification of the diagnosis.

Treatment

Therapeutic tactics are determined by the stage of the disease and the morphological variant of the tumor. The main treatment areas include:

• Surgical intervention (lobectomy, pneumonectomy)
• Chemotherapy (platinum-containing drugs)
• Targeted therapy (EGFR, ALK inhibitors)
• Radiation therapy
• Immunotherapy (checkpoint inhibitors)

List of drugs used to treat this disease

Main groups of drugs:

• Cisplatin, Carboplatin
• Pemetrexed
• Gefitinib, Erlotinib
• Crizotinib, Alectinib
• Nivolumab, Pembrolizumab

Disease monitoring

Monitoring of treatment effectiveness includes regular CT scans every 3 months in the first year after completion of therapy. Main complications:

• Metastatic brain damage
• Pleural effusions
• Paraneoplastic syndromes

The five-year survival rate for locally advanced disease is 20-25%.

Age-related features of the disease

Patients over 70 years of age have a more aggressive course of the disease with rapid progression. At a young age, peripheral adenocarcinoma with EGFR mutations is more often diagnosed. “In patients under 40 years of age, the frequency of EGFR mutations reaches 30-35%” – data from the Lung Cancer study, 2020.

Questions and Answers

• How often should you get tested if you have risk factors? Annual CT screening is recommended for smokers over 55 years of age with a smoking history of more than 30 pack-years.
• Is a complete recovery possible? With early diagnosis and radical treatment, five-year survival reaches 60-70%.
• How does quitting smoking affect prognosis? Smoking cessation reduces the risk of relapse by 30-40%.

Advice from Dr. Oleg Korzhikov

Patients often ask about disease prevention. I recommend:

• Complete cessation of smoking and minimization of passive exposure to tobacco smoke
• Regular ventilation of premises to reduce radon concentrations
• Annual preventive examination in the presence of risk factors

In response to the question about early symptoms, I note: even a single case of hemoptysis requires immediate attention from a specialist.