Small cell lung cancer

Small cell lung cancer (SCLC) is a malignant neuroendocrine tumor characterized by the presence of cancerous cells in lung tissues.

This tumor originates from Kulchitsky (K) cells, a type of pulmonary neuroendocrine cell located in the respiratory tract epithelium. It typically begins in the bronchi.

SCLC is strongly associated with smoking, occurring primarily in smokers or former smokers. It is an aggressive, fast-growing cancer that spreads more quickly than other types of lung cancer, accounting for 10–15% of all lung cancer cases.

The symptoms of small cell lung cancer (SCLC) vary depending on whether the tumor is confined to the lung or has spread to other organs (metastasis).

Some of the initial signs include:

• Persistent chest pain.
• A chronic cough that differs from usual patterns, sometimes accompanied by blood (hemoptysis).
• Shortness of breath (dyspnea).
• Wheezing or whistling sounds during breathing.
• Fatigue or general weakness.
• Unexplained weight loss.
• Bone pain.
• Fever.
• Difficulty swallowing (dysphagia).

As the cancer progresses, symptoms depend on the affected organs and may include:

• Significant weight loss.
• Severe pain in bones and muscles.
• Neurological symptoms, such as headaches, fainting (syncope), seizures, weakness in the limbs, or changes in mental state.
• Hoarseness (dysphonia) or complete loss of voice (aphonia).
• Swelling of the face and neck.

In addition, during a physical examination a doctor may observe signs such as enlarged liver (hepatomegaly), swollen lymph nodes (greater than 1 cm) or masses detected in other parts of the body.

Lung cancer, including small cell lung cancer, is often diagnosed in advanced stages when metastases have already occurred. This delay is primarily due to the absence of noticeable symptoms in the early stages.

In some cases, early diagnosis can significantly improve life expectancy.

Ideally, cancer should be detected before symptoms appear, although this is challenging. To address this, early screening is recommended for individuals at high risk, such as long-term smokers.

Chest X-rays are not effective for early detection. However, low dose computed tomography without contrast has proven effective in individuals over 60 who have smoked more than 10 pack years.

In patients presenting symptoms, the diagnostic process typically includes imaging studies. Computed tomography and magnetic resonance imaging are used to identify the tumor's location and determine its spread.

The definitive diagnosis is confirmed by a biopsy. Tissue samples are analyzed under a microscope to identify cancerous cells.

Biopsy samples can be obtained through:

• Bronchoscopy, a procedure using a thin, flexible tube inserted through the airways to access the tumor.
• Ultrasound guided biopsy, performed through the skin to collect tissue from the lung or metastasis.

There are two main types of small cell lung cancer:

• Small cell lung carcinoma: The most common form.
• Combined small cell lung carcinoma: A less common variant that includes features of small cell carcinoma along with other types of lung cancer.

Staging is the process of determining the extent of cancer in the lung, nearby areas, and the rest of the body. This classification is essential for planning treatment and evaluating the prognosis.

Thus, we can discern the following stages depending on whether cancer cells are found in:

• Limited Stage: Cancer cells are confined to one lung and may involve nearby lymph nodes.
• Extensive Stage: Cancer has spread beyond the lung to other areas in the chest or distant parts of the body.
• Recurrent Stage: Cancer reappears after initial treatment, either in the same location or elsewhere in the body.

Treatment for small cell lung cancer (SCLC) varies based on the stage of the disease and individual patient factors. The main treatment options include:

• Surgery: Typically used in the limited stage if the tumor is small and confined.
• Radiotherapy: Applied to the main tumor, metastases, or as prophylactic cranial radiotherapy to prevent the spread to the brain.
• Chemotherapy: Used in extensive stage of SCLC to target cancer cells throughout the body.

The prognosis and choice of treatment depend on the stage of the cancer, tumor size, and specific characteristics of the disease.

LIMITED STAGE

1. Chemotherapy and chest radiotherapy, with or without prophylactic cranial radiotherapy.
2. Chemotherapy alone, with or without prophylactic cranial radiotherapy.
3. Surgery followed by chemotherapy, with or without prophylactic cranial radiotherapy.

EXTENSIVE STAGE

1. Chemotherapy and chest radiotherapy, with or without prophylactic cranial radiotherapy.
2. Chemotherapy alone, with or without prophylactic cranial radiotherapy.
3. Radiotherapy for metastases (e.g., brain, bones).

RECURRENT STAGE

1. Radiotherapy to relieve pain and manage symptoms.Immunotherapy to boost the body's immune response against cancer cells.

The prognosis for small cell lung cancer (SCLC) is generally less favorable than for other types of lung cancer due to its aggressive nature and rapid spread. Early diagnosis and treatment can improve outcomes, but survival rates remain lower compared to non-small cell lung cancer.

While small cell lung cancer cannot be completely prevented, certain risk factors can be avoided to reduce the likelihood of developing this disease.

• Smoking tobacco.
• Passive smoking (exposure to secondhand smoke).
• Exposure to radon.
• Exposure to asbestos.
• Contact with other carcinogenic substances, such as radioactive materials, arsenic, chromium, and carbon products.

In addition, it is recommended to follow a balanced diet and maintain a healthy weight, avoiding overweight and obesity.