Small cell carcinoma

Small cell carcinoma is a type of cancer that commonly arises within the lung, but can occasionally occur in other body sites, such as the cervix, prostate, and gastrointestinal tract. It is characterized by small cells that are round, oval, or spindle-shaped. This type of cancer is also known as oat cell cancer due to the shape of the cells under a microscope.

Epidemiology

Small cell carcinoma accounts for approximately 15-20% of all lung cancer cases. It is strongly associated with cigarette smoking, with about 95% of cases occurring in current or former smokers. The incidence of small cell carcinoma has been decreasing over the past few decades, likely due to reductions in smoking rates.

Pathogenesis

The exact cause of small cell carcinoma is not known, but it is thought to begin when healthy cells in the lung make mistakes while copying their DNA during cell division. These mistakes, or mutations, can cause the cell to grow and divide uncontrollably, leading to the formation of a tumor. Small cell carcinoma is known to grow and spread more quickly than non-small cell lung cancer.

Clinical Features

Symptoms of small cell carcinoma can include cough, chest pain, shortness of breath, and unexplained weight loss. In some cases, the cancer can cause paraneoplastic syndromes, which are rare disorders triggered by the body's immune response to the cancer.

Diagnosis

Diagnosis of small cell carcinoma typically involves imaging tests, such as a chest X-ray or CT scan, and a biopsy to examine the cells under a microscope. The cancer is often staged as either limited (confined to one side of the chest) or extensive (spread beyond one side of the chest).

Treatment

Treatment for small cell carcinoma usually involves a combination of chemotherapy and radiation therapy. Surgery is rarely used due to the typically advanced stage of the disease at diagnosis.

Prognosis

The prognosis for small cell carcinoma is generally poor, with a five-year survival rate of less than 10%. However, survival rates can vary widely depending on the stage of the cancer at diagnosis and the patient's overall health.