Squamous cell lung carcinoma

Squamous cell lung carcinoma is a type of non-small cell lung cancer that originates from the squamous cells in the lining of the bronchi. It is the second most common subtype of lung cancer, accounting for approximately 30% of all cases.

Etiology

The primary risk factor for squamous cell lung carcinoma is smoking, with the majority of cases occurring in current or former smokers. Other risk factors include exposure to radon, asbestos, and certain other occupational carcinogens.

Pathogenesis

Squamous cell lung carcinoma typically arises in the central bronchi as a result of metaplastic and dysplastic changes in the bronchial epithelium. These changes are often associated with chronic irritation from smoking or other carcinogens. The tumor may then invade the bronchial wall, causing obstruction and leading to symptoms such as cough, hemoptysis, and recurrent pneumonia.

Diagnosis

The diagnosis of squamous cell lung carcinoma is typically made by bronchoscopy with biopsy. Histopathology reveals keratinizing squamous cells with intercellular bridges, which are characteristic of this type of cancer. Immunohistochemistry can also be used to confirm the diagnosis, with squamous cell carcinomas typically expressing p63 and cytokeratin 5/6.

Treatment

The treatment of squamous cell lung carcinoma depends on the stage of the disease at diagnosis. Early-stage tumors may be treated with surgery, while advanced cases may require chemotherapy, radiation therapy, or targeted therapies.

Prognosis

The prognosis of squamous cell lung carcinoma is generally poor, with a 5-year survival rate of less than 20%. Factors that influence prognosis include the stage of the disease at diagnosis, the patient's overall health, and the response to treatment.