Lung Cancer Overview

Lung Cancer

Lung cancer is the leading cause of cancer-related deaths worldwide. It is a highly invasive and rapidly metastasizing cancer, with approximately 224,210 new cases and 159,260 deaths predicted in the United States during 2014. Lung cancer is divided into two main histologic classes: small-cell lung carcinomas (SCLC) and non-small cell lung carcinomas (NSCLC).

Etiology

Lung cancer is predominantly caused by tobacco smoking, with approximately 90% of cases attributable to cigarette smoking and other forms of tobacco use. Other factors contributing to lung cancer include exposure to radon gas, asbestos, air pollution, and chronic infections.

Risk Factors

Major risk factors for lung cancer include:

• Tobacco smoking: The leading cause of lung cancer, with a higher risk for smokers compared to non-smokers.
• Exposure to radon gas: A radioactive gas found in soil, which can contaminate homes and buildings, increasing the risk of lung cancer.
• Exposure to asbestos: A naturally occurring mineral that can cause lung cancer when inhaled, often due to occupational exposure.
• Exposure to air pollution: High levels of air pollution, particularly in urban areas, can contribute to lung cancer.
• Chronic infections: Certain viruses and bacteria, such as HPV and Mycoplasma, can increase the risk of lung cancer.

Types

Lung cancer is classified into two main types:

• Small cell lung carcinomas (SCLC): Accounting for 10-15% of all lung cancer cases, SCLC is a highly aggressive cancer that often spreads quickly.
• Non-small cell lung carcinomas (NSCLC): The most common type of lung cancer, accounting for 80-85% of cases. NSCLC includes adenocarcinomas, squamous cell carcinomas, and large cell anaplastic carcinomas.

Treatment

Treatment options for lung cancer include surgery, radiation therapy, chemotherapy, and targeted therapy. The choice of treatment depends on several factors, including the type and stage of cancer.

• Surgery: For early-stage lung cancer, surgery is often the best treatment option.
• Radiation therapy: Used for advanced cancer and when surgery is not possible.
• Chemotherapy: Used to treat advanced cancer and to reduce symptoms.
• Targeted therapy: Targets specific genes or proteins involved in cancer growth and progression.
• Immunotherapy: Uses the immune system to fight cancer, particularly for advanced NSCLC.

Prognosis

Despite advancements in diagnosis and therapy, the prognosis for patients with lung cancer remains unsatisfactory. However, a better understanding of the biology of these malignancies may lead to the development of more efficacious and specific drugs.

Prevention

Preventive measures include:

• Smoking cessation: The single most effective way to prevent lung cancer.
• Avoiding exposure to asbestos and radon gas: Proper ventilation and safety measures can reduce exposure.
• Reducing air pollution: Improving air quality can help prevent lung cancer.
• Early detection: Regular screening for lung cancer, particularly for high-risk individuals, can lead to early detection and treatment.

Despite the challenges associated with lung cancer, ongoing research and advancements in treatment are providing hope for patients and their families.