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Lung cancer
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Lung cancer

Lung cancer is a disease where abnormal cells in the lungs grow uncontrollably, often linked to long-term tobacco smoking and specific genetic mutations.

Overview

Lung cancer occurs when cells in the lungs become abnormal and divide uncontrollably. It is generally divided into two main types based on cell size: small cell lung cancer (15% of cases) and non-small cell lung cancer (85% of cases). Lung cancer is the leading cause of cancer deaths in the United States.

Symptoms

Early stages may be asymptomatic. Common symptoms include:

  • Chest pain and frequent coughing
  • Blood in the mucus
  • Breathing problems, trouble swallowing, or speaking
  • Loss of appetite, weight loss, and fatigue
  • Swelling in the face or neck

Types of Lung Cancer

Small Cell Lung Cancer

This type grows quickly and often has spread (metastasized) by the time of diagnosis, commonly to the liver, brain, bones, and adrenal glands.

Non-Small Cell Lung Cancer

This type is divided into three main subtypes:

  • Adenocarcinoma: Arises from cells lining the small air sacs (alveoli).
  • Squamous cell carcinoma: Arises from squamous cells lining the passages leading to the lungs (bronchi).
  • Large cell carcinoma: Encompasses cancers that do not appear to be adenocarcinomas or squamous cell carcinomas.

Causes

Lung cancer is caused by the accumulation of genetic mutations in genes that control cell growth and division. In most cases, these are somatic mutations acquired during a person's lifetime, often due to exposure to carcinogens like tobacco smoke, radon, or air pollution. Common mutations occur in the TP53, EGFR, and KRAS genes. While rare, some individuals inherit germline mutations that increase their risk of developing the disease.

Inheritance

Most lung cancer cases are not inherited. When related to inherited genetic changes, the risk follows an autosomal dominant pattern. It is important to note that individuals inherit an increased risk of cancer, not the disease itself, and not everyone with these mutations will develop lung cancer.

Frequently Asked Questions

Common side effects include nausea, fatigue, hair loss, and decreased blood counts. Anti‑emetic medications, dose adjustments, growth‑factor support, and nutritional counseling can help. Patients should report new or worsening symptoms promptly, as early management can prevent complications and maintain treatment intensity.
family history can increase risk, especially if a first‑degree relative had lung cancer at a young age or had a smoking history. While routine genetic testing for lung cancer susceptibility genes (e.g., EGFR, KRAS, TP53) is not yet standard for all patients, individuals with strong family histories should discuss genetic counseling. Some centers offer multigene panels that include cancer‑predisposition genes, which can inform screening and prevention strategies.
Low‑dose computed tomography (LDCT) of the chest is the standard screening tool for adults aged 55–80 who have a 30‑pack‑year smoking history and currently smoke or quit within the past 15 years. LDCT can detect tumors as small as 4–5 mm, often before symptoms appear, allowing earlier intervention and improved survival.
Key measures include quitting smoking (if applicable), maintaining a healthy weight, engaging in regular aerobic exercise, limiting exposure to environmental pollutants, and following up with routine imaging as recommended by the treating oncologist. A balanced diet rich in fruits, vegetables, and omega‑3 fatty acids may also support overall health and immune function.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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