Overview
What Is Lung Cancer?
Lung cancer begins when abnormal cells in lung tissue grow uncontrollably and form a tumor. It can affect people who smoke, people who have never smoked, and people with different environmental or inherited risk factors. The lungs contain airways and air sacs that help the body take in oxygen, and cancer can begin in several types of cells there. The type and stage of lung cancer help guide treatment and provide information about how far the disease has spread.
MOST COMMON TYPE
Non-small cell lung cancer is the most common form and includes lung adenocarcinoma, squamous cell carcinoma, and less common subtypes. It is also called non small cell lung cancer or lung cancer NSCLC.
FAST-GROWING TYPE
Small cell lung cancer is less common and often grows and spreads more quickly than non-small cell disease. Its behavior and treatment approach differ from those used for NSCLC.
Symptoms
Lung Cancer Symptoms
- A persistent or worsening cough may be one of the early signs of lung cancer.
- Coughing up blood or rust-colored mucus should be medically assessed.
- Chest pain may worsen when breathing deeply or coughing.
- Shortness of breath or wheezing can occur with lung cancer or other lung conditions.
- Hoarseness may develop if a tumor affects structures near the voice box.
- Repeated bronchitis or pneumonia can occur when a tumor blocks an airway.
- Unexplained fatigue or weight loss may occur but can have many other causes.
More advanced disease may cause bone pain, headaches, weakness, jaundice, or swollen lymph nodes if cancer has spread or affects nearby structures. Not everyone with lung cancer develops these symptoms, and many can also result from other conditions.
Causes
What Causes Lung Cancer?
Lung cancer develops after DNA changes disrupt the normal controls that regulate lung-cell growth and repair. These changes can build up over time because of tobacco smoke, environmental or workplace exposures, aging, or chance. Risk factors can increase the likelihood of cancer, but no single factor explains every diagnosis and people should not be blamed for developing the disease.
- Tobacco smoking is the strongest preventable contributor to lung cancer.
- Secondhand smoke can increase risk even in people who have never smoked.
- Radon and certain workplace substances can damage lung tissue over time.
- Air pollution and other environmental exposures may contribute to risk.
- Previous radiation to the chest and some inherited changes can increase susceptibility.
Risk Factors
Lung Cancer Risk Factors
Modifiable and Potentially Reducible Risks
- Current or former cigarette, cigar, or pipe smoking increases risk.
- Long-term exposure to secondhand smoke can increase the likelihood of disease.
- Radon exposure in homes or workplaces can damage lung tissue.
- Workplace exposure to asbestos, arsenic, chromium, nickel, diesel exhaust, or silica can increase risk.
- Living in areas with substantial air pollution may contribute to risk.
Non-modifiable or Less Modifiable Risks
- Older age is associated with a higher likelihood of developing lung cancer.
- A personal or family history of lung cancer may increase risk.
- Previous radiation therapy to the chest can increase susceptibility.
- Certain chronic lung diseases or longstanding lung damage may contribute to risk.
- Inherited genetic susceptibility can make some people more vulnerable.
Side Effects & Complications
Complications and Treatment Side Effects
- A tumor can block an airway and cause infection or breathing problems.
- Fluid can build up around the lungs and make breathing difficult.
- Lung cancer can increase the risk of blood clots.
- Metastatic lung cancer may affect the brain, bones, liver, adrenal glands, or other organs.
- Advanced disease can cause pain, weakness, poor appetite, or significant weight loss.
Diagnosis & Staging
How Lung Cancer Is Diagnosed and Staged
- A clinician reviews symptoms, smoking history, exposures, and overall health.
- Chest X-ray or CT imaging may identify a suspicious lung nodule or mass.
- A biopsy removes cells or tissue for microscopic examination.
- Pathology determines whether the cancer is small cell or non-small cell and identifies its subtype.
- Molecular and biomarker tests may guide targeted therapy or immunotherapy choices.
How Staging Works
| Extent | What it generally means |
|---|---|
| Localized | The cancer is confined mainly to the lung or nearby structures. |
| Regional | The cancer involves nearby lymph nodes or tissues. |
| Distant or metastatic | The cancer has spread to distant organs or lymph nodes. |
Treatment Options
Lung Cancer Treatment Options
LOCAL TREATMENT
Surgery may remove a tumor or part of the lung and is usually considered for selected localized cancers.
LOCAL CONTROL
Radiation therapy uses focused radiation alone or with other treatments for local control or symptom relief.
SYSTEMIC MEDICINE
Chemotherapy uses medicines that travel through the body before or after surgery, with radiation, or for advanced disease.
BIOMARKER-BASED
Targeted therapy uses medicines selected for specific molecular changes found in the cancer.
IMMUNE-BASED
Immunotherapy helps the immune system recognize and attack cancer cells.
Lung cancer treatment may combine several modalities, depending on the cancer type, stage, biomarkers, symptoms, and overall health. Clinical trials may provide additional options, while symptom control, smoking cessation support, nutrition, rehabilitation, and palliative care can be included at any stage.
Prevention & Screening
Lung Cancer Prevention and Screening
- Do not smoke, and seek evidence-based help to quit if you smoke.
- Avoid secondhand smoke whenever possible.
- Test homes and workplaces for radon and correct elevated levels.
- Follow workplace safety measures around known carcinogens.
- Ask a clinician about reducing other personal risk factors.
SCREENING
Who may benefit from screening
Annual low-dose CT screening is generally intended for adults without symptoms who meet current high-risk criteria based on age and cumulative smoking history. It is not recommended for everyone; eligibility, benefits, risks, and when to stop should follow current national guidance and shared decision-making with a clinician.
Outlook and Prognosis
Lung Cancer Outlook and Prognosis
The outlook for lung cancer depends on the type and stage, biomarker results, overall health, response to treatment, and whether the disease is newly diagnosed or recurrent. A cancer specialist can interpret these factors together and explain what they may mean for an individual.
Type
Small cell and non-small cell cancers can behave differently.
Stage
The extent of spread is a major factor in outlook.
Biomarkers
Tumor biology may influence treatment choices and response.
Individual factors
Health, treatment response, and recurrence also matter.
Survivorship & Follow-up
Lung Cancer Survivorship and Follow-Up
- Attend follow-up visits and imaging at the schedule recommended by the cancer team.
- Report new or worsening symptoms rather than waiting for the next appointment.
- Ask about rehabilitation for breathing, strength, nutrition, pain, or fatigue.
- Review late and long-term treatment effects with the care team.
- Use emotional, social, financial, and palliative support services when needed.
Branches
3 topics
Lung Cancer
Medical Oncology
Lung Cancer
Pulmonology
Lung Cancer
Radiation Oncology
Symptoms
2 topics
Lung Cancer
Chest Pain
Lung Cancer
Cough
