Lung cancer is a cancer that begins in the tissues of one or both lungs. The two major types are non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC).
Lung cancer develops when abnormal cells in lung tissue grow without normal control and may invade nearby tissues or spread to other parts of the body. Smoking is the major risk factor, but people who have never smoked can also develop lung cancer.
The lungs exchange oxygen and carbon dioxide. Air passes through the trachea and bronchi into smaller airways ending in alveoli, where gas exchange occurs.
Lung cancer begins when cells in the lung acquire changes that allow uncontrolled growth and survival. Different lung cell types can produce different cancer types.
Genetic and cellular changes can cause lung cells to multiply abnormally. A tumor may grow within the lung, obstruct an airway, invade nearby structures, or spread through lymphatic or blood vessels.
Classification depends on microscopic appearance, tumor biology and molecular characteristics. For some NSCLC tumors, molecular testing and biomarker testing can influence targeted therapy or immunotherapy decisions.
The two main categories are non-small cell lung cancer and small cell lung cancer. NSCLC includes major subtypes such as adenocarcinoma, squamous cell carcinoma and large cell carcinoma. These categories differ in biology and treatment.
Persistent or worsening cough
Coughing up blood
Shortness of breath
Chest pain
Hoarseness
Repeated respiratory infections
Unexplained weight loss
Fatigue
Reduced appetite
Smoking causes most lung cancers, although lung cancer can also occur in people who never smoke. Other contributors include exposure to secondhand smoke, radon, certain workplace carcinogens and some forms of air pollution.
Current or previous tobacco smoking
Secondhand smoke
Increasing age
Radon exposure
Occupational exposure to certain carcinogens
Personal or family history in some situations
Evaluation may include medical history, physical examination, chest imaging and additional tests. A biopsy is generally needed to confirm that abnormal tissue is cancer and to determine its type. Additional molecular or biomarker testing may be used when relevant.
Persistent cough
Unexplained coughing of blood
New or worsening breathlessness
Persistent chest pain
Unexplained weight loss
Complete blood count when clinically indicated
Blood chemistry testing
Molecular or biomarker testing when appropriate
Chest X-ray
Chest CT
PET-CT when indicated
Brain MRI or other imaging when clinically indicated
Bronchoscopy
Image-guided biopsy
Pathology examination
Molecular biomarker testing
Pneumonia
Tuberculosis
Chronic obstructive pulmonary disease
Benign lung nodules
Other inflammatory lung diseases
For non-small cell lung cancer, staging commonly uses the TNM system and groups disease into stages 0 through IV. Small cell lung cancer is also commonly described as limited-stage or extensive-stage disease. Stage reflects tumor extent and spread and helps guide treatment.
Staging or grading systems differ between diseases. The information here is educational and should be interpreted by a qualified healthcare professional in the context of the individual case.
Treatment depends on cancer type, stage, molecular findings, overall health and treatment goals. Options may include surgery, radiation therapy, chemotherapy, targeted therapy and immunotherapy. Some patients receive combinations of these approaches.
Cancer medicines are selected according to cancer type, stage, biomarkers and treatment plan.
Examples of treatment categories include chemotherapy, targeted therapy and immunotherapy.
Supportive medicines may be used for symptoms or treatment side effects.
Medicines listed here are for educational information only. Do not start, stop, or change a medicine without professional medical advice.
Possible complications include airway obstruction, recurrent infections, bleeding, fluid around the lung, breathing difficulty, cancer-related pain and spread to distant organs. Treatment can also cause complications or side effects.
Severe difficulty breathing
Large-volume or rapidly worsening coughing of blood
Severe chest pain
Sudden confusion or weakness
Collapse or loss of consciousness
If symptoms are severe, rapidly worsening, or life-threatening, seek emergency medical care immediately.
Outlook varies substantially according to cancer type, stage, molecular characteristics, response to treatment and overall health. Population survival statistics describe groups and cannot predict exactly what will happen to an individual.
Survival statistics describe outcomes in groups of people and cannot predict exactly what will happen to one individual. Prognosis depends on factors such as cancer stage, tumor biology, treatment response, overall health, and follow-up.
Lung cancer is a major cancer worldwide. In India, GLOBOCAN 2022 estimated 81,748 new lung cancer cases across both sexes.
Risk reduction focuses strongly on tobacco avoidance and cessation, reducing secondhand smoke exposure and minimizing avoidable occupational or environmental carcinogen exposure.
What type of lung cancer is present?
What is the stage?
Is biomarker testing appropriate?
What treatment options are available?
What side effects should be reported urgently?
BimariDur provides educational health information to help people understand diseases, symptoms, tests, and treatment concepts. It does not replace examination, diagnosis, or treatment by a qualified healthcare professional.
Do not delay professional medical care because of information read on BimariDur.