Overview
Lung cancer is the leading cause of cancer death in the UK and worldwide. There are two main types: non-small cell lung cancer (NSCLC, ~85% of cases) including adenocarcinoma and squamous cell carcinoma, and small cell lung cancer (SCLC, ~15%). SCLC grows and spreads more quickly. Smoking is the dominant cause but never-smokers are increasingly affected.
How common is it?
Lung cancer is common and causes more cancer deaths than any other cancer in the UK. It may cause few symptoms early on, which is why persistent changes and suitable screening matter.
Causes and risk factors
Tobacco smoke is the main cause of lung cancer. Carcinogens damage DNA in lung cells. Lung cancer can also develop in people who have never smoked, through a combination of genetic and environmental factors.
Common risk factors
- Cigarette, cigar, or pipe smoking (dose and duration-dependent)
- Passive smoking
- Radon gas (second most common cause after smoking, especially in granite geology areas)
- Occupational exposure: asbestos, arsenic, chromium, nickel, silica, diesel exhaust
- Air pollution (WHO Group 1 carcinogen)
- Family history and genetic factors
- Previous lung disease (COPD, pulmonary fibrosis)
- Lung cancer also occurs in people who have never smoked; genetic changes in the tumour can guide treatment.
Symptoms
- Persistent new cough or change in existing cough
- Haemoptysis (coughing up blood)
- Persistent breathlessness
- Chest pain or shoulder pain
- Unexplained weight loss and fatigue
- Recurrent chest infections
- Hoarseness (recurrent laryngeal nerve involvement)
- Superior vena cava obstruction: facial swelling, arm swelling, headache
- Finger clubbing
When to see a doctor
Seek urgent medical advice if you cough up blood. Call emergency services for severe breathing difficulty, chest or upper-back pain, or collapse. Contact a GP for a cough lasting more than three weeks or other persistent unexplained symptoms, including breathlessness or weight loss. Do not dismiss symptoms because you are younger or do not smoke. The clinician will decide which tests and referral are needed.
Diagnosis
Chest X-ray and CT thorax, abdomen, and pelvis. PET-CT for staging. Histological diagnosis by bronchoscopy, CT-guided biopsy, or EBUS (endobronchial ultrasound for mediastinal nodes). Molecular testing (EGFR, ALK, ROS1, PD-L1) for all advanced NSCLC to guide targeted therapy.
Treatments
Surgery (curative intent)
Surgery aims to cure selected early-stage non-small-cell lung cancers. The operation and whether a keyhole approach is suitable depend on tumour location, stage and fitness. Further treatment may be recommended.
Targeted therapy
Oral EGFR inhibitors (osimertinib) and ALK inhibitors (alectinib, crizotinib) produce dramatic responses in molecularly selected patients. First-line for EGFR-mutant and ALK-positive advanced NSCLC.
Immunotherapy
Anti-PD-1 and anti-PD-L1 checkpoint inhibitors (pembrolizumab, nivolumab, atezolizumab) produce durable responses in a subset of patients and have transformed advanced NSCLC management.
Chemotherapy
Chemotherapy may be used alone or with immunotherapy, depending on cancer type, stage, biomarkers and health. Platinum-based combinations are common; selected extensive-stage small cell cancers receive chemotherapy with immunotherapy.
Radiotherapy
Stereotactic ablative radiotherapy can be offered with curative intent for selected early NSCLC when surgery is unsuitable. Other radiotherapy regimens may be combined with systemic treatment or used to relieve symptoms.
Self-care and lifestyle
- Stop smoking immediately — even after a lung cancer diagnosis, stopping improves treatment outcomes and survival
- Maintain physical activity and nutrition to tolerate treatment
- Ask about testing your home for radon if you live in a higher-risk area; in the UK, use UKHSA's UKradon information.
- In England, people aged 55 to 74 who have ever smoked may be invited for a lung health check where screening is available; assessment determines whether low-dose CT is offered. Eligibility differs elsewhere. Do not wait for screening if you have symptoms.
Prevention
Not smoking is the most powerful preventive action. Radon reduction measures in high-risk homes, occupational exposure controls, and air pollution reduction are additional measures.
Sources for targeted updates
Updated: 24 October 2026. Targeted corrections to self-care, treatment, key facts, frequency, risk factors, causes. This update covers the named sections; a full review of the remaining guide is pending.