Lung Cancer: Can Non-Smokers Get It Too? A Guide to Symptoms, Low-Dose CT Screening and Targeted Therapy

Lung cancer is the leading cause of cancer death in Hong Kong, claiming more lives each year than any other cancer. It is divided mainly into "non-small cell lung cancer" (about 85%, including adenocarcinoma and squamous cell carcinoma) and "small cell lung cancer" (which grows quickly and spreads early); the treatment strategies for the two are completely different.

It is worth noting that a significant proportion of lung cancer patients in Asia — especially women with adenocarcinoma — have never smoked. Whether you smoke or not, understanding the warning signs of lung cancer and screening methods is worthwhile for everyone.

Causes and Risk Factors

Smoking is the most important risk factor for lung cancer; the more you smoke and the longer you smoke, the higher the risk. Secondhand smoke is also harmful. After quitting, the risk falls year by year — it is never too late to quit.

Non-smoking-related risk factors include: radon (a naturally occurring radioactive gas that can be present in buildings), air pollution, long-term exposure to asbestos or certain industrial chemicals, a family history of lung cancer, and cooking fumes (some studies link this to lung cancer in Asian non-smoking women). Lung cancer in non-smokers is mostly adenocarcinoma and often carries gene mutations that can be treated with targeted therapy.

Common Symptoms and Warning Signs

Early lung cancer usually has no symptoms. Common warning signs include: a cough lasting more than three weeks, a change in the nature of a cough, coughing up blood or blood in the sputum, chest pain (worse with deep breathing or coughing), shortness of breath, hoarseness, repeated pneumonia or bronchitis, unexplained weight loss and fatigue.

These symptoms overlap with common respiratory conditions and are easily overlooked. If symptoms persist — especially in smokers or those with a family history — see a doctor promptly. A chest X-ray is the basic first step.

Diagnosis and Staging

Low-dose computed tomography (LDCT) is currently the most effective lung cancer screening tool; international studies confirm it can reduce lung cancer mortality in high-risk smokers. X-rays struggle to detect small early tumours. After a lung nodule is found, doctors decide on follow-up intervals based on its size and appearance, or confirm the diagnosis with bronchoscopy or needle biopsy.

After diagnosis, staging (stages I to IV) is completed with PET-CT, brain scans and other tests. For non-small cell lung cancer, genetic testing is a key step after diagnosis — mutations in EGFR, ALK, ROS1, KRAS, MET, RET and others all have corresponding targeted drugs, and the test results directly reshape the treatment plan.

Overview of Treatment Options

Early non-small cell lung cancer is treated mainly with surgical removal; those who cannot have surgery may receive stereotactic body radiotherapy (SBRT). After surgery, chemotherapy, targeted therapy or immunotherapy may be added depending on the stage to reduce the risk of recurrence. For locally advanced disease, concurrent chemoradiotherapy plus consolidation immunotherapy is the standard strategy.

Treatment for advanced disease has entered the era of precision medicine: patients with EGFR, ALK and other mutations take oral targeted drugs as first choice, with good efficacy and milder side effects than chemotherapy; those without driver mutations are treated mainly with immunotherapy (based on PD-L1 expression) plus chemotherapy. Small cell lung cancer is treated with chemotherapy plus immunotherapy as the foundation, together with radiotherapy. When resistance develops, newer-generation targeted drugs and ADC drugs offer further options.

Clinical Trials: One More Treatment Option

Lung cancer is the most active cancer type in global clinical trials: new-generation EGFR/ALK inhibitors, KRAS G12C targeted drugs, bispecific antibodies, ADC drugs and more are constantly emerging. After standard treatment fails, clinical trials are often the best way to access the newest drugs.

The CancerLink platform can match you to recruiting lung cancer clinical studies in Hong Kong by cancer type, stage and gene mutation; once successfully matched and enrolled, study-related treatment costs are fully covered. Patients are advised to keep a complete genetic testing report — this is the key to matching with a suitable trial.

Whether or not you smoke, a cough lasting more than three weeks is worth investigating. If you are unfortunately diagnosed with lung cancer, please have complete genetic testing first — it may directly find you an effective oral targeted drug. Lung cancer treatment has advanced more in the past decade than in the several decades before.