Lung cancer- understanding lung cancer: causes, symptoms, and early detection

Lung cancer ranks among the most widespread cancers globally, impacting millions of individuals, including a significant number in India. Understanding how and why it develops-and recognising early warning signs-can make a meaningful difference to outcomes. Here, we cover the essentials: what lung cancer is, the leading causes and lung cancer symptoms, how early detection works, and how a coordinated clinical pathway supports timely, effective care.

What is lung cancer?

Lung cancer starts when abnormal cells in the lungs grow uncontrollably, forming a tumour. These cells may invade nearby tissues and eventually spread to distant areas of the body through metastasis.

Causes and risk factors

Lung cancer arises from a combination of environmental exposures and individual susceptibility. Some risk factors are modifiable; others are not.

• Smoking and second-hand smoke: Tobacco exposure remains the single largest risk factor. Long-term smokers and people regularly exposed to second-hand smoke are at significantly higher risk.
• Air pollution: In densely populated and industrialised areas-such as large metro cities-exposure to fine particulate matter, diesel exhaust, and industrial pollutants contributes to increased risk.
• Occupational hazards: Long-term exposure to substances such as asbestos, radon, and specific industrial chemicals-common in construction, mining, and some manufacturing settings-elevates risk.
• Pre-existing lung disease: Conditions that damage or weaken the lungs, such as chronic obstructive pulmonary disease (COPD) or a history of pulmonary infections like tuberculosis, can increase susceptibility. Reducing avoidable exposures-quitting smoking, improving indoor air quality, and using appropriate protective equipment at work-can help lower risk.

Symptoms to take seriously - early signs of lung cancer

Early lung cancer may cause few or subtle symptoms, which is why vigilance is key. Consult a doctor promptly if you notice any of the following-especially if they persist beyond two weeks:

• Persistent or changing cough: A cough that would not settle, or a new cough that steadily worsens.
• Sudden onset breathlessness: Shortness of breath during everyday activities such as walking or climbing stairs.
• Chest pain: Discomfort that may be felt when breathing deeply or coughing.
• Blood in sputum: Coughing up blood or blood-streaked mucus requires urgent medical attention.
• Fatigue: Ongoing, unexplained tiredness or weakness.
• Unintentional weight loss or reduced appetite: Particularly concerning when combined with other symptoms.
• Recurrent chest infections: Frequent or lingering bouts of bronchitis or pneumonia that do not respond as expected to standard treatment.

These symptoms do not always mean cancer, but timely assessment is essential to rule out serious conditions and begin appropriate care.

Early detection and screening

Finding lung cancer early improves the chances of successful treatment. Screening does not diagnose cancer on its own, but it helps identify abnormalities sooner-often before symptoms become obvious.

Key screening and evaluation methods include:

• Low-dose CT (LDCT) scans: Currently the most effective modality for lung cancer screening in high-risk individuals. LDCT can detect small nodules that may not be visible on a chest X-ray.
• Sputum cytology: Examines coughed-up mucus for abnormal cells. While less sensitive than LDCT, it can provide complementary information in certain cases.
• Chest X-ray: Useful for initial assessment, particularly when disease is advanced or for evaluating other chest conditions, but less sensitive than LDCT for early cancers.

Who should consider screening?

Individuals at high risk for lung cancer include those with more than 15 pack years of smoking history, even if they are currently non-smokers, as well as those with a family history of lung cancer in first-degree relatives. Additional risk factors include long-term smoking, substantial exposure to second-hand smoke, living in highly polluted areas. People in these categories should consult their doctor about screening options. A personalized risk assessment can help determine whether Low-Dose Computed Tomography (LDCT) or other tests are appropriate and when they should be done.

The importance of regular follow-up

Early detection is not a one-off event. For those at heightened risk, regular check-ups and periodic imaging can identify changes over time. For people previously treated for lung cancer, structured follow-up with imaging helps detect any recurrence early and guides swift intervention.

Paying attention to early signs

Common respiratory complaints can be easy to dismiss, but the pattern and persistence matter. A cough that lingers, unexplained weight loss, or repeated chest infections deserve proactive evaluation. If you are high-risk-because of smoking, occupational exposure, or family history-make a plan with your clinician for what symptoms should trigger a check and how frequently you should be screened.

Our clinical approach: comprehensive assessment and coordinated care

Our oncology department provides care aligned with international standards, bringing together advanced diagnostics and a multidisciplinary team to support you at every step-from evaluation through to treatment and recovery.

Advanced diagnostics for accurate assessment

• High-Resolution CT (HRCT): Offers detailed imaging of lung structures, helping to characterise nodules, map airway involvement, and guide subsequent decisions.
• Oncopathology services: Including Fine Needle Aspiration Cytology (FNAC) and core biopsies, supported by immunohistochemistry to confirm tumour type and inform targeted treatment planning.
• Bronchoscopic and thoracoscopic interventions.

Multidisciplinary, personalised treatment planning

We combine the expertise of medical oncologists, surgical oncologists, and radiation oncologists to create an individualised treatment plan. This integrated model ensures that each patient receives the most appropriate therapies, sequenced in the right order and timed to maximise benefit. Treatment options can include surgery (VATS/OPEN), radiotherapy, systemic therapies (such as chemotherapy, targeted therapies, or immunotherapy), or combinations tailored to tumour type and stage.

Support for whole-person wellbeing

Cancer care is about more than tumour control. We provide nutrition and lifestyle counselling to help patients maintain strength, manage side effects, and preserve quality of life throughout treatment. Practical guidance on activity, sleep, and symptom management complements medical care and can improve day-to-day comfort and resilience.