Lung cancer develops when abnormal cells in the lungs grow uncontrollably and form tumours. These cancer cells can invade nearby tissues and spread to other parts of the body. Lung cancer remains a major public health challenge because of its high incidence and mortality and because it is often diagnosed at an advanced stage.[1]
There are two main types of lung cancer:
- Non-small cell lung cancer (NSCLC): The most common type, accounting for approximately 85% of lung cancers. Major subtypes include adenocarcinoma, squamous cell carcinoma and large cell carcinoma.[1]
- Small cell lung cancer (SCLC): A less common but more aggressive form of lung cancer that tends to grow and spread rapidly.[1]
Tobacco smoking is the major risk factor for lung cancer. Other important risk factors include exposure to second-hand tobacco smoke, outdoor and household air pollution, radon, and occupational carcinogens such as asbestos, silica and diesel exhaust.[1]
Global Impact
Lung cancer is the most commonly diagnosed cancer and the leading cause of cancer death worldwide. In 2024, approximately 2.6 million people were diagnosed with lung cancer, accounting for about 12.8% of all new cancer cases globally. Lung cancer was also responsible for approximately 1.9 million deaths, representing about 19.1% of all cancer deaths worldwide.[2]
The high burden of lung cancer is closely linked to preventable risk factors. Tobacco smoking remains the principal risk factor, while second-hand smoke, air pollution and occupational exposures also contribute to the disease burden. [1,2]
Impact in India
According to IARC GLOBOCAN 2022 estimates, approximately 81,748 new cases of lung cancer occurred in India, accounting for 5.8% of all new cancer cases in the country. Lung cancer was the fourth most commonly diagnosed cancer overall in India.[3]
The burden is particularly high among men. Approximately 58,970 new lung cancer cases occurred among Indian men, accounting for 8.5% of all cancers in males. Lung cancer was the second most commonly diagnosed cancer among Indian men, after lip and oral cavity cancer.[3] National Cancer Registry data also demonstrate considerable geographical variation in lung cancer incidence in India. The NCRP reported a significant increase in lung cancer incidence in 5 Population-Based Cancer Registries (PBCRs) among males and 11 PBCRs among females. Among women, Aizawl district recorded an age-adjusted incidence rate of 37.9 per 100,000, the highest reported among the Asian populations compared in the NCRP report.[4]
Signs and Symptoms
Lung cancer may not produce noticeable symptoms during its early stages. Common signs and symptoms include:[1]
- Persistent or worsening cough
- Coughing up blood
- Chest pain
- Shortness of breath
- Recurrent lung infections
- Loss of appetite
- Unexplained weight loss
- Persistent fatigue.[1]
Symptoms may become more extensive when lung cancer spreads to other parts of the body. Persistent or unexplained respiratory symptoms require appropriate medical evaluation.[1]
Treatment Modalities
Treatment of lung cancer depends on the type and stage of cancer, molecular characteristics of the tumour and the individual's overall health. Treatment may involve one or a combination of surgery, radiation therapy, chemotherapy, targeted therapy and immunotherapy.[1]
- Surgery: Surgery is primarily used for early-stage lung cancer when the tumour is localized and can be removed. Surgical procedures may involve removal of a small part of the lung, a lung segment or an entire lobe. Surgery is mainly used for NSCLC and has a more limited role in SCLC because SCLC tends to spread early [1]
- Radiation Therapy: Radiation therapy uses high-energy radiation to destroy cancer cells. It may be used when surgery is not possible, combined with other treatments for locally advanced disease, or used to relieve symptoms caused by advanced cancer.[1]
- Chemotherapy: Chemotherapy uses medicines to destroy or control cancer cells throughout the body. It may be used before or after surgery in NSCLC and is an important component of treatment for SCLC. It can also be combined with radiation therapy or immunotherapy.[1]
- Targeted Therapy: Some lung cancers have specific molecular or genetic alterations that can be targeted with particular medicines. Molecular or biomarker testing can help identify patients who may benefit from targeted treatment.[1]
- Immunotherapy: Immunotherapy helps the body's immune system recognize and attack cancer cells. It is used for selected patients with NSCLC and SCLC and may be administered alone or in combination with other treatments.[1]
Early Detection
Lung cancer is frequently diagnosed at an advanced stage, when treatment options are more limited. Screening of appropriately selected high-risk individuals, particularly current or former heavy smokers, can help detect lung cancer at an earlier stage and improve outcomes.[1]
References
1. World Health Organization. Lung cancer. Geneva: World Health Organization; 2026 Apr 16 [cited 2026 Sep 9]. Available from: https://www.who.int/news-room/fact-sheets/detail/lung-cancer
2. International Agency for Research on Cancer. Global cancer statistics 2024: GLOBOCAN estimates of incidence and mortality worldwide for 34 cancers in 186 countries. Lyon: International Agency for Research on Cancer; 2026 Jul 8 [cited 2026 Sep 9]. Available from: https://www.iarc.who.int/news-events/global-cancer-statistics-2024-globocan- estimates-of-incidence-and-mortality-worldwide-for-34-cancers-in-186-countries/
3. International Agency for Research on Cancer. Global Cancer Observatory: India fact sheet. GLOBOCAN 2022. Lyon: International Agency for Research on Cancer; 2024 [cited 2026 Sep 9]. Available from: https://gco.iarc.who.int/media/globocan/factsheets/populations/356-india-fact-sheet.pdf
4. Indian Council of Medical Research-National Centre for Disease Informatics and Research (ICMR-NCDIR). Report of National Cancer Registry Programme 2020. Bengaluru: ICMR-NCDIR; 2020. Available from: https://www.ncdirindia.org/All_Reports/Report_2020/resources/NCRP_2020_2012_16.pdf