Lung-damaging activities associated with cancer

Lung cancer is a disease in which abnormal cells in the lungs grow out of control, resulting in a tumor. The most common cancer in 2020 according to the WHO was lung cancer which claimed 2.21 million deaths after breast cancer which reported 2.26 million deaths.

The exact reason why lung cancer occurs can be classically defined as “multifactorial”. It can be environmental factors and also genetic factors. A slight increase in prevalence is noted recently in young women, and the cause remains a mystery. As an oncologist, we regularly treat cancer of lung, head and neck and even stomach, bladder, etc., mainly caused by excessive smoking (smokeless / smoked / hookah / second-hand smoke). In most cases, what starts out as a fad turns into an obsession leading to fatal illness before the victim realizes it. Smoking is the most critical risk factor for the development of lung cancer. Two-thirds of all lung cancers are associated with smoking. But lung cancer in non-smokers remains a single, distinct entity (less than 100 cigarettes in a lifetime). According to one data, 19% of all lung cancers in women in the United States were non-smokers.

Some other factors that lead to lung cancer include:

Radon, a radioactive gas found naturally in soil and rocks. Radon is a gaseous decay product of uranium-238 and radium-226 which damages the pulmonary epithelium by emitting alpha particles. Aizawl distt, Mizoram has the highest indoor radon / thoron concentration and also the highest incidence of lung cancer in India.

Occupational Exposure: Commonly associated toxins include asbestos, chromium and arsenic and occupational exposure to organic dust (mining industry).

Arsenic has been implicated as a cause of lung cancer where it contaminates drinking water. Whole-genome sequencing of lung cancer from a never-smoker patient exposed to arsenic revealed an unusual mutation in the tumor protein p53 (TP53).

Dietary Factors: Higher consumption of fruits and vegetables and low fat foods may protect against lung cancer (healthiest eating pattern).

Indoor air pollutants such as cooking oil vapors and smoke from burning coal have been linked to lung cancer in women, especially in Asia (India).

Outdoor air pollution is also associated with the risk of lung cancer. Using ambient fine particles (PM2.5) as a measure of air pollution, there was a 15-27% increase in lung cancer mortality among non-smokers.

Underlying lung disease and treatment – Idiopathic pulmonary fibrosis, previous exposure to radiation therapy or chemotherapy.

Cancer causing viruses (oncogenic viruses) such as human papillomavirus types 16 and 18. There is also an increased association with HIV infection.

Genetic factors: Lung cancer was significantly more common in people with a positive family history, especially early-onset lung cancer (

Estrogen – The role of estrogen and other female hormones in lung cancer risk in women is uncertain, regardless of smoking status. Studies show that the majority of NSCLC express the estrogen receptor beta. Relationship between incidence of lung cancer and early menopause, use of hormone therapy (such as tamoxifen or HRT), age at first birth and number of children. However, the results are not consistent.

Inflammation and other mild lung disease – The risk of lung cancer was high in patients with a history of emphysema, chronic bronchitis, pneumonia, and tuberculosis. The increased risk concerns all histological types of lung cancer (adenocarcinoma, squamous cell, small cells).

Genetic conditions such as alpha-1 antitrypsin deficiency

Body mass index – there is an inverse relationship between body mass index (BMI) and lung cancer (especially small cell lung cancer), but it can be co-morbidities or other factors associates.

Certain vitamin and beta-carotene supplements have given puzzling results.

Use of opium (illicit drug derived from the poppy plant associated with an increased and dose-dependent risk of developing lung cancer.

Screening is a method of detecting cancer when there are no symptoms in a high-risk case: low-dose helical CT scan is the only early detection technique proven to reduce mortality in high-risk people lung cancer. People at high risk who require lung CT screening are long-time smokers. Lung cancer screening by chest x-ray and sputum cytology has not been shown to reduce lung cancer death rates.

Remember that “cancer” is first and foremost a “lifestyle disease”. Cancer can be cured if it is diagnosed early enough. Even if it doesn’t, treatment should improve your quality of life and help you live longer. In addition, we, as an oncologist, want to teach each individual to make their lifestyle choices wisely. Everyone has the right to their own life and health, and the decision on this is up to them.

The article was written by Dr Niti Raizada, Director, Medical Oncology and Hematology-Oncology, Fortis La Femme Hospital, Richmond Road, Bangalore.