At 34, Priya (name changed), an IT professional and marathon enthusiast, had little reason to worry. A non-smoker who kept to a strict fitness routine, she dismissed her ongoing cough and tiredness as effects of work pressure and seasonal changes. But as her breathlessness steadily increased over six weeks, she finally decided to get it checked. A chest X-ray revealed a mass in her right lung—and a further CT scan confirmed stage III non-small cell lung cancer.For Priya, the diagnosis was a double shock: first, that lung cancer could strike someone like her, and second, that it could advance so quickly under the radar. Up north in Haryana’s Panipat, 43-year-old Poonam Sharma, a school teacher, was troubled by a similar diagnosis that not only shocked her family but also shattered the common myth that lung cancer is only a smoker’s disease. “I had never smoked a single cigarette in my life. I led a healthy lifestyle, ate home-cooked food and did yoga. I never thought I could get lung cancer,” she told her doctor.Poonam initially experienced persistent fatigue, mild breathlessness and an occasional dry cough. There was no weight loss or coughing up blood — signs often associated with lung cancer. Her symptoms were subtle. When the breathlessness worsened, she visited a local physician. A chest X-ray showed a shadow in her right lung. A subsequent CT scan confirmed a suspicious lesion. A biopsy and PET-CT scan revealed that she had Stage II non-small cell lung cancer.Cases like Priya’s and Poonam’s are becoming increasingly common. Studies suggest that 15-20 per cent of lung cancer cases occur in people who have never smoked, mostly women. A study by the All-India Institute of Medical Sciences (AIIMS), Delhi, analysed the spectrum of lung cancer from several hospitals, using data from the National Cancer Registry Programme.WHAT NUMBERS TELL USA total of 45,228 patients – 34,395 men and 10,833 women – with lung cancer were included in this study. Nearly three-fourths of the lung cancer cases among men were diagnosed between 50 and 74 years of age, with incidence peaks between 60 and 64 years. Most cases in women showed up five years earlier than in men, with the majority (69.4 per cent) occurring between 45 and 69 years. “What’s more important is that most of these women are actually non-smokers,” says Dr Sunil Kumar, professor and head, surgical oncology, AIIMS.WHAT ARE TRIGGERS?Urban air pollution — fine particulate matter from vehicles and industry — carries carcinogens deep into the smallest airways. “Indoor pollutants such as biomass-fuel smoke, household chemicals, radon or second-hand tobacco add to the burden,” says Dr Rajeev Vijayakumar, medical oncologist, haemato-oncologist and BMT physician, Gleneagles BGS Hospital, Bengaluru. However, the kind of fuel, which has been traditionally used in kitchens, has remarkably changed but obviously it takes more than a decade to develop cancer. “What we are seeing is the long-term effect of environmental pollution,” says Dr Kumar.Also read | Why does lung cancer recur? It’s all in the genes, finds new studyHowever, both Poonam and Priya had a different reason. “Poonam had no history of smoking, exposure to industrial pollutants or family history of cancer,” explains Dr Raman Narang, haematologist and medical oncologist at Andromeda Cancer Hospital, Sonipat. “However, her biopsy revealed a genetic mutation in EGFR (Epidermal Growth Factor Receptor) that leads to uncontrolled cell growth. This mutation is more commonly found in non-smoking women of Asian descent, suggesting an ethnic predisposition,” he says. Studies show that EGFR mutations are found in a higher percentage of non-smokers (45.5 per cent) compared to smokers (15.1 per cent) in some studies.Story continues below this adWHY DO EGFR MUTATIONS TAKE PLACE IN NON-SMOKERS?EGFR mutations are not typically inherited but occur randomly in cells during a person’s life.They can predispose individuals to lung cancer, even if they have never smoked.WHAT ABOUT THERAPY?This form of lung cancer behaves differently and responds well to targetted therapy — oral medication that blocks the effect of the mutated EGFR protein responsible for the cancer’s growth.Poonam was started on EGFR-targeted oral therapy, a pill taken once daily. “Unlike traditional chemotherapy, this targeted treatment is less toxic and doesn’t lead to hair loss, nausea, or extreme fatigue,” says Dr Narang. Within a few months, her tumour had significantly reduced in size. She is now in her 18th month of treatment and doing well, with regular follow-ups and scans to monitor progress.Priya began with a tyrosine-kinase inhibitor and saw her tumour shrink by 60 per cent within three months, regaining strength and daily energy, according to Dr Vijayakumar.Story continues below this adCheck out | Fighting cancer: ICMR study reveals big gap in radiotherapy accessDO NOT DELAY DIAGNOSIS“Lung cancer should not be stereotyped as a smoker’s disease. Delayed diagnosis in non-smokers often happens because it’s not even considered a possibility,” warns Dr Narang. “When a cough doesn’t resolve, breathing becomes laboured, or weight drops without reason, it’s best not to delay a check-up. Acting early — even when cancer seems unlikely — can be life-saving,” says Dr Vijayakumar.The AIIMS study shows that a majority of lung cancer patients go to hospital in a very advanced stage. “For early-stage non-small cell lung cancer, surgery is often the best first option to remove the cancer and potentially cure the patient. But this cannot be done if patients report their condition at an advanced stage,” says Dr Kumar.WHEN SHOULD YOU CONSULT A DOCTORIn younger patients, early signs are easy to miss. Dr Vijayakumar flags symptoms like a mild cough, occasional chest tightness, or a twinge of back pain. “These rarely raise alarm bells until weight loss, haemoptysis (blood in sputum), or severe breathlessness occur. By then imaging often shows lymph node involvement or distant spread,” he says.He also calls for public education campaigns that explain how lung cancer can affect anyone, regardless of age or smoking history. “At the macro level, we must urge frontline physicians to explore early imaging when respiratory symptoms don’t resolve on their own. There should be stricter pollution controls and promotion of cleaner cooking fuels in homes,” adds Dr Vijayakumara.