Lung Cancer Risk After Quitting Smoking: What an Oncologist Says

Quit Smoking: How Your Lung Cancer Risk Changes Over the Years

Quitting smoking is one of the most important steps a smoker can take to reduce the long-term health risks associated with tobacco. Although the effects of previous smoking may not disappear completely, the body begins to recover soon after the last cigarette, and the risk of lung cancer falls over time.

Dr Kumar Prabhash, Professor of Medical Oncology and Head of the Solid Tumour Unit at Tata Memorial Hospital and Director of Homi Bhabha Cancer Institute, Muzaffarpur, explained to HT Lifestyle how lung cancer risk changes after smoking cessation.

• Recovery starts soon after quitting
• The health benefits of stopping smoking begin much earlier than many people realise.

Dr Prabhash said carbon monoxide levels in the blood can return to normal within about 12 hours of quitting. During the following weeks and months, lung function may improve, while symptoms such as coughing and breathlessness can gradually reduce.

The decline in lung cancer risk takes longer and continues over the years.

“After 10 years of quitting, the risk of developing lung cancer is around 30–60% lower than in someone who continues to smoke,” Dr Prabhash said.

Smoking cessation can also reduce the risk of several other cancers. These include cancers of the liver, pancreas, bladder, kidney, stomach and colorectum, among others.

Former smokers still carry some additional risk

Quitting smoking significantly lowers the likelihood of developing lung cancer, but a former smoker’s risk does not necessarily become identical to that of someone who has never smoked. “Quitting significantly lowers lung cancer risk, but former smokers continue to have a higher risk than never-smokers,” Dr Prabhash said.

The level of remaining risk can vary depending on a person’s previous smoking history, including how much and for how long they smoked. “Quitting does not reset the clock, but it does stop further exposure and gives the body an opportunity to recover,” he added.

In other words, quitting cannot completely reverse every effect of past tobacco exposure, but it prevents additional exposure and allows the body to repair itself to the extent possible.

Screening can help detect problems earlier

For people with a substantial history of smoking, discussions with a doctor about lung health and whether screening is appropriate can be important.

Advances in screening and diagnostic techniques are helping doctors identify suspicious lung nodules earlier in eligible patients. At the same time, molecular testing and next-generation sequencing are providing additional information about the biology of individual tumours.

These developments have expanded the range of treatments available for lung cancer.

“Treatment now involves many options, such as surgery, radiotherapy, chemotherapy, targeted therapy or immunotherapy, used alone or in combination depending on the type and stage of the cancer,” Dr Prabhash said.

Access to treatment remains an issue

Early diagnosis and advances in treatment are only part of the challenge. Access to specialised cancer care can vary considerably across India.

Patients outside major urban centres may experience delays in diagnosis, specialist consultations, molecular testing or treatment. Dr Prabhash stressed the importance of improving healthcare pathways and collaborations so that comprehensive lung cancer services reach more patients.

He also pointed to initiatives aimed at improving access to precision diagnostics. Dr Prabhash said industry partnerships such as the LuNGS Alliance could help address gaps in molecular testing and support treatment decisions.

The Cancer Research and Statistics Foundation has also developed an industry consortium involving organisations from healthcare, pharmaceuticals and diagnostics, including AstraZeneca, Pfizer, Roche and 4baseCare, with the stated aim of expanding access to innovative lung cancer care.

Quitting still makes a difference

For smokers, the benefits of quitting begin well before the reduction in lung cancer risk becomes substantial. Carbon monoxide levels can fall within hours, respiratory health can improve over the following months, and the risk of lung cancer continues to decline over the longer term.

While quitting does not completely eliminate the risk associated with past smoking, stopping tobacco exposure remains an important step toward reducing future health risks. Former smokers with significant smoking histories should discuss their individual risk and possible screening needs with a healthcare professional.