Smoking and cancer trials: A group of international cancer experts has called for mandatory recording of smoking status in cancer clinical trials, warning that continued tobacco use can reduce treatment efficacy and survival rates.
In a commentary published in The Lancet Oncology, researchers from AIIMS Delhi, McMaster University (Canada) and the International Agency for Research on Cancer (France) stressed that capturing smoking data is vital for improving therapeutic outcomes and guiding clinical decisions. The authors include Dr Abhishek Shankar of AIIMS Delhi.
They noted that, despite the evidence, oncology research frequently overlooks smoking status. “Knowledge of smoking status during cancer therapy could potentially influence clinical decisions,” the authors wrote, citing how smokers prescribed erlotinib, a lung cancer drug, require double the standard dose to achieve therapeutic levels.
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The experts noted that tobacco smoke can worsen cancer outcomes by reducing oxygen in tumours, altering drug metabolism, and weakening the immune system. Evidence from multiple studies shows patients who quit smoking after a cancer diagnosis live longer, with early cessation offering the greatest survival benefits, in some cases even outweighing the benefits of the therapy under trial.
The commentary highlighted barriers such as lack of standardised tools, limited resources in trial settings, and reluctance from pharmaceutical companies to collect smoking data due to concerns that it may affect drug approvals. However, the authors argued that omitting to record smoking status increases the risk of skewing trial results, particularly if tobacco use varies across treatment groups.
hey referenced past recommendations, including the 2020 US Surgeon General’s report and a US FDA–AACR–IASLC workshop, both of which urged structured tobacco-use assessment in trials.
The authors also noted the rise of e-cigarettes and recommended recording their use, even though the effects seem less severe than those of cigarette smoking. They pointed to examples in Canada, Australia, and the US where cancer centres routinely integrate smoking cessation discussions during registration.
“Capturing smoking status in clinical trials should no longer be considered optional; it should be regarded as an essential core element of cancer research,” the commentary concluded.
(Source: The Lancet Oncology)
