It’s Never Too Late to Quit Smoking, Researchers Say


It’s never too late to stop smoking, even for smokers already diagnosed with lung cancer, new research shows.

Meanwhile, continuing to smoke is associated with a significantly increased risk of early death from all causes including an increased risk of cancer recurrence, according to recent analysis published by the British Medical Journal.

The analysis showed a five year survival rate of 63-70% among quitters, compared with 29-33% among those who continued to smoke. Put simply, about twice as many quitters would survive for five years compared with continuing smokers wrote Amanda Parsons, a research fellow at the University of Birmingham in England and one of the authors of the systematic review of published trials of smokers and smoking cessation.

The authors also suggested that their findings “support the hypothesis that continued smoking affects the behavior of a lung tumor” though which specific component of tobacco smoke is the culprit is unknown.

In an accompanying editorial, Dr. Tom Treasure, a cardiothoracic surgeon at University College London, and psychiatrist Janet Treasure, also from University College, wrote that the new review demonstrated that the impact of continued smoking is so large that both patients and “those caring for them should be given this information because the potential benefit is great.”

This is the first review of studies to measure the effects of continued smoking after diagnosis of lung cancer. Worldwide, lung cancer is the most commonly diagnosed form of cancer. Smoking increases the risk of developing a primary lung cancer; lifelong smokers have a 20-fold increased risk compared with non-smokers. The researchers at the University of Birmingham analyzed the results of 10 studies that measured the effect of quitting smoking after diagnosis of lung cancer on prognosis. Differences in study design and quality were taken into account to minimize bias.