Somkers who are diagnosed with lung cancer can improve their survival chances if they quit smoking even at this stage , doctors said.
Among those smokers who quit swiftly after diagnosis, 63-70 percent were still alive after five years, a benchmark of survival in cancer research, compared with only 29-33 percent among those who continued to smoke, they said in an online report published by the British Medical Journal (BMJ).
The study, carried out by scientists at Birmingham University, central England, entailed a review of 10 published studies into smoking and cancer survival.
The authors speculate that tobacco smoke may accelerate progression of a tumour, although further work is needed to confirm this.
In any case, they say, the study says that it could be worthwhile for doctors to encourage smokers to give up their habit when diagnosed with early-stage lung cancer.
The link between lung cancer and smoking has been established for more than half a century. Lifelong smokers face a 20-fold risk of developing a primary lung tumour compared with non-smokers, according to a 2003 study.