Investigators who studied men who underwent radical treatment for prostate cancer (PCa) found that smoking duration of 10 or more years among those who had ever smoked was associated with an increased risk of biochemical recurrence of the disease, according to a new report.

“Smoking duration is a modifiable risk factor and could be used to identify the ever-smokers at highest risk for prostate cancer recurrence,” Saira Khan, PhD, MPH, of the University of Delaware in Newark, and colleagues concluded in a paper published in Annals of Epidemiology.

Dr Khan’s team conducted a prospective cohort study of 1641 men with PCa treated with radical prostatectomy or radiation. Of these men, 773 were ever-smokers. In the full cohort, the investigators found no association between ever-smoking and biochemical recurrence. Among the ever-smokers, however, smoking duration of 10 or more years vs less than 10 years was significantly associated with a 2.3-fold higher risk of biochemical recurrence after adjusting for potential confounders.
“Our results indicated that smoking duration was the strongest predictor of biochemical recurrence,” the authors wrote. “Indeed, we found that it was a stronger predictor than both packs smoked per day and pack-years smoked. This is an interesting finding, as one might expect pack-years of smoking to be the strongest predictor. Objectively, pack-years is the most comprehensive measure, incorporating both years smoked and number of cigarettes smoked per day.”

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They noted that it is possible that smokers with PCa can recall dates of smoking initiation and cessation more accurately than the average number of packs smoked per day.

Reference

Kahn S, Thakkar S, Drake B. Smoking history, intensity, and duration and risk of prostate cancer recurrence among men with prostate cancer who received definitive treatment [published online September 6, 2019]. Ann Epidemiol. doi: 10.1016/j.annepidem.2019.08.011