Smoking is associated with prostate cancer mortality. The Scandinavian smokeless tobacco product snus is a source of nicotine but not the combustion products of smoke, and has not been studied with respect to prostate cancer survival. The study is nested among 9,582 men with incident prostate cancer within a prospective cohort of 336,381 Swedish construction workers. Information on tobacco use was collected at study entry between 1971 and 1992, and categorized into (1) never users of any tobacco, (2) exclusive snus: ever users of snus only, (3) exclusive smokers: ever smokers (cigarette, cigar, and/or pipe) only, and (4) ever users of both snus and smoking. Hazard ratios for prostate cancer-specific and total mortality for smoking and snus use based on Cox proportional hazards models adjusted for age, calendar period at diagnosis, and body mass index at baseline. During 36 years of follow-up, 4,758 patients died - 2,489 due to prostate cancer. Compared to never users of tobacco, exclusive smokers were at increased risk of prostate cancer mortality (HR 1.15, 95% CI: 1.05-1.27) and total mortality (HR 1.17, 95% CI: 1.09-1.26). Exclusive snus users also had increased risks for prostate cancer mortality (HR 1.24, 95% CI: 1.03-1.49) and total mortality (HR 1.19, 95% CI: 1.04-1.37). Among men diagnosed with non-metastatic disease, the HR for prostate cancer death among exclusive snus users was 3.17 (95% CI: 1.66-6.06). The study is limited by a single assessment of tobacco use prior to diagnosis. Snus use was associated with increased risks of prostate cancer and total mortality among prostate cancer patients. This suggests that tobacco-related components such as nicotine or tobacco-specific carcinogens may promote cancer progression independent of tobacco's combustion products. This article is protected by copyright. All rights reserved.
International journal of cancer. 2016 Sep 01 [Epub ahead of print]
Kathryn M Wilson, Sarah C Markt, Fang Fang, Caroline Nordenvall, Jennifer R Rider, Weimin Ye, Hans-Olov Adami, Pär Stattin, Olof Nyrén, Lorelei A Mucci
Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA USA., Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden., Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden., Department of Epidemiology, Boston University School of Public Health, Boston, MA USA.