Smokeless tobacco product may increase mortality rate in patients with prostate cancer

Abstract

Use of snus, a smokeless tobacco product used mainly in Sweden but also sold in the United States, may increase the risk that men with prostate cancer will die of the disease and that they will die prematurely of any cause, according to a new study by researchers at the Harvard T.H. Chan School of Public Health in Boston, Massachusetts.1 The study builds on previous studies that demonstrated an increased risk of death from prostate cancer in smokers with the disease. The latest findings suggest that nicotine or other non-combustion-related components of tobacco may play a role in the progression of prostate cancer. Snus, which to the authors' knowledge had not previously been studied in relation to prostate cancer survival, is a powdered product often sold in teabag-like sachets. It is placed under the upper lip for long periods and contains nicotine but no combustion components. Researchers analyzed health data gathered from 336,381 Swedish construction workers during preventive checkups between 1971 and 1992, including a tobacco use questionnaire from each man's initial checkup. Of the men studied, 9582 later developed prostate cancer, approximately half of whom died during the follow-up period. Among that group, 2489 men died of prostate cancer. Snus users who did not smoke were found to have a 24% increased risk of dying of the disease and a 19% increased risk of dying during the study period of any cause compared with those who never used tobacco. Among the men whose cancer had not spread, the risk of death from prostate cancer for snus-only users was found to be 3 times higher than for those who had never used tobacco. Animal studies have produced some evidence that nicotine can promote cancer progression, and snus users have high blood levels of nicotine, according to the study investigators. They add that snus users also are exposed to other carcinogens in tobacco, even though it is a smokeless product. For that reason, the authors say that the health effects of smokeless tobacco products should be studied carefully.