Consumption of smokeless tobacco product `snus` on a regular basis may prove fatal to men with prostate cancer and can even lead them to the risk of premature death, suggests a new study led by researchers at Harvard University.

The findings, which are also influenced by previous studies showing increased risk of death from prostate cancer in smokers with the disease, suggest that nicotine or other non-combustion-related components of tobacco may play a role in prostate cancer progression.

Snus is a powdered tobacco product, often sold in teabag-like sachets, that is placed under the upper lip for extended periods.

Co-author of the study Kathryn Wilson, said, "Snus has been suggested as a less harmful alternative to smoking because it lacks the combustion products of smoking that are associated with cancer risk.

However, we found that men with prostate cancer who used snus were at increased risk of premature death.

"It contains nicotine but no combustion components, and has not been previously studied in relation to prostate cancer survival.

The researchers analyzed health data collected from Swedish construction workers during preventive health check-ups between 1971 and 1992, including a tobacco use questionnaire completed during each man`s initial check-up.

Of these men, 9,582 later developed prostate cancer. About half of the subjects died during the follow-up period--2,489 from prostate cancer.

Those who used snus but did not smoke had a 24 percent increased risk of dying from prostate cancer and a 19 percent increased risk of dying, as compared to those who never used tobacco. Among men whose cancer had not spread, increased risk of death from prostate cancer was three times higher than for never-users of tobacco.

Research associate Sarah Markt said, "There is some evidence from animal studies that nicotine can promote cancer progression, and snus users have high blood levels of nicotine. Snus users are also exposed to other carcinogens in tobacco even though it is a smokeless product."

Adding, "Taken together, this suggests that the health effects of smokeless tobacco products should be carefully studied by public health officials."

The study was published in the International Journal of Cancer.