July 1, 2005

Smoking and hepatitis C up risk of lymphoma

By Megan Rauscher

NEW YORK (Reuters Health) - Results of an Italian study
confirm that heavy smoking doubles the risk of developing
non-Hodgkin lymphoma (NHL), a cancer of the lymph nodes. The
study also shows that hepatitis C virus (HCV)-positive
individuals who are heavy smokers have an approximately 4-fold
elevated risk of developing NHL.

According to researchers, about 5 percent to 10 percent of
NHL cases could be prevented by persuading people to quit
smoking and by integrated policies and health programs aimed at
reducing HCV infection.

"Smoking is a well-documented risk factor for several
cancers, but the role of cigarette smoking in the etiology of
NHL is inadequately understood," lead researcher Dr. Renato
Talamini from the National Cancer Institute in Aviano told
Reuters Health. HCV infection has been associated with NHL, he
noted, but the interplay between tobacco use and HCV has not
been studied.

Talamini and colleagues studied relationships between HCV,
smoking habits and NHL in 225 consecutive patients who were
hospitalized with a new diagnosis of NHL and 504 matched
control patients who were hospitalized for a wide range of
acute conditions not related to cancer or tobacco.

Compared with never smokers, current smokers of 20 or more
cigarettes per day had a greater than 2-fold increased risk of
NHL, the investigators report in the International Journal of
Cancer. This finding was consistent for both sexes and all age

Being positive for HCV infection also increased the risk of
NHL significantly.

"The effects of tobacco smoking and HCV infection seemed to
act independently on NHL risk, leading to a grossly elevated
risk for heavy smokers who are HCV positive," Talamini told
Reuters Health. "Tobacco and HCV seem to act at different
stages of the process of NHL carcinogenesis."

"Health professionals could play a key role in reducing NHL
incidence in the population," Talamini contends, by promoting
healthy lifestyles and behaviors, engaging in anti-smoking
campaigns, providing support for people who are quitting, and,
in the absence of proven HCV vaccine, promoting interventions
against risky behaviors including intravenous drug use and
unprotected sexual intercourse.

SOURCE: International Journal of Cancer July 1, 2005.