Smoking and hepatitis C and lymphoma

Heavy smoking doubles the risk of developing non-Hodgkin lymphoma (NHL), a cancer of the lymph nodes. Hepatitis C virus (HCV)-positive individuals who are heavy smokers have an approximately 4-fold elevated risk of developing NHL. 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.HCV infection has been associated with NHL, he noted, but the interplay between tobacco use and HCV has not been studied. Researchers from the National Cancer Institute studied relationships between HCV, smoking habits and NHL in 225 consecutive patients who were hospitalised with a new diagnosis of NHL and 504 matched control patients who were hospitalised 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. This finding was consistent for both sexes and all age groups. 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. 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 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.