Herpes zoster, or shingles, does not increase the risk of cancer in the general population, according to a study in CMAJ (Canadian Medical Association Journal).

Although herpes zoster is more common in patients with cancer than in those without, it is unknown whether the risk of cancer is increased for people with herpes zoster. Several studies have indicated an association although most were conducted in western countries.

A large study of 35 871 patients in Taiwan with newly diagnosed herpes zoster found no increased risk of cancer in patients with herpes zoster.

"We found no overall increased risk of cancer among patients with herpes zoster compared with the general population, regardless of sex, age or years of follow-up," writes Dr. Yi-Tsung Lin, Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, with coauthors.

The study included data on other illnesses in patients with herpes zoster, such as diabetes, chronic obstructive lung disease, autoimmune disease and heart disease. Most previous studies did not adjust for comorbidity.

"These findings suggest that the extensive investigations for occult cancer at the time of diagnosis of herpes zoster or enhanced surveillance for cancer after such a diagnosis is unnecessary," conclude the authors.