medwireNews: Herpes zoster infection, or shingles, is not associated with cancer, show results from a study published in the Canadian Journal of Medicine.

The researchers hope that their findings may allay fears that patients with herpes zoster are at increased risk for cancer compared with the general population.

Yi-Tsung Lin (Taipei Veterans General Hospital, Taiwan) and colleagues searched the National Health Insurance Research Database in Taiwan for patients diagnosed with herpes zoster between 2000 and 2008.

In total, 35,871 people, aged a median of 52 years, were newly diagnosed with shingles during 2000 to 2008. During a mean follow-up period of 3.68 years, 895 also had a diagnosis of cancer.

When compared with the incidence in the general population, patients with herpes zoster were not at increased risk for cancer (incidence ratio=0.99).

Further analysis in subgroups sorted by gender, age, and years of follow up also failed to reveal any association.

Lin and team acknowledge that their study was subject to some limitations. For example, while they did adjust for presence of comorbid conditions such as diabetes, autoimmune disease, and heart disease, common risk factors for cancer such as obesity, smoking, alcohol use, and family history of cancer could not be assessed.

In addition, they say that a follow-up period longer than 9 years (the maximum observed in this study) may be needed for detection of some types of cancer.

Previous case series and results from a cohort study have shown that patients with cancer, particularly skin and hematologic cancers, have a higher incidence of herpes zoster than those without the condition, leading to fears that having shingles may increase a person's risk for cancer. However, the findings from the current study suggest that these fears may be unfounded.

The results make it likely that "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 Lin et al.

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