Herpes zoster as a marker of underlying malignancy

BACKGROUND Both herpes zoster and malignancy are associated with immunosuppression. However, the association between herpes zoster and the subsequent diagnosis of malignancy is unclear. We undertook this study to assess whether a diagnosis of herpes zoster is a risk factor for subsequent malignancy. METHODS For this matched retrospective cohort study, a physician billing database was used to identify individuals 18 years of age or older with a diagnosis of herpes zoster and no prior diagnosis of cancer or HIV infection. Individuals with a herpes zoster diagnosis were matched one-to-one to individuals without a herpes zoster diagnosis, and both groups were examined for up to 5 years for diagnosis of cancer. RESULTS A total of 542,575 individuals with a diagnosis of herpes zoster were identified. Compared with matched controls, these patients were more likely (p < 0.001) to have a history of myocardial infarction, asthma, congestive heart failure, chronic obstructive pulmonary disease, diabetes mellitus, and hypertension. The incidence of cancer was significantly greater among individuals with herpes zoster than among those without herpes zoster, for both men and women and across all time intervals studied (up to 5 years). The greatest adjusted hazard ratio was seen 180 days after a herpes zoster diagnosis (1.19, 95% confidence interval 1.12-1.25); the hazard ratio decreased as the time from herpes zoster diagnosis increased. Lymphoma was the type of cancer with the greatest relative increase in incidence following diagnosis of herpes zoster. INTERPRETATION There is a risk of malignancy following an episode of herpes zoster in both men and women and in all age groups 18 years and over. The risk is greatest during the first 180 days following the diagnosis of herpes zoster.