Risk factors for varicella zoster disseminated infection among adult cancer patients with localized zoster.

Varicella zoster (VZ) infection can be a highly morbid and potentially fatal disease among immunocompromised patients; 811 episodes of VZ infection among adult cancer patients seen at the Princess Margaret Hospital from 1970 to 1980, were identified. Seven hundred twelve patients with first episodes of localized VZ infection (zoster) were analyzed for potential risk factors for dissemination. Significant risk factors after univariate analysis included the diagnosis of Hodgkin's disease, decreasing age, chemotherapy within 6 months of VZ infection, and extensive tumor at initial tumor diagnosis. Complete tumor remission at the time of infection, previous radiotherapy, and breast or gynecologic cancer were associated with reduced risk in this analysis. After multivariate analysis the following factors were independently associated with increased risk: Hodgkin's disease (P less than 0.001), non-Hodgkin's lymphoma (P = 0.016), and head and neck cancer (P = 0.043). Complete tumor remission and previous radiotherapy were again related to a reduced risk of infection. This study identifies risk factors that define specific subgroups of adult cancer patients with zoster infections who are at increased risk for VZ dissemination. These factors may be useful in prospectively defining high-risk groups in the design of antiviral therapy trials and may have a role in deciding which cancer patients with zoster will benefit most from receiving antiviral therapy to prevent dissemination.