Herpes Zoster in Breast Cancer Patients: A 15-Year Experience from a Single Tertiary Referral Center in Korea

Background: Breast cancer is the second most common cancer and the most common cause of cancer deaths in Korean women. Although tumor-induced mediators and cancer therapy can suppress cell-mediated mununity, the concurrence of herpes zoster in breast cancer patients has not been well-recognized. Objective: This study aimed to delineate the characteristics of herpes zoster in patients with breast cancer, particularly its association with patient age and breast cancer severity, treatment, and clinical course. Methods: We retrospectively reviewed the medical records of breast cancer patients at a tertiary referral center in Korea from January 2003 to June 2018, identified patients with a subsequent diagnosis of herpes zoster, and analyzed their cUnical characteristics. Results: Among 8,124 patients with breast cancer, 2.04% further developed zoster during a median 31-month follow-up period. Age at the diagnosis of breast cancer was higher in the zoster group than in the no zoster group. Cytotoxic chemotherapy and radiotherapy significantly increased the risk of zoster. Tune from the diagnosis of breast cancer to zoster development was significantly shorter for invasive cancers than for in-situ cancers, with higher risk in the initial 2 years from the cancer diagnosis. Conclusion: This study showed that breast cancer patients are at an increased risk of zoster, particularly in the time following cancer diagnosis. Therefore, a recent diagnosis of breast cancer should warrant clinical suspicion of zoster for patients with suggestive symptoms, and active management should be started.