Clinical Characteristics and Prognostic Factors Associated with Herpes Zoster in Patients with Malignant Tumors: A Systematic Review and Meta-analysis

Background: Herpes zoster (HZ) is a common complication in patients with malignant tumors (MT), impacting prognosis. Immunocompromised states due to malignancy or treatment increase HZ risk. However, comprehensive assessments of HZ's clinical features and its impact on prognosis in these patients are limited, general conclusions are challenging, prompting a systematic review and meta-analysis to better understand the relative risk of HZ in malignancy. Objective: To assess the clinical features and prognostic factors of HZ in cancer patients through systematic review and meta-analysis. The study aimed to calculate the relative risk of HZ in malignancy and analyze factors affecting prognosis, such as age, gender, tumor type, and treatment. Methods: A systematic search in PubMed (2016-2024) identified studies on HZ and malignancy. Two reviewers independently screened and selected studies, extracting data on study characteristics, population demographics, and outcomes. Statistical heterogeneity across the studies was addressed using random-effects models, while subgroup analyses were performed to identify potential sources of heterogeneity. Results: Out of the 633 records reviewed, 13 studies satisfied the eligibility criteria and were incorporated into the meta-analysis. The combined relative risk for any type of cancer was found to be 1.82(95% CI: 1.29,2.57). The combined relative risk for any solid tumors was 1.63(95% CI: 1.08,2.46). The combined relative risk for any haematological cancer was 3.43(95% CI: 1.33,8.86). The combined analysis of all treatment modalities (including Radiotherapy, Chemotherapy, Immunosuppression, HSCT) shows a significant overall effect with a risk ratio of 1.78(95%CI: 1.59,2.00). Conclusion: Cancer patients have increased HZ risk due to immunosuppression from the malignancy and its treatment, especially in hematological cancers and those undergoing stem cell transplantation.