Hospitalization and Mortality in Cancer Patients with Dengue Fever: A Cohort Study from a Brazilian Cancer Center.

Individuals undergoing cancer treatment represent a vulnerable group either residing in or traveling to dengue endemic regions. Their immunosuppressed state may impair viral clearance, potentially exacerbating disease progression. Additionally, delayed diagnosis may occur because of atypical or masked clinical presentations. In 2024, Brazil faced an unprecedented number of dengue infections. We performed a retrospective observational study conducted at a Brazilian cancer center, an outpatient and inpatient facility, located in São Paulo to evaluate clinical and characteristics of patients with dengue and prior diagnosis of cancer, identify risk factors associated with hospitalization, and determine risk factors associated with in-hospital death. Univariate analyses were performed using the Fisher test or the χ2 test, and logistic regression was conducted for the multivariate analysis. A total of 150 patients with diagnoses of dengue and cancer were included in the study. Ninety-eight patients (65.3%) had active cancer or were undergoing oncological treatment. Sixty-nine patients (46%) required hospitalization, with an average length of stay of 9.8 days. Thirteen patients (8.7%) were admitted to the intensive care unit, and five patients (3.3%) died of dengue-related complications. Arterial hypertension (P = 0.001) and elevated liver enzymes (P = 0.004) remained independent risk factors for hospitalization. Multivariate logistic regression did not identify statistically significant predictors for mortality. The high rate of hospitalization may reflect the impact of cancer physiopathology and chemotherapy. Preventive measures, such as early vaccination before starting chemotherapy, should be advised.