Chemotherapy-induced cardiotoxicity in cancer patients: an observational study at an Oncology reference hospital from southeastern Brazil.

to assess the clinical, inflammatory and electrocardiographic profile of cancer patients undergoing the Pre-chemotherapy phase, with the purpose of early identifying cardiovascular toxicity indicative signs. an observational and cross-sectional study, conducted between November2022 and December2023 with adult cancer patients in stagesI toIII treated at a hospital from southern Brazil. Sociodemographic, clinical and tumor-related data were collected, in addition to laboratory and electrocardiographic tests performed before the first chemotherapy infusion. Descriptive analyses were carried out in the Rsoftware. the participants were 84 patients, mostly women (72.6%) with breast cancer diagnoses(57.1%). Prevalence of systemic inflammation was verified, with high C-reactive protein in 35.7% and increased neutrophil-lymphocyte and platelet-lymphocyte ratios in 23.5% and 27.2%, respectively. A significant association was observed between high Body Mass Index and T-wave alterations (p=0.005). Although 10 patients presented prolonged corrected QT intervals, no other statistically significant associations were identified. the pre-chemotherapy phase revealed relevant inflammatory and electrocardiographic alterations, even in the absence of installed cardiotoxicity. The findings reinforce the importance of baseline cardiovascular evaluations and of multi-professional follow-up in Cardio-Oncology, especially for patients with modifiable risk factors. Longitudinal studies are recommended to elucidate the clinical and prognostic evolution of these alterations.