Abstract P1-17-09: Cardiotoxicity and overall safety profile of adjuvant chemotherapy in elderly breast cancer patients: A cohort study
Authors: Gervaso Lorenzo , Zanuso Valentina , Cefalì Marco , Fregoni Vittorio , Porta Camillo 
Published: March 2020

Abstract
Background: around 40% of breast cancers are diagnosed in patients over 65-years old and more than one third of them receive indication to adjuvant chemotherapy. This population has, generally, more comorbidities, worst performance status and is more likely to suffer chemotherapy side effects compared to younger patients. The higher rate of toxicities, including cardiologic toxicity straight related to chemo-immunotherapy, often leads clinicians to reduce doses, delay schedules or even prematurely interrupt treatments, which negatively affect survival. The aim of this study was to evaluate the rate of main toxicities in this specific setting, the rate of discontinuation and eventually their correlation with outcomes.Methods: we conducted a retrospective cohort study enrolling consecutive out-setting breast cancer patients treated at the medical oncology unit of ICS Maugeri Hospital, University of Pavia, from 01/2010 to 12/2017. Inclusion criteria were female sex, age ≥ 65 years, ECOG PS 0-2 and indication to adjuvant chemotherapy after multidisciplinary tumor board evaluation. Regimens and adherence to chemotherapy, intended as dose reductions or early interruptions have been collected for each patient by review of electronic medical records, as well as side effects (cardiologic, hematologic and gastrointestinal) occurred during the treatment period. Cardiologic toxicity was defined as a reduction &gt;10% in EF without symptoms or &gt;5% when associated with clinical manifestation, below the threshold of 55%. Rates of hematologic and cardiologic toxicity and rate of chemotherapy dose reduction/ discontinuation have been calculated. Progression free survival (PFS) were performed by Kaplan-Meier and evaluated for its association with chemotherapy reduction/suspension and toxicities occurrence using Log-rank test. Results: the study population included 128 women, with a median age of 71 years (range 65-81). The most used chemotherapy regimen was sequential antracyclines plus taxanes (61/128, 47.7%) followed by antracyclines monotherapy in 33 patients (25.8%) and taxanes monotherapy in 22 (17.2%). In our cohort, 19 patients experienced cardiologic toxicity (14.8 %) and almost one third of the study population hematologic one (38/128, 29.7%). Dosage of chemotherapy, compared to first cycle, was reduced in 23 patients (18.0%), while 14 of the total (10.9%) prematurely interrupted the adjuvant treatment. Median PFS in the whole cohort was 92 months (95% CI 86.6 - 99.1). Dose reduction or premature interruption of the treatment for any reasons were associated with numerically worse PFS [78.2 months (95% CI 61.2 - 95.1) vs 94.8 months (95% CI 88.4 - 101.3) p = 0.10). In addition, similarly, patients who experienced cardiologic toxicity had worst PFS [75.6 months (95% CI 52.5 - 98.6) vs 93.5 months (95% CI 87.1 - 99.9) p = 0.41). Conclusion: cardiologic toxicity affected 15% of patients in our over 65-years population and reduction or discontinuation of adjuvant chemotherapy due to side effects happened in nearly 30%, both potentially worsening outcomes. Further work is required to improve patient selection and identify early cardiac damage biomarkers in order to successfully complete adjuvant treatment and minimize side effects.
Citation Format: Lorenzo Gervaso, Valentina Zanuso, Marco Cefalì, Vittorio Fregoni, Camillo Porta. Cardiotoxicity and overall safety profile of adjuvant chemotherapy in elderly breast cancer patients: A cohort study [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-17-09.