Acute toxicity and tolerability of anthracycline-based chemotherapy regimens in older versus younger patients with breast cancer: real-world data.

OBJECTIVES To compare the non-cardiac acute toxicity and tolerability profile of anthracycline-based regimens between older versus younger women diagnosed with breast cancer in a real-world setting. METHODS Retrospective cohort of female patients diagnosed with breast cancer and treated with neoadjuvant or adjuvant anthracycline-based regimens between 2017 and 2019. Patients were grouped in young versus older, using an age of 65 as cut-off. Differences in non-cardiac acute toxicity and change in treatment plan were examined. RESULTS Among the 559 patients, 19.5% were aged ≥ 65 years. Regimens used were fluorouracil, epirubicin, and cyclophosphamide in 56.2% of patients, doxorubicin and cyclophosphamide in 33.3%, and epirubicin and cyclophosphamide in 10.5%; there were no differences in incidence of grade 3 or 4 toxicities between regimens (p = 0.184). Acute grade 3 or 4 toxicities occurred more frequently in the older group (33.9% versus 10.7%, p < 0.0001, OR 4.304, 95%-CI [2.619-7.073]). Delay of at least one chemotherapy cycle due to toxicity occurred more frequently in the older group (24.8% versus 9.3%, p < 0.0001, OR 3.199, 95%-CI [1.867-5.481]). Early termination of treatment also occurred more frequently in the older group (11.9% versus 1.6%, p < 0.0001, OR 8.571, 95%-CI [3.331-22.048]). CONCLUSION Although acute grade 3 or 4 toxicities were more frequent in older patients, which resulted in increased cycle delay and/or premature termination of treatment, overall treatment was still reasonably well-tolerated, with 88.1% of older patients completing the planed anthracycline regimen.