Toxicity of Older and Younger Patients Treated With Adjuvant Chemotherapy for Node-Positive Breast Cancer: The Cancer and Leukemia Group B Experience

Abstract

PurposeOlder node-positive patients treated with newer adjuvant chemotherapy regimens have improvements in relapse-free and overall survival similar to younger patients. We compared toxicity of older and younger patients in three randomized trials of adjuvant chemotherapy.Patients and MethodsToxicity data were available for 93% of 6,642 patients enrolled. The three trials included: Cancer and Leukemia Group B (CALGB) 8541, a comparison of cyclophosphamide, doxorubicin, and fluorouracil in three dose schedules; CALGB 9344: cyclophosphamide and doxorubicin with or without paclitaxel; and CALGB 9741: cyclophosphamide, doxorubicin, and paclitaxel every 2 versus every 3 weeks. National Cancer Institute grade 3 to 5 toxicities were compared among age groups.ResultsSeven percent of patients (n = 458) were age 65 or older, 3% were 70 or older, 38% were 51 to 64, and 55% were 50 or younger. Twenty-four deaths (0.4%) were attributed to treatment; seven (1.5%) of 486 in patients 65 or older, 10 (0.40%) of 2,480 in patients who were 51 to 64 years, and seven (0.19%) of 3,676 occurred in patients younger than 50. In multivariate analysis, older patients were significantly more likely to have grade 4 hematologic toxicity, to have discontinued treatment for toxicity, or to have died of acute myeloid leukemia/myelodysplastic syndrome. There were no significant differences in grade 3 to 4 nonhematologic toxicity.ConclusionHealthy older patients who met the strict eligibility criteria for these trials had a higher rate of hematologic toxicity and treatment-related deaths than younger patients, but no increase in nonhematologic toxicity. Elderly patients treated with newer adjuvant chemotherapy regimens derive the same benefits from newer chemotherapy regimens as younger patients but should be cautioned about the increased risk of toxicity and treatment-related death.