Predictors of toxicity and toxicity profile of adjuvant chemotherapy in elderly breast cancer patients.

Women older than 70 years have been underrepresented in breast cancer adjuvant chemotherapy trials due to concerns about toxicity, safety and tolerance of chemotherapy. The aim of our study was to assess the tolerance of chemotherapy in older women with breast cancer and determine patterns of toxicity including the impact of age, chemotherapy regimen, functional status and comorbid conditions on this toxicity. We retrospectively reviewed the charts of early stage (stages 1 and 2) breast cancer patients older than 70 years from 1998 to 2004. A total of 62 patients, with mean age of 74.3 years, were identified. Chemotherapy was completed in 89% patients. Overall 79% completed chemotherapy without any significant side-effects, dose reductions, or breaks during chemotherapy. Using logistic regression model increasing age was not associated with early termination of chemotherapy (p = 0.19, OR: 0.868, 95% CI: 0.7-1.076). However, increasing age, lower functional status, and higher comorbidity index scores were associated with reduction in dose and breaks in chemotherapy. None of the patients who received pegfilgrastim prophylactically developed high-grade neutropenia. Our study suggests that adjuvant chemotherapy is safe in elderly patients. Older patients with good functional status and low comorbidity index scores tolerate chemotherapy as well as the younger patients. Prophylactic use of pegfilgrastim may reduce occurrence of severe neutropenia and related toxicity such as febrile neutropenia in the elderly patient.