A model to predict delivery of reduced chemotherapy dose intensity in the first three cycles of treatment among patients with non-Hodgkin's lymphoma and breast cancer

Abstract

6100 Background: Reduction of chemotherapy dose intensity is common among patients receiving treatment for non-Hodgkin's lymphoma (NHL) and breast cancer. A recent publication suggests that neutropenia is a cause of dose modifications, and that maintaining chemotherapy dose intensity in the initial cycles may be associated with improved outcomes. We evaluated possible risk factors associated with delivery of reduced chemotherapy dose intensity in the first 3 cycles of treatment among a sample of patients with NHL or breast cancer. Methods: A historical case series of 1617 patients (704 NHL and 913 early-stage breast cancer) who received initial chemotherapy at 16 community and academic oncology practices between 1991 and 1999 were studied. Reduced average relative dose intensity (ARDI) was defined as at least a 20% or 15% reduction in dose intensity for NHL and breast cancer patients, respectively. Stepwise logistic regression was used to select risk factors significantly associated with a reduction in ARDI. Results: 427 of 1617 patients (26%) received reduced ARDI within the first 3 cycles of chemotherapy. Factors significantly associated with delivery of reduced ARDI in a multiple logistic regression model included age greater than or equal to 65 years (odds ratio [OR] 2.4; 95% CI 1.8–3.2), presence of heart, renal, or hepatic comorbidity (OR 2.2; 95% CI 1.6–3.2), low body surface area (OR 1.3; 95% CI 1.1–1.7), and no preemptive growth factor in cycle 1 (OR 1.7; 95% CI 1.0–2.6). Patients with NHL were less likely to have a reduction in ARDI (OR 0.6; 95% CI 0.4–0.8). Conclusions: Increased age, comorbidity (heart, renal or hepatic), low body surface area, and no preemptive growth factor in cycle 1 were associated with increased risk for delivery of reduced chemotherapy dose intensity in cycles 1 through 3 after controlling for differences in diagnosis. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Amgen Amgen, Inc.; Schering-Plough Amgen, Inc. Amgen, Inc.