Incidence and Predictors of Low Chemotherapy Dose-Intensity in Aggressive Non-Hodgkin's Lymphoma: A Nationwide Study

Abstract

Purpose To assess the incidence of and risk factors for reduced relative dose-intensity (RDI) in patients treated with chemotherapy for aggressive non-Hodgkin's lymphoma (NHL). Methods A nationwide survey was conducted of 567 oncology practices with data extracted from the records of 4,522 patients with aggressive NHL treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP); CHOP-rituximab (CHOP-R); or cyclophosphamide, mitoxantrone, vincristine, and prednisone (CNOP). The primary outcome was the average RDI for each regimen based on both planned and reference standards. Other assessments included the incidence of febrile neutropenia and patterns of colony-stimulating factor (CSF) use, as well as the average RDI in high-risk subgroups. Results Dose reductions ≥ 15% occurred in 40% of patients and treatment delays ≥ 7 days occurred in 24% of patients, resulting in 53% and 48% of patients receiving an RDI less than 85% of the minimum six-cycle and National Comprehensive Cancer Network guideline standards, respectively. Reduced RDI was more prevalent in older patients, with 60% of patients older than 60 years receiving RDI less than 85%. Multivariate analysis identified several independent predictors for reduced RDI, including age older than 60 years, advanced disease stage, poor performance status, and no prophylactic CSF use. Age was no longer a significant risk factor in patients who received prophylactic CSF. Conclusion Patients with aggressive and potentially curable NHL treated with CHOP, CHOP-R, or CNOP frequently receive reduced RDI. Predictive models based on the risk factors identified for reduced RDI should enable the targeted use of appropriate supportive care, facilitating the delivery of full chemotherapy doses on schedule.