OBJECTIVES : The American Society of Clinical Oncology (ASCO) recommends prophylactic use of Granulocyte Colony Stimulating Factors (G-CSF) for febrile neutropenia. Chemotherapy dose reduction is a viable alternative that is not routinely recommended but may result in cost savings. The purpose of this study was to determine the prevalence and predictors of chemotherapy dose reduction in patients with metastatic colorectal cancer.

METHODS : Data were obtained from the electronic health records of patients who received chemotherapy at a multi-center oncology practice network between 07/012013 and 12/31/2014. Chemotherapy dose reduction was defined as ≥ 10% reduction in dose of at least one cytotoxic drug, compared to the standard or initial dose. The prevalence of chemotherapy dose reduction was evaluated. A multivariate logistic regression model was used to explore the relationships between chemotherapy dose reduction and predictors including age, gender, disease, year of diagnosis, febrile neutropenia [FN] risk, line of therapy and duration of chemotherapy treatment. Adjusted odds ratios (OR) with 95% confidence intervals (CI) were estimated.

RESULTS : Of the 508 chemotherapy regimens included in the study, 209 (41.1%) were female and the mean (SD) age was 61.2 (12.0) years. Prevalence of chemotherapy dose reduction in the cohort was 67.3% (n=342). In the multivariate analysis, FN risk, line of therapy and duration of treatment were significantly associated with chemotherapy dose reduction. Patients who received chemotherapy dose reduction were more likely to have a higher FN risk (OR=2.45; 95% CI=1.53-3.94), be on a lower line of therapy (ORs range: 7.23-10.02) and have a longer duration of treatment (ORs range: 4.75-6.99).

CONCLUSIONS : A substantial proportion of the patients received chemotherapy dose reduction. Factors identified in this study may be used to target patient sub-groups for chemotherapy dose reduction and better design evidence-based interventions. Prescribers may want to consider chemotherapy dose reduction in lieu of G-CSF for this population.