Maintaining Dose Intensity of Adjuvant Chemotherapy in Older Patients With Breast Cancer

Maintaining the relative dose intensity (RDI) of adjuvant chemotherapy at ≥ 85% has been associated with improved treatment outcomes in early-stage breast cancer (ESBC). Increasing evidence has suggested that patients aged ≥ 65 years can maintain the optimal RDI for standard chemotherapy regimens. The present study investigated the RDI of newer adjuvant chemotherapy regimens in this demographic.

We retrospectively analyzed the data from 281 patients aged ≥ 65 years with a diagnosis of ESBC who had received adjuvant chemotherapy across 3 sites in Queensland, Australia from 2010 to 2015. The primary endpoint was the proportion of patients who had received an RDI of ≥ 85%.

The median age at diagnosis was 68 years (range, 65-85 years), with 36.3% aged > 70 years. The patient characteristics included tumor stage T3 or T4 in 17% and node-positive disease in 60%. The common chemotherapy regimens included docetaxel/cyclophosphamide (23%), 5-fluorouracil/epirubicin/cyclophosphamide plus docetaxel or paclitaxel (17%); Adriamycin/cyclophosphamide/weekly paclitaxel (38%); and docetaxel/carboplatin/trastuzumab (11%). Primary (15%) and secondary (54%) granulocyte colony-stimulating factor (G-CSF) was used. An RDI of ≥ 85% was achieved in 63% of the patients. Significant associations were noted between a reduced RDI and age ≥ 70 years (P < .001), Charlson comorbidity index ≥ 1 (P = .043), initial dose reductions (P = .01), secondary G-CSF use (P = .45), hospital admission (P < .001), and febrile neutropenia (P = .007). Treatment-related toxicities were the most common reason for noncompletion, with high rates of hospital admissions (46%) and febrile neutropenia (22%).

Our findings suggest that patients aged ≥ 65 years with ESBC can maintain an optimal RDI with modern chemotherapy regimens. Appropriate geriatric assessment and the use of supportive measures such as G-CSF could better assist select groups to maintain an optimal dose intensity.