Breast cancer occurs in 25% over the age of 70 years. This subgroup is not well represented in adjuvant trials. Retrospective analysis has suggested that patients tolerate older adjuvant chemotherapy well but this has not been assessed in newer chemotherapy regimens. The aim of this study was to evaluate the tolerability and feasibility of newer adjuvant chemotherapy in breast cancer patients aged 65 years and older.
We conducted a retrospective study for patients aged 65 years and older who underwent adjuvant chemotherapy at Gold Coast University Hospital from 2009 to 2014. The primary outcome was maintaining a Relative Dose Intensity (RDI) over 85% calculated via the Hyrniuk method. Secondary outcomes included toxicity to chemotherapy.
A total of 103 patients were included in our study. Chemotherapy regimens included TC (25%), FEC-D (25%) AC-T (27%) and TCH(14%). All cycles of chemotherapy was completed in 64% of patients and 56% completed chemotherapy with an RDI greater than 85%. Admissions to hospital were recorded for 46%, and dose delays secondary to toxicity occurred in 26%. G-CSF was administered in 73% of all patients. The most common cause of discontinuation of chemotherapy was neuropathy (28%) and infective complications (19%). A statistically higher RDI was seen in patients younger than 70 years in comparison to older (Mean RDI 83 v 72, p=0.023), in the absence of hospital admission (Mean RDI 87 v 72, p=0.001) and the use of G-CSF (Mean RDI 84 v 68, p=0.002)
It is possible to complete chemotherapy and maintain dose intensity of over 85% in older patients. However, tolerability remains sub-optimal, as reflected by chemotherapy discontinuation and dose reduction secondary to toxicity. Comprehensive geriatric assessment may help select appropriate patients for adjuvant chemotherapy, while better supportive cares such as primary G-CSF may enable higher RDI while maintaining safety.