Background: Combination therapy with exemestane and everolimus prolongs progression-free survival in patients with metastatic breast cancer but carries significant and novel toxicities with up to 21% of patients ceasing treatment due to adverse events.

Aims: To assess the rate of adverse events in metastatic breast cancer patients commencing exemestane and everolimus combination treatment in the Western Sydney Oncology Network. 

Methods: Over a period of 12 months, thirty-three women on combination therapy were identified. Adverse events were identified as documented in the medical records. The records held by the Clinical Nurse Consultant were analysed for additional adverse events. Maximum follow-up is 18 months.

Results: In a more heavily pre-treated population than in previously published trials, 50% of patients ceased therapy due to toxicities associated with treatment and 50% patients ceased due to progressive disease.  The incidence of all grades of stomatitis was 55% with grade 3/4 toxicity 6%. The incidence of pneumonitis was 15%. A total of 61% patients required dose interruptions or reductions whilst on combination therapy.

Conclusions: In a more heavily pretreated population of metastatic breast cancer patients than in the reported BOLERO-2 study, more patients ceased treatment due to toxicities.  Our population experienced less headache, diarrhea, rash, weight loss and anorexia than reported in the BOLERO-2 trial.  Excepting this, our data was similar to that in the published trial.