Combined endocrine approaches vs endocrine therapy alone as first line treatment in elderly patients with hormone receptor-positive, HER2 negative, advanced breast cancer: to prescribe for the patient or the physician? A meta-analysis of phase II and III randomized clinical trials

Background Elderly patients are underrepresented in clinical study where combined endocrine strategies were compared to endocrine therapy (ET) in hormone receptors positive, HER2 negative, metastatic breast cancer. The role of the new endocrine approaches in elderly women is still unclear. Methods We performed a meta-analysis of first line phase II/III randomized trials on ET versus combined strategies considering clinical benefit and safety profile. Trials with hazard ratio (HR) for PFS in elderly patients were included. Results Overall, the meta-analysis showed a PFS advantage for the experimental arms [HR 0.77, p 0.016] with a significant high/moderate heterogeneity [I2 65.46%, p 0.005]. For patients on CDK 4/6 inhibitors and ET, HR was 0.57 (p < 0.0001), with low heterogeneity [I2 0.0001%, p 0.96]. Hematological adverse events, as well as diarrhea with Abemaciclib, were significantly higher in elderly population. Conclusions The magnitude of PFS benefit due to the combined strategies in elderly patients is similar to those reported in the overall clinical trial population. Adding CDK4/6 inhibitors to ET significantly prolongs PFS, even if toxicity profile have to be carefully considered. Future trials should be designed taking into account patients' age, geriatric assessment and comorbidity.