Ergun, Yakup; Ucar, Gokhan; Akagündüz, Baran

Background: The rate of pathological complete response (pCR) with both chemotherapy alone (CT) and endocrine therapy (ET) in the neoadjuvant (Na) treatment of hormone receptor (HR)-positive/HER2-negative breast cancer (BC) is unsatisfactory. Limited data on neoadjuvant concomitant chemotherapy and endocrine therapy (NaCET) are available. Research design and methods: In this meta-analysis analyzed the efficacy and safety of randomized controlled trials (RCT) comparing the use of NaCET in HR-positive/HER2-negative BC. A comprehensive search was performed on PubMed, Cochrane Library and EMBASE databases, and congress paper lists for studies published/presented until 1 December 2022. Results: Five RCTs involving a total of 630 patients were included. A pooled analysis of the five studies demonstrated that the pCR ratio was numerically higher in the NaCET arm than in the NaCT arm, but the difference was not statistically significant (6.5% vs. 3.8%; OR:1.72, 95% CI 0.82–3.62). Nonetheless, the NaCET arm exhibited a significantly higher objective response rate (ORR) (82% vs. 72.7%; OR:1.77, 95% CI 1.20–2.62). There was no difference between the arms in terms of grade 3–5 adverse events. Conclusions: In HR-positive/HER2-negative BC, NaCET significantly increases ORR without an increase in serious adverse events. Although the pCR rate increased numerically, it was not statistically significant.