Impact of neoadjuvant chemotherapy and pathological complete response on eligibility for breast-conserving surgery in patients with early breast cancer: A meta-analysis

Abstract

PurposeWe conducted a meta-analysis of randomised trials evaluating pathological complete response (pCR) and surgical outcomes after neoadjuvant systemic therapy (NST) in patients with early breast cancer (EBC). Patients and methodsThe primary outcome was breast-conserving surgery (BCT) rate. Secondary outcomes were pCR rate and association to BCT. Meta-analyses were performed using random effects models that use inverse-variance weighting for each treatment arm based on evaluable patients. Point estimates are reported with 95% confidence interval (CI), and p < 0.05 was considered statistically significant. ResultsThirty-six studies were identified (N = 12,311 patients). We selected for the analysis 16 of 36 studies reporting both pCR and BCT for at least one treatment arm. Arms per study ranged from one to six; 42 independent units were available to evaluate the association between pCR and BCT. BCT rate ranged 5–76% across arms with an average BCT of 57% (95% CI 52–62%). Significant heterogeneity was observed among the trials (Cochrane Q = 787, p < 0.001, I2 = 97%). In the meta-regression model, BCT rates were not significantly associated with year of first patient-in (p = 0.89), grade (p = 0.93) and hormone-receptor status (p = 0.39). Clinical N-stage (p = 0.01) and human epidermal growth factor receptor (HER2) status (p = 0.03) were significantly associated with BCT. pCR rate ranged 3–60% across studies. The average pCR across all study arms was 24% (95% CI 19–29%). No association was observed between pCR rate in a study arm and the resulting BCT rate in a univariate model (p = 0.34) nor after adjusting for HER2 and clinical nodal status (p = 0.82). In the subset of 14 multi-arm studies, no significant association was seen between the differences in pCR and BCT between treatment arms (p = 0.27). ConclusionspCR does not increase BCT in patients receiving NST for EBC.