Neoadjuvant Chemotherapy or Endocrine Therapy for Invasive Ductal Carcinoma of the Breast With High Hormone Receptor Positivity and Human Epidermal Growth Factor Receptor 2 Negativity
Authors: Jiaqiang Zhang, Chang-Yun Lu, Ho-Min Chen, Szu-Yuan Wu
Journal: JAMA Network Open (2021)

<h3>Importance</h3> Although neoadjuvant endocrine therapy (NET) is an alternative to chemotherapy for strongly hormone receptor (HR)–positive and human epidermal growth factor receptor 2 (<i>ERBB2</i>)–negative breast cancer, evidence is currently lacking regarding the probable survival outcomes of NET in comparison with those of neoadjuvant chemotherapy (NACT) for this cancer. <h3>Objective</h3> To evaluate all-cause mortality among patients with strongly HR-positive and<i>ERBB2-</i>negative breast cancer treated with NET vs NACT. <h3>Design, Setting, and Participants</h3> This cohort study included patients with a diagnosis of invasive ductal carcinoma (IDC) with strong HR positivity and<i>ERBB2 </i>negativity, treated between January 1, 2009, and December 31, 2016, with follow-up from the index date (ie, date of IDC diagnosis) to December 31, 2018. The data came from the Taiwan Cancer Registry Database. Data were analyzed from January to November 2020. <h3>Exposures</h3> NET vs NACT for IDC with strong HR positivity and ERBB2 negativity. <h3>Main Outcomes and Measures</h3> The primary end point was all-cause mortality. Propensity score matching was performed, and Cox proportional hazard models were used to analyze all-cause mortality among patients undergoing different neoadjuvant treatments. <h3>Results</h3> A total of 640 patients (297 [46.4%] aged 20-49 years) undergoing NET (145 patients [22.7%]) or NACT (495 patients [77.3%]) were eligible for further analysis. In the multivariate Cox regression analyses, the adjusted hazard ratio (aHR) for all-cause mortality among the NET cohort compared with the NACT cohort was 2.67 (95% CI, 1.95-3.51;<i>P</i> &lt; .001). The aHRs for age were 1.13 (95% CI, 1.03-2.24), 1.25 (95% CI, 1.13-2.45), and 1.37 (95% CI, 1.17-3.49) for all-cause mortality among patients aged 50 to 59, 60 to 69, and 70 years or older, respectively, compared with those aged 20 to 49 years (<i>P</i> = .002); the aHR for all-cause mortality among premenopausal women was 1.35 (95% CI, 1.13-1.56) compared with postmenopausal women (<i>P</i> &lt; .001); and that of patients with a Charlson Comorbidity Index score of 2 or greater was 1.77 (1.37-2.26) compared with those with a score of 0 (<i>P</i> &lt; .001). The aHRs of all-cause mortality for clinical tumor stage 2, 3, and 4 compared with 1 were 1.84 (95% CI, 1.07-3.40), 1.97 (95% CI, 1.03-3.77), and 2.49 (95% CI, 1.29-4.81), respectively (<i>P</i> = .009). The aHRs for all-cause mortality by clinical nodal (cN) stages were 1.49 (95% CI, 1.13-1.99) and 1.84 (95% CI, 1.31-2.61) for cN stage 1 and cN stages 2 or 3, respectively, compared with cN stage 0 (<i>P</i> = .005); those for differentiation were 1.77 (95% CI, 1.24-2.54) and 2.31 (95% CI, 1.61-3.34) for differentiation grade 2 and differentiation grade 3, respectively, compared with differentiation grade 1 (<i>P</i> &lt; .001). <h3>Conclusions and Relevance</h3> The findings of this study suggest that for patients with strongly HR-positive and<i>ERBB2</i>–negative IDC, NACT may be considered the first choice for neoadjuvant treatment.