Receptor discordances after neoadjuvant chemotherapy and their effects on survival

To determine estrogen, progesterone and HER2 receptors' discordances after neoadjuvant chemotherapy in patients with locally advanced breast cancer and their effects on survival.

Data of 186 patients who were admitted to our oncology departments between 2000 and 2014, were retrospectively evaluated. Patients'status of hormone and HER2 receptors were assessed before and after neoadjuvant chemotherapy. Univariate and multivariate Cox regression analyses, Kaplan-Meier and Log-rank tests were used, as appropriate. P<0.05 was considered as statistically significant.

Median follow-up was 35 months. Of the patients, 20% had stage II disease and 80% stage III disease. Also, 74% showed hormone receptor positivity and 42% had HER2 overexpression. Hormone receptor discordance was detected in 63 (34%), HER2 discordance was detected in 33 (18%), and any receptor discordance was detected in 74 (40%) patients. There was a statistically significant difference regarding 5-year disease-free survival (DFS) between groups with loss of HER2 overexpression and without loss of HER2 overexpression (p=0.003). Five-year DFS was 60% with loss of any positive receptor status after chemotherapy and 72% with no change in any receptor status (p=0.023). In multivariate analysis, clinical stage (HR: 3.3, 95% CI: 1.18-9.3, p=0.022), changing HER2 status from positive to negative (HR: 2.6, 95% CI: 1.3-5.1, p=0.005), and triple-negative receptor status (HR: 2.64, 95% CI: 1.3-5.6, p=0.001) had significant impact on DFS.

In patients with locally advanced breast cancer, loss of HER2 overexpression is an independent risk factor for DFS. Further studies are needed to determine the impact of receptor discordances.