Neoadjuvant FinHer regimen in patients with HER2-positive breast cancer: a retrospective audit

The role of trastuzumab in the neoadjuvant setting has been established by multiple large randomized trials. However, there are limited data on the efficacy and survival outcomes of the FinHer regimen in the neoadjuvant setting for the treatment of HER2-positive breast cancer in the South Indian population.

This retrospective audit included patients with locally advanced HER2-positive breast cancer who received neoadjuvant chemotherapy with a short course of trastuzumab (nine weekly doses) following the FinHer protocol in a resource-limited setting. The primary endpoint of the study was pathological complete response (pCR). Secondary endpoints included disease-free survival (DFS) and overall survival (OS) at 5 years. The primary study population comprised stage III patients, while patients with oligometastatic disease were included as an exploratory cohort.

This retrospective audit included 100 patients. Of these, 76 patients had stage III disease and 24 had oligometastatic disease. The pCR rate was 30% following the neoadjuvant FinHer protocol. Estrogen receptor (ER) and progesterone receptor (PR) positivity were associated with decreased pCR rates, which were statistically significant (p = 0.002). Patients with the HER2-enriched subtype (47%) achieved higher pCR rates compared to those with the luminal B HER2-positive subtype (21.2%), with a statistically significant p-value (p = 0.008). On univariate and multivariate analyses, stage was the only significant predictor of DFS (p = 0.003) and OS (p = 0.002). Stage III disease remained independently associated with improved survival outcomes compared to oligometastatic disease [OS: hazard ratio (HR) 0.35, 95% confidence interval (CI) 0.18-0.70, p = 0.003; DFS: HR 0.40, 95% CI 0.21-0.76, p = 0.005]. Achievement of pCR was associated with a numerically lower risk of death and recurrence (OS: HR 0.56, 95% CI 0.24-1.30; DFS: HR 0.51, 95% CI 0.22-1.16).

The neoadjuvant FinHer protocol resulted in a pCR rate of 30% in locally advanced HER2-positive breast cancer. ER/PR positivity was associated with decreased pCR rates. Achievement of pCR was associated with a numerically lower risk of death and recurrence. Stage III disease remained independently associated with improved survival outcomes compared to oligometastatic disease.