Combining Endocrine Therapy with Trastuzumab Emtansine Improves Progression-Free Survival and Overall Survival in HER2-Positive, Hormone Receptor-Positive Metastatic Breast Cancer.

Background and Objectives: Patients with human epidermal growth factor receptor 2 (HER2) -positive, hormone receptor-positive (HR-positive) metastatic breast cancer (MBC) usually undergo trastuzumab emtansine (T-DM1) therapy in subsequent lines. Combining endocrine therapy (ET) with T-DM1 can improve treatment outcomes in this subtype. Therefore, this study aimed to investigate the benefits of using T-DM1 with ET in HER2-positive and HR-positive MBC. This study was the first to investigate the benefits of combining ET with T-DM1. Material and Methods: This study analyzed the medical records of patients with HER2-positive and HR-positive MBC who were treated with T-DM1 from June 2010 to December 2021. The patients were divided into groups based on whether they received concomitant ET with T-DM1. The primary endpoint was to determine the progression-free survival (PFS), while the secondary endpoints were overall survival (OS), objective response rate, and safety of the treatment. Results: Our analysis examined 88 patients, of whom 32 (36.4%) were treated with T-DM1 in combination with ET. The combination therapy showed a significant improvement in median PFS (15.4 vs. 6.4 months; p = 0.00004) and median OS (35.0 vs. 23.1 months; p = 0.026) compared to T-DM1 alone. The ORR was also higher in the combination group (65.6% vs. 29.3%; p = 0.026). Patients treated with pertuzumab priorly had reduced median PFS on T-DM1 compared to those who were not treated with pertuzumab (11.7 vs. 5.4 months, respectively; p < 0.01). T-DM1 demonstrated better median PFS in HER2 3+ patients compared to HER2 2+ patients, with an amplification ratio of >2.0 (10.8 vs 5.8 months, respectively; p = 0.049). The safety profiles were consistent with previous T-DM1 studies. Conclusions: The combination of T-DM1 with ET can significantly improve PFS and OS in patients with HER2-positive and HR-positive MBC. Our study suggests that prior pertuzumab treatment plus trastuzumab treatment might decrease T-DM1 efficacy.

The role of laboratory indices on treatment response and survival in breast cancer receiving neoadjuvant chemotherapy.

Neoadjuvant chemotherapy (NACT) is the standard treatment for locally advanced, high-risk breast cancer. Pathological complete response (pCR) improves survival. Peripheral blood-derived indices reflecting systemic inflammation and nutritional status have long been used as predictive and prognostic markers in solid malignancies. This retrospective study investigates whether eight commonly used indices in patients receiving NACT affect pCR and survival. This study includes 624 locally advanced breast cancer patients who received NACT. The biomarker indices were calculated from peripheral blood samples taken two weeks before starting chemotherapy. The indices' optimal cut-off values were determined using ROC Curve analysis. During a median follow-up period of 42 months, recurrence was detected in 146 patients, and 75 patients died. pCR was observed in 166 patients (26.6%). In univariate analysis, NLR, PLR, SII, PNI, HALP, and HRR were statistically significantly associated (p = 0.00; p = 0.03; p = 0.03; p = 0.02; p = 0.00; p = 0.02 respectively), but in multivariate analysis, only NLR was significantly predictive for pCR(p = 0.04). In multivariate analysis, the HGB/RDW score significantly predicted DFS(p = 0.04). The PNI score was identified as a marker predicting survival for both OS and PFS (p = 0.01, p = 0.01, respectively). In conclusion, peripheral blood-derived indices have prognostic and predictive values on pCR and survival. However, further studies are needed to validate our findings.

Neoadjuvant Chemotherapy and Pathologic Complete Response in HR+/HER2- Breast Cancer: Impact of Tumor Ki67 and ER Status.

INTRODUCTION: Neoadjuvant chemotherapy (NAC) is extensively employed in breast cancer (BC), primarily for aggressive subtypes like triple-negative and human epidermal growth factor receptor 2 (HER2) positive BC, and in estrogen receptor-positive (ER+)/ HER2- BC with high-risk features. In ER+/HER2- breast cancer, pathological complet rates are much lower (<10%), while axillary dissection rates are higher. This study focuses on hormone receptor positive (HR+)/HER2- BC patients undergoing NAC, examining its impact on pathological complete response (pCR) rates, with specific attention to tumor Ki67 and ER status. METHODS: Retrospective data analysis from Kartal Dr. Lütfi Kirdar City Hospital included HR+/HER2- BC patients who received NAC. Clinicopathological factors, NAC response, and surgical outcomes were assessed. Statistical analyses evaluated the association between Ki67, ER status, and pCR. RESULTS: Of 203 patients, 11.8% achieved pCR. Ki67 (p<0.001) and ER percentage (p<0.001) significantly correlated with pCR. Higher Ki67 was associated with increased pCR likelihood (HR: 1.03, 95% CI: 1.01-1.05). A Ki67-pCR probability curve revealed a cutoff of 23.5%. ER%-pCR analysis showed decreasing pCR rates with higher ER percentages. Multivariate analysis confirmed Ki67 (p=0.003, HR: 1.02) and ER percentage (p=0.019, HR: 0.97) as independent predictors of pCR probability. CONCLUSION: Consideration of Ki67 and ER percentage aids in NAC decisions for HR+/HER2- BC, identifying patients with high NAC response rates, facilitating axillary preservation, and potentially avoiding axillary dissection. The pCR rates in patients with Ki67 ≤ 24 are particularly low, especially in patients with a high ER percentage. In these cases, upfront surgery and adjuvant treatment should be considered instead of NAC.