Yakup Iriagac1, Eyyup Cavdar1, Kubilay Karaboyun1, Seher Yildiz Tacar2, Halil Taskaynatan3, Okan Avci1, Ahmet Yolcu4, Sibel Ozkan Gurdal5, Meltem Oznur6, Erdogan Selcuk Seber1
1Department of Medical Oncology, Tekirdag Namik Kemal University, Faculty of Medicine, 59030, Tekirdag, Turkey.
2Department of Medical Oncology, Dr. Sadi Konuk Training and Research Hospital, 59030, Istanbul, Turkey.
3Department of Medical Oncology, Ege Sehir Hastanesi, 35100, Izmir, Turkey.
4Department of Radiation Oncology, Tekirdag Namik Kemal University, Faculty of Medicine, 59030, Tekirdag, Turkey.
5Department of Surgical Oncology, Tekirdag Namik Kemal University, Faculty of Medicine, 59030, Tekirdag, Turkey.
6Department of Pathology, Tekirdag Namik Kemal University, Faculty of Medicine, 59030, Tekirdag, Turkey.
Summary
Purpose: Estrogen receptor (ER) and progesterone receptor (PgR) levels, as well as Ki-67 expression levels, are independent predictive markers in patients with hormone receptor-positive breast cancer. This study aimed to investigate the predictive significance of the formula of log (ER) * log (PgR) / Ki-67, created using these three independent predictive markers, for the pathological complete response of hormone receptor-positive/HER2-negative breast cancer patients receiving neoadjuvant chemotherapy (NACT).
Methods: This retrospective study included 126 patients with hormone receptor-positive/HER2-negative breast cancer and axillary lymph node metastasis who received NACT. The log (ER) * log (PgR) / Ki-67 value was calculated from the pre-NACT pathological evaluation results in all patients. The ideal predictive cut-off value was determined using Receiver Operating Characteristic (ROC) curve analysis. Patients were divided into two groups (cut-off ratio high and cut-off ratio low) according to this cut-off point and compared using logistic regression analysis along with clinicopathological features.
Results: The estimated ideal cut-off value distinguishing patients as pathological complete response (pCR) and pathological non-complete response (non-pCR) was 0.12 (p=0.015). According to this cut-off value, 54.8% of patients were categorized as cut-off value high and 46.2% as cut-off value low. The non-pCR rates of the groups were 91.3% and 71.9%, respectively (p=0.004). A cut-off value of 0.12 was found to be a predictive marker in distinguishing between pCR and non-pCR in both univariate and multivariate analyses.
Conclusion: The formula of log (ER) * log (PgR) / Ki-67 can serve as a simple and easy-to-use predictive marker for response to neoadjuvant therapy in patients with hormone receptor-positive/HER2-negative breast cancer receiving NACT.
Keywords: breast cancer, neoadjuvant chemotherapy, new predictive marker, hormone positive, pathological complete response.
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