AUTHOR=Choi Joon Young , Woen Doyoun , Jang Sung Yoon , Lee Hyunjun , Shin Dong Seung , Kwak Youngji , Lee Hyunwoo , Chae Byung Joo , Yu Jonghan , Lee Jeong Eon , Kim Seok Won , Nam Seok Jin , Ryu Jai Min 

TITLE=Risk factors of breast cancer recurrence in pathologic complete response achieved by patients following neoadjuvant chemotherapy: a single-center retrospective study

JOURNAL=Frontiers in Oncology

VOLUME=Volume 13 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2023.1230310

DOI=10.3389/fonc.2023.1230310

ISSN=2234-943X

ABSTRACT=Pathologic complete response (pCR) of breast cancer after neoadjuvant chemotherapy (NAC) is highly related to molecular subtypes. Patients who achieved tumor pCR after NAC have a better prognosis. However, despite of better prognosis, pCR patients have a potential for recurrence.There is little evidence of risk factors of recurrence in patients with pCR. We aim to analyze factors associated with tumor recurrence in patients who achieved pCR. We retrospectively reviewed the data of patients diagnosed with breast cancer who achieved pCR after receiving NAC between January 2009 and December 2018 in Samsung Medical Center. pCR was defined as no residual invasive cancer in breast and axillary nodes even if there is residual ductal carcinoma in situ. Breast cancers are classified into 4 subtypes based on hormone receptors (HR) and human epithelial growth factor receptor 2 (HER2) status. Patients who had bilateral breast cancer, ipsilateral supraclavicular or internal mammary lymph node metastasis, inflammatory breast cancer, distant metastasis, unknown subtype, and histologically unique case were excluded from the study. In total 483 patients were included in this study except for patients who corresponded to the exclusion criteria. The median follow-up duration was 59.0 months (range, 0.5-153.3 months). Breast cancer recurred in 4.1% of patients (20 of 483). There was a significant difference in clinical T (P = 0.004) and clinical N (P = 0.034) stage in the Kaplan-Meier curve for disease-free survival. Molecular subtypes (P = 0.573), Ki67 (P = 1.000), and breast surgery type (P = 0.574) were not associated with tumor recurrence in patients who achieved pCR. Univariable Cox regression revealed statistical significance in cT (P = 0.049) and cN stage (P = 0.010), while multivariable Cox regression demonstrated non-significance in cT (P = 0.320) and cN stage (P = 0.073).Results showed that cT, cN stage, and molecular subtypes were not statistically significant predictors of recurrence in pCR-achieving patients. Although, pCR may be more important than clinical staging and molecular subtype in early breast cancer. In addition, escalated treatments for patients with HER2 + or triple-negative tumors would be considered with a strict patient selection strategy to prevent over-treatment.