Abstract
Background/aim: Following the National Comprehensive Cancer Network guidelines, radiotherapy is administered after breast-conserving surgery (BCS) in patients with more than four positive lymph nodes. Four positive lymph nodes are typically considered an indicator to assess disease spread and patient prognosis. However, the subjective counting of positive axillary lymph nodes underscores the need for biomarkers to improve diagnostic precision and reduce the risk of unnecessary treatments. Loss of E-cadherin expression is associated with cancer metastasis, but its potential as a predictive marker for cancer treatment remains uncertain. This study aimed to investigate the validity of E-cadherin as a reference for adjuvant radiotherapy in breast cancer patients with positive lymph nodes post-mastectomy. Materials and methods: Immunohistochemistry was performed on 60 clinical tissue specimens to assess these implications. Results: Although no significant result was found in a single E-cadherin subgroup (low, medium, and high subgroups according to the X-tile algorithm), the proposed multivariate model, including the E-cadherin category, breast cancer subtype, and tumor size, yielded satisfactory recurrence risk estimation results for patients undergoing BCS. Patients with a low E-cadherin category, triple-negative breast cancers, and tumor size over 5 cm could have an increased risk of recurrence. Conclusion: Our study proposed a multivariate model that serves as a candidate prognostic factor for recurrence-free survival in patients undergoing BCS and radiotherapy. Utilizing this model for patient stratification in high-risk diseases and as a standard for assessing postoperative intensified therapy can potentially improve patient outcomes.