Evaluating Tumor Size to Ki67 Proliferation Index Ratio for Optimizing Surgical Axillary Treatment Decisions in Breast Cancer Patients

Despite advancements in breast cancer surgery, the decision-making process for axillary treatment remains complex, necessitating new predictors like the tumor size to Ki67 proliferation index ratio. Intraoperative examination of the sentinel lymph node is performed to reduce the risk of a secondary surgery. Several studies have demonstrated that even in the presence of moderate nodal involvement, local disease control can be achieved by omitting axillary lymph node dissection (ALND). The aim of our retrospective study is to compare patients subjected to sentinel lymph node biopsy (SNLB) with or without intraoperative evaluation. This study included patients with breast cancer who underwent breast-conserving surgery and SNLB. Of the 551 patients, 333 (60.4%) underwent an SNLB intraoperative evaluation (SLNB-IE), while 218 (39.6%) underwent sentinel lymph node dissection diagnostic evaluation (SLNB-DE). Our analysis revealed that the tumor size to Ki67 ratio is an independent predictive factor for axillary tumor burden, suggesting its utility in surgical decision-making. A secondary ALND was performed in 2 (0.6%) vs. 7 (2.8%), p = 0.032, and in 1 (0.4%) vs. 4 (2.1%), p = 0.171, excluding patients with T ≥ 2. Surgical time was significantly shorter (p > 0.001) in the SLNB-DE group. According to a multivariate analysis, lesion dimension (OR 1.678; 95%CI 1.019–2.145; WALD:7.588; p = 0.006) and the ratio of lesion dimension to the Ki67 proliferation index (OR 0.08; 95%CI 0.011–0.141; WALD:11.004 p = 0.001) were both predictive factors for a higher axillary tumor burden. A value of 0.425, which is the ratio of tumor dimension to the Ki67 proliferation index, was identified as a predictor of tumor burden in the axilla (sensitivity, 78%; specificity, 87.5%). Intraoperative evaluation of SNLB may be omitted but could be considered in potential candidates for cyclin inhibitor and cN0 therapy with a higher ratio of tumor dimension to the Ki67 proliferation index in order to avoid secondary surgery.