Omission of intraoperative frozen section in sentinel lymph node biopsy for early breast cancer: impact on survival outcomes

Background: The implementation of sentinel lymph node biopsy (SLNB) with permanent section (PS) analysis alone in patients who satisfied the ACOSOG Z0011 criteria did not alter the standard of care offered by the additional frozen section (FS) analysis. This study reports the patient survival outcomes of early-stage breast cancer based on SLNB techniques.

Methods: Our previous investigation examined 453 SLNB cases at King Chulalongkorn Memorial Hospital, with follow-up concluding on April 15, 2025. The retrospective cohort study included patients diagnosed with clinically node-negative primary invasive breast cancer, who underwent breast-conserving surgery. The primary endpoint was 5-year disease-free survival (DFS), while secondary outcomes encompassed the overall cumulative incidence of local, distant, and axillary recurrence, as well as overall survival (OS).

Results: Of the 453 patients undergoing SLNB, 239 underwent SLNB with PS alone, while 214 received additional FS. Kaplan-Meier analysis demonstrated a statistically significant difference in DFS between groups (log-rank P=0.008). In multivariable Cox regression analysis, with the FS group as the reference, the PS group showed a lower estimated risk of recurrence [hazard ratio (HR): 0.34; 95% confidence interval (CI): 0.15–0.79]. The 5-year DFS rates were 95.8% in the PS group and 93.5% in the FS group; however, this difference was not statistically significant when compared using crude event rates (P=0.26). OS was similar between groups (P=0.60). In the PS group, local and distant recurrence rates were 1.3% and 2.5%, respectively, with no regional recurrences observed.

Conclusions: Based on the DFS and OS outcomes from our 5-year follow-up data, SLNB with PS analysis alone in patients meeting the ACOSOG Z0011 criteria was found to be comparable to SLNB with FS analysis.