Identification of Factors Predicting False-Negative Results in Sentinel Lymph Node Biopsy in Patients Undergoing Surgery for Breast Cancer: A Single-Center Retrospective Study.

Background In breast cancer surgery, sentinel lymph node biopsy (SLNB) is routinely utilized for axillary assessment. Frozen section examination of the sentinel lymph node (SLN) is used to guide the decision for axillary dissection. Adjuvant treatment is also planned based on the final pathological examination of the axilla and the mastectomy/breast-conserving surgery specimen. In rare cases, even when the frozen section examination of the SLN is negative, micrometastases and macrometastases can still be detected in the final pathologic examination. In our study, we aimed to analyze the characteristics of patients who underwent surgery for breast cancer and were found to have false-negative results in SLNB. We aimed to identify potential predictive markers for false-negative results in SLNB. Methodology A total of 206 patients with breast cancer who underwent surgery in our department between January 2018 and September 2023 were evaluated retrospectively. In total, 12 patients with false-negative SLNB results and 12 patients with true-negative SLNB results were reviewed. Demographic information of the patients, type of breast malignancy, hormone receptor status, the number of lymph nodes dissected in SLN sampling, and whether the patients received neoadjuvant treatment were recorded. Results The results of 12 cases with false-negative results in SLNB were compared with 12 cases with true-negative results. The ages of the cases ranged from 33 to 80 years, and the mean age was 57.00 ± 12.55 years. The mean age was 59.92 ± 9.72 years in the group with false-negative SLNB results and 54.08 ± 14.71 in the group with true-negative SLNB results. No significant difference was found between the groups (p > 0.05). No statistically significant difference was determined in tumor size, stage, estrogen receptor, progesterone receptor (PR), C-ERB, HER-2, and E-cadherin between the groups (p > 0.05). It is noteworthy that PR was detected at a higher rate in the false-negative SLNB group. In cases with false-negative results in SLNB, the absence of treatment response in the postoperative pathological examination was found to be statistically significantly higher. On the other hand, complete response and partial response rates were significantly higher in the SLNB true-negative group (p = 0.011 and p < 0.05). However, because response rates cannot be assessed preoperatively, they cannot be considered a predictive factor. Mean Ki-67 (%) of the cases with true-negative SLNB results was statistically significantly higher than the false-negative group (p = 0.017 and p < 0.05). Conclusions SLNB is routinely performed in breast cancer for the evaluation of the axilla. Examining a single blue-stained lymph node may be sufficient for SLN assessment. In the preoperative period, there is no imaging method, pathological finding, or data that can definitively predict the probability of a positive SLN. Even when the patient has received neoadjuvant therapy, unnecessary lymph node dissection should be avoided during SLN sampling.