Clinical application of the ACOSOG Z0011 trial results allows clinically node-negative breast cancer patients who meet criteria to avoid axillary dissection even when 1-2 sentinel lymph nodes (SLNs) are positive for metastatic disease. Intraoperative frozen section (iFS) analyses of SLNs were thought to reduce re-operation rates despite variable reported sensitivity and possibility of a false negative result. This study evaluated the rate of re-operations prevented by SLN iFS in a tertiary care hospital in Bangkok, Thailand, over a 6-year time-frame. Patients and Methods:From April 2016 to April 2022, 1284 sentinel lymph node biopsy (SLNB) procedures were performed. Of these, 214 cases were breast-conserving surgery in accordance with the ACOSOG criteria with concomitant usage of iFS. Clinicopathological features of these cases were collected and analyzed. Re-operation rates prevented by the additional intervention were reported. Results: Only five additional operations were prevented with the usage of 214 iFS. The discordance rate between frozen and permanent sections in terms of presence of metastatic disease and number of total lymph nodes was around 15%. Tumor staging, node staging, Nottingham histologic grading and lymphovascular invasion are significant predictors of SLN metastasis. Conclusion: iFS results in a very low prevention rate for follow-up ALND in patients with preoperative clinically negative axillary nodes and is associated with a non-negligible discordance rate with permanent sections. Our study suggests iFS may be avoided in most cases of early-stage clinically and radiographically node-negative breast cancer patients. Doing so may reduce surgical costs and total operative time without a significant impact on the overall quality of treatment and standard of care.

Background In 2021, there is an increased global trend for sending sentinel lymph node biopsy (SLNB) specimens for permanent section (PS) without intraoperative frozen sections (FS). This pilot study conducted in Thailand determines the re-operation rate for SLNB without FS. Method We retrospectively reviewed 239 SLNB cases without FS at King Chulalongkorn Memorial Hospital from April 2016 to April 2021. The patients were diagnosed with primary invasive breast cancer with clinically negative nodes. The clinical nodal status was assessed from physical examination. The re-operation rate was determined by the number of positive SLNs; where 3 more nodal metastases were subjected to a second surgical procedure. Result Between April 2016 and April 2021, 239 patients who had undergone SLNB in accordance with ACOSOG Z0011 criteria with PS alone was enrolled. A total of 975 SLNs were removed from these 239 patients, with an average of 4.15 nodes per patient. Out of 239 patients, 21 (8.8%) and 6 (2.5%) had metastatic disease in 1 and 2 nodes, respectively. The remaining 212 (88.7%) patients had no nodal metastasis. None of the patients were subjected to a second surgical procedure. Conclusion We conclude that the implementation of SLNB with PS analysis alone in patients who satisfy the ACOSOG Z0011 criteria, with a re-operation rate of 0%, does not have outcomes that would be altered by the standard of care additional FS analysis. With ommision of FS analysis, operation cost, operative time and anesthetic side effects are projected to decrease.

Background: In 2021, increased implementation of the usage of permanent section (PS) without intraoperative frozen section (FS) for sentinel lymph node biopsy (SLNB) were evident worldwide. This pilot study conducted in Thailand will determine the re-operation rate in SLNB without FS technique. Method: we retrospectively reviewed 239 cases of SLNB without FS in King Chulalongkorn Memorial Hospital from April 2016 to April 2021. These patients were diagnosed with primary invasive breast cancer with clinical node negative. The clinical nodal status was assessed from physical examination. The re-operation rate was evaluated by the number of positive SLNs; equal or more than 3 nodal metastases were subjected to second surgical procedure. Result: Between April 2016 and April 2021, there are 239 patient who had undergone SLNB in accordance with ACOSOG Z0011 criteria with the use of PS alone. A total of 975 SLNs were removed from these 239 patients, with an average of 4.15 nodes per patient. Out of 239 patients, 21 (8.8%) and 6 (2.5%) had metastatic disease in 1 and 2 nodes, respectively. The remaining 212 (88.7%) patients had no nodal metastasis. None of the patients were subjected to a second surgical procedure.Conclusion: With a re-operation rate of 0%, we concluded that the implementation of SLNB with PS analysis alone in patients who satisfied the ACOSOG Z0011 criteria do not altered the standard of care offered by additional FS analysis. With cessation of intraoperative procedure, operation cost, operation time and anesthetic side effect are projected to decrease.

Background and Aims: The trend of sending sentinel lymph node biopsy (SLNB) specimens for permanent section (PS) without intraoperative frozen sections (iFS) is increasing globally. This pilot study conducted in Thailand aimed to evaluate the role of intraoperative frozen section (iFS) in early-stage breast cancer patients who underwent mastectomy with SLNB. Methods: A 5-year retrospective study of 1773 patients from December 2017 through 2022 was conducted in a tertiary care center in Thailand. The inclusion criteria were early-stage breast cancer patients with either radiologically negative nodes, or radiographically borderline nodes found to be negative on FNA in line with the AMAROS criteriawho underwent mastectomy and SLNB. Re-operations were indicated when 3 or more nodal metastases were detected on the pathological analysis. The re-operation rate prevented by iFS and the re-operation rate needed for those with PS alone were reported. Results: Among 265 patients, 202 patients underwent concomitant iFS while the remaining 63 patients underwent PS alone. Six patients (3.0%) from the iFS group and 1 patient (1.6%) from the PS group were found with more than 2 nodal metastases. Despite using intraoperative frozen sections, only one patient from each group required reoperation. There was no significant difference in the number of patients requiring reoperation between the iFS group and the PS group. Conclusions: Our study provides strong evidence to all surgeons in Thailand and low-to-middle income countries (LMIC) that in early breast cancer patients undergoing mastectomy, SLNB with PS analysis alone may not lower the standard of care compared to using additional iFS analysis. Adopting this practice may lead to decreased operation costs, operative time, and anesthetic side effects.