Omission of Routine Frozen Section for Clinically Node-Negative Patients Undergoing Upfront Mastectomy Avoids Unnecessary Axillary Treatment.

BACKGROUND

Randomized trials established the safety of postmastectomy radiation/regional nodal irradiation (PMRT) as an alternative to axillary lymph node dissection (ALND) for cN0 patients undergoing upfront mastectomy with one or two positive sentinel lymph nodes (+SLNs). In January 2022, the authors adopted a policy omitting routine frozen section for cT1-3N0 patients undergoing upfront mastectomy, and this study sought to examine the impact of this policy on axillary treatment.

METHODS

Consecutive patients with cT1-3N0 breast cancer who underwent upfront mastectomy from January 2022 to July 2023 were identified. For patients with three or more +SLNs and those with one or two +SLNs not meeting institutional PMRT criteria, ALND was indicated. This study evaluated ALND/PMRT rates after adoption of this policy.

RESULTS

In this study, 623 patients with cT1-3N0 breast cancer had upfront mastectomy with sentinel lymph node biopsy. Overall, 4.7% (n = 29) of the patients had completion ALND (cALND). These patients had larger tumors, and more often had lobular histology and LVI. Of 98 patients with one or two +SLNs, 86 (88%) underwent PMRT and no further surgery, and 8 (8%) had ALND due to no initial PMRT indication, of whom 2 then met PMRT criteria based on additional positive nodes, and 4 had neither. Among those with three or more +SLNs (n = 29), 21 (72%) underwent both ALND and PMRT, and 8 (28%) had PMRT alone or neither treatment. Overall, return to the operating room for ALND was indicated for 39 (6.2%) of the 623 patients with three or more +SLNs and for those who had one or two +SLNs without PMRT indication.

CONCLUSIONS

In this study, only 6% of the cN0 patients who had SLN frozen section omitted at upfront mastectomy exhibited an indication for cALND. Receipt of ALND+PMRT for the patients with involvement of one or two nodes was rare, occurring for just 2% of the patients. Axillary management was optimized by routine omission of frozen section for cT1-3N0 patients undergoing upfront mastectomy.