Abstract PO5-17-05: Recommendations of a panel of experts from the Brazilian Society of Mastology on breast and axilla clipping: when, how and for whom?
Authors: Couto Henrique , Hassan Augusto , Steinmacher Dalton , Pessoa Eduardo , Millen Eduardo , Zerwes Felipe , Cavalcante Francisco Pimentel , Tosello Giuliano , Badan Gustavo , Francisco José , Soares Leonardo , Budel Lucas , Chala Luciano , Fernandes Raquel , Freitas-Junior Ruffo , Oliveira Vilmar , Budel Vinicius , Mattar Andre 
Published: May 2024

Abstract
Background: The precise location of the tumor site is essential for obtaining free margins and success of surgical treatment, reducing the rates of reoperation and local recurrences. Neoadjuvant chemotherapy (NAC) is a challenge for preoperative tumor localization, due to the different patterns of locoregional response, limitations related to imaging methods, and the possibility of a pathological complete response (pCR). In addition, there are several divergent approaches regarding preoperative axillary evaluation, lymph node marking methods and approaches when facing cN1. Thus, the knowledge and attitudes of the affiliated members of the Brazilian Society of Mastology (SBM) regarding breast and axilla marking were evaluated and a consensus regarding management and treatment was reached.
Methods: This is an online survey conducted between June and December 2022. All 1.742 active mastologists affiliated to SBM were anonymously invited to participate in the study. The online form contained 28 objective questions, of which 22 were formulated on a Likert scale. These questions addressed several relevant aspects related to breast and axilla marking in the neoadjuvant setting. Responses that reached 70% agreement were considered consensual. Statistical analysis was performed using the SPSS program. Post hoc analysis was performed when appropriate and, in all analyses, the significance level of p &lt; 0.05 was adopted.
Results: A total of 468 mastologists answered the questionnaire (26.8%), with a predominance of professionals aged between 40-49 years (32.1%), male (50.4%), and residents of state capitals (63.9%). Most professionals were board-certified (84,8%), 87.7% for more than five years. The indication of tumor marking in the breast prior to NAC was consensual (96.4%) and the metal clip was the preferred method (69.7%). If available, the US-visible clip is preferred (86.5%). With respect to the marking of the breast and axilla prior to NAC, 93.3% of the mastologists considered relevant issues related to the techniques and materials. There was no consensus regarding the indication of pre-NAC histologically positive lymph node marking (49.8% disagree and 42.8% agree), however there was consensus that the clinical and imaging evaluation is insufficient for staging the axilla as N1 (71.6 %). The contraindication of breast and node marking in T4b tumors (71.2%) was consensual. There was consensus on the indication of sentinel lymph node biopsy (SLNB) for initially cN1 (92.3%) or cN2 (72.7%) tumors that became cN0 after NAC, with 67.5% opting for dual staining with technetium and patent blue. There was also consensus on the indication of axillary lymphadenectomy (89%) after NAC when double marking with technetium and patent blue for SLNB is not available. In addition, 41.0% of mastologists perform axillary lymphadenectomy when less than three lymph nodes are found in the SLNB. Among the 28 questions, consensus was reached on only 11 (39.3%); with some consensus variations according to age group, sex, geographic location of residence, place of professional activity (public or private), and professional experience.
Conclusion: The indication of pre-NAC breast marking is consensual among Brazilian mastologists, although axillary nodal marking is not. There is a great divergence of attitudes among Brazilian surgeons in relation to the many issues related to pre-NAC breast and axilla marking, indicating the need to establish continuing education programs on the subject.
Citation Format: Henrique Couto, Augusto Hassan, Dalton Steinmacher, Eduardo Pessoa, Eduardo Millen, Felipe Zerwes, Francisco Pimentel Cavalcante, Giuliano Tosello, Gustavo Badan, José Francisco, Leonardo Soares, Lucas Budel, Luciano Chala, Raquel Fernandes, Ruffo Freitas-Junior, Vilmar Oliveira, Vinicius Budel, Andre Mattar. Recommendations of a panel of experts from the Brazilian Society of Mastology on breast and axilla clipping: when, how and for whom? [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-17-05.