Abstract P5-09-13: LumiSystem-guided lumpectomy enables informed customization of radiation therapy in select patients with breast cancer

Le résumé fourni par la source

Abstract Background: For most patients who undergo lumpectomy, adjuvant radiation therapy is standard of care (SOC) following surgery. There is an increasing emphasis on de-escalation or omission of radiotherapy, for which achieving the most complete tumor resection is particularly critical to minimize the risk of recurrence. When used as an adjunct to standard lumpectomy, the LumiSystem has been shown to remove residual cancer missed by the initial surgery and reduce the rate of positive margins. We evaluated whether eligibility for de-scalation or omission of radiotherapy changed based on the LumiSystem intervention. Methods: In this prospective trial, we assessed margin status with and without LumiSystem-guided surgery for patients with stage 0-3 breast cancer. After surgeons completed their standard lumpectomy procedure, patients were randomly assigned 10:1 to receive further LumiSystem-guided surgery for positive signal or not. For patients randomized to the LumiSystem intervention, eligibility for de-escalation or omission of radiotherapy, both after standard lumpectomy and after LumiSystem intervention, were retrospectively determined based on eligibility criteria from RTOG 9804, CALGB 9343, PRIME II, LUMINA, IDEA, BR007/DEBRA and the 2024 ASTRO Partial Breast Irradiation Guidelines. According to these criteria, the population of interest included only patients >49 yr. with various tumor characteristics intended to identify lower risk patients. Results: 357 patients received LumiSystem-guided surgery, and a retrospective chart review was performed by two independent breast specialized radiation oncologists for the 166/357 (46.5%) patients that had additional LumiSystem-guided excisions taken after standard lumpectomy. 133/166 (80.1%) patients reviewed had negative margins after standard lumpectomy and 77/166 (46.4%) patients (age: median - 66 yr., range - 51-82 yr.) were eligible for omission of radiotherapy after standard lumpectomy based on the aforementioned eligibility criteria. 9/77 (11.7%) patients (age: median 51 yr., range 51-77 yr.) who were eligible for omission of radiotherapy following standard lumpectomy had residual tumor removed in subsequent LumiSystem-guided excisions. These residual tumor deposits included grade 3 histology and ranged from 1-11mm in size. 33/166 (19.9%) patients had a positive margin after standard lumpectomy, and 9/33 (27.3%) of these patients were converted to negative margins intraoperatively by LumiSystem-guided wider negative margins. 3/33 (9.1%) of these patients (age: median - 57 yr., range 54-73 yr.) with positive margins after standard lumpectomy had a change in eligibility for omission of radiotherapy based on LumiSystem-guided wider negative margins, and 2/33 (6.1%) patients also became eligible for smaller volumes of accelerated partial breast irradiation. Discussion: LumiSystem-guided surgery altered radiation therapy recommendations in a subset of patients. Among patients eligible for omission of adjuvant radiotherapy based on SOC negative margins, identification of fluorescence in the lumpectomy cavity resulted in removal of unsuspected residual tumor. These findings support the notion that those patients who historically have recurred without radiotherapy may have had residual disease left behind after standard lumpectomy. Using LumiSystem as an adjunct to standard lumpectomy may lead to the potential of the reducing targeted volume of radiation therapy and the option to omit radiation in additional patients. Long-term follow-up data is needed to determine if the risk of local recurrence is lower in patients undergoing LumiSystem-guided surgery, particularly in those who are candidates for radiation omission. Citation Format: Simona Shaitelman, Roberto Diaz, Brian Schlossberg, Manna Chang, Kate Smith, Jorge Ferrer, Kelly K. Hunt, David Carr, Peter Blumencranz, E. Shelley Hwang, Irene Wapnir, Barbara L. Smith. LumiSystem-guided lumpectomy enables informed customization of radiation therapy in select patients with breast cancer [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P5-09-13.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.