Abstract
Abstract Background: The optimal timing for sentinel lymph node biopsy (SLNB) in the neoadjuvant setting is still unclear. Evidence for both, feasibility (detection rate, DR) and accuracy (false negative rate, FNR) of SLNB before and after primary systemic treatment (PST) is restricted to monocentric and/or retrospective trials. The success rates for SLNB are particularly unclear for patients who are downstaged from a cN1 to a ycN0 status. Material and Methods: The German SENTINA (SENTInel NeoAdjuvant) trial is a 4-arm prospective multicenter cohort study designed to evaluate a specific algorithm for the timing of a standardized SLNB procedure in patients, who undergo PST and to provide reliable data for the DR and FNR in different settings. Patients were categorized into four treatment arms according to the clinical axillary staging before and after chemotherapy. Patients with a cN0 status underwent SLNB prior to PST and were categorized as arm A and B: If the SLN was histologically negative no further axillary surgery was performed after PST (arm A), whereas in case of histologically positive SLN status, a second SLNB and axillary dissection (AD) was performed after PST (arm B). Patients with a cN1 status prior to PST underwent no axillary surgery prior to PST and were stratified as arm C and D: If patients converted to cN0 after PST, SLNB and AD were performed (arm C); patients presenting with cN1 status after PST underwent classical AD (arm D). Results: 1737 eligible patients from 103 institutions entered the trial. From these 662 patients were classified as arm A, 360 pts as arm B, 592 pts as arm C and 123 pts as arm D. The DR for SLNB was 1013/1022 (99.1%) before PST (arms A and B), 474/592 (80.1%) in Arm C (after PST), and 219/360 (60.8%) in arm B (after prior SLNB and PST) (p < 0.001). 226/474 pts (47.7 %) in arm C with a detected SLN after PST had a positive and 248 (52.3 %) had a negative axillary status. The SLN was false negative in 32 pts (14.2 %, 95% CI 9.9%–19.4%). From 219 patients in arm B with a detected SLN after PST 64 (29.2 %) had a positive and 155 (70.8 %) a negative axillary status. The SLN was false negative in 33 pts (51.6 %, 95% CI 38.7%–64.2%). Conclusion: In patients, who convert from a positive to a negative cN stage during PST the DR for the SLNB is significantly lower compared to patients, who undergo SLNB prior to any other treatment. The FNR is less favorable compared to primary SLNB. Prior systemic and/or surgical treatment significantly impairs the success rates of SLNB. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr S2-2.
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