Abstract P2-01-11: Prospective evaluation of the reliability of the combined use of two models to predict non-sentinel lymph node status in breast cancer patients with metastatic sentinel lymph nodes: The MSKCC nomogram and the Tenon score – PHRC-NOTEGS study

Background: Several mathematical models have been developed to predict non-SN status in patients with breast cancer with SN metastasis. The Memorial Sloan-Kettering Cancer Center nomogram and Tenon score outperform other methods in academic studies but their exportability at multiple geographic locations and practice settings has never been reported. The purpose of this study was to prospectively evaluate the combined use of the MSKCC nomogram (Memorial Sloan-Kettering Cancer Center) and Tenon score to select, in patients with metastatic sentinel lymph node (SN), those at low risk of metastatic non-SN in whom additional axillary lymph node dissection (ALND) could be avoided. Material and methods: From January 2011 to July 2012, data on 3157 patients with breast cancer from 65 institutions (university affiliated, general, regional hospital, nonprofit private hospital and private practice) were prospectively recorded (NCT01509963). Selection criteria were patients aged over 18 years old with untreated invasive T1-2 breast cancer with an indication of SN procedure. The primary outcome measure was the false negative rate in patients with both a ≤10% probability of metastatic non-SN with the MSKCC nomogram and a Tenon score ≤3.5 (i.e. low risk): proportion of patients with metastatic non-SN at additional ALND. The hypothesis was a 5%±5% rate in this group of patients. Other patients were considered at high risk. Because of the results of the Z011 and IBCSG 23-01 trials, additional ALND was not mandatory.in case of metastatic SN. Results: Among the 2936 patients, at least one SN was metastatic (isolated tumor cells, micro- or macrometastasis) in 696 patients (23.7%). Among them, 178 did not have completion ALND. Among patients with completion ALND (n=518, 74.4%), 67 (13%), 437 (84%) and 14 (3%) patients were at low, high and undetermined combined risk while 47.5% were at low risk in patients without completion ALND (p Conclusion: In this controlled prospective trial, metastatic SN patients with both a ≤ 10% probability of metastatic non-SN with the MSKCC nomogram and a Tenon score ≤ 3.5 had completion axillary dissection in 47% of cases: in these patients, the false negative rate was statistically over 5% and did not reach the primary endpoint. Further evaluation is warranted to determine the outcome of patients with and without axillary dissection. Citation Format: Roman Rouzier, Catherine Uzan, Alexandra Rousseau, Eugenie Guillot, Sonia Zilberman, Charles Meyer, Pablo Estevez, Pierre-Francois Dupre, David Kere, Virginie Doridot, Gauthier D9halluin, Xavier Fritel, Nicolas Pouget, Chafika Mazouni, Tabassome Simon, Charles Coutant. Prospective evaluation of the reliability of the combined use of two models to predict non-sentinel lymph node status in breast cancer patients with metastatic sentinel lymph nodes: The MSKCC nomogram and the Tenon score – PHRC-NOTEGS study [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-01-11.