Nomogram-guided sentinel node strategy in early breast cancer: Evaluation and comparison with current de-escalation approaches

We externally validated the Memorial Sloan Kettering Cancer Centre (MSKCC) sentinel node nomogram and compared its performance as an SLNB omission strategy with that of the SOUND and INSEMA trial strategies and the ASCO 2021 guideline. We retrospectively analysed 1,080 women with clinically and sonographically node-negative EBC treated at a tertiary Australian centre between 2012 and 2020. Predicted nodal risk was generated using the MSKCC calculator. Discrimination and calibration were assessed, and clinical utility was evaluated using false-negative rate (FNR) and negative predictive value (NPV). A nomogram-guided strategy was simulated by applying an MSKCC probability cut-off to identify patients eligible for SLNB omission. Trial and guideline criteria were applied for direct comparison. Macrometastatic nodal disease was present in 187 patients (17.3%). The MSKCC nomogram showed good discrimination (AUC 0.77, 95% CI 0.73–0.80) and reasonable calibration. At a 23% risk threshold, 308 patients (29%) were eligible for SLNB omission, with an FNR of 9.6% and the highest NPV (94.2%) among all strategies evaluated. The SOUND strategy spared 493 patients (46%), with an FNR of 29.4% and an NPV of 88.8%, while the INSEMA strategy spared 723 patients (67%), with an FNR of 53.5% and an NPV of 86.2%. The ASCO 2021 guideline was the most conservative, sparing 162 patients (15%), with an FNR of 6.9% and an NPV of 92.0%. A nomogram-guided approach may offer a flexible, risk-adapted alternative for SLNB omission, though prospective validation and long-term follow-up are required.