Maximizing the clinical usefulness of a nomogram to select patients candidate to sentinel node biopsy for cutaneous melanoma

Abstract Aims Investigators from the Memorial Sloan Kettering Cancer Centre (MSKCC) have proposed a nomogram for predicting the sentinel node (SN) status in patients with cutaneous melanoma. The negative predictive value (NPV) of this test, which might help identify low-risk patients who might be safely spared SN biopsy (SNB), has not been yet investigated. Methods We tested the discrimination (area under the curve [AUC]), the calibration (linear regression) and the NPV of MSKCC nomogram in 543 patients treated at our institution. Different cut-off values were tested to assess the NPV, the reduction of SNB performed and the overall error rate obtained with the MSKCC nomogram. Results SN was positive in 147 patients (27%). Mean predicted probability was 17.8% (95%CI: 16.8–18.8%). Nomogram discrimination was significant (area under the curve = 0.68; P