Memorial Sloan-Kettering Cancer Center Nomogram to predict the risk of non-sentinel lymph node metastasis in Japanese breast cancer patients

Axillary lymph node dissection (ALND) remains the standard procedure for breast cancer patients with sentinel lymph node (SLN) metastasis; however, additional nodal metastasis is detected in completion ALND in only about 50% of these patients. To identify the risk of non-SLN metastasis, the Memorial Sloan-Kettering Cancer Center (MSKCC) developed a nomogram. Many validation studies have been performed to evaluate the accuracy of the nomogram in Western populations, but not in Asians. We conducted this study to establish the accuracy of the nomogram in a Japanese population. The accuracy of the MSKCC nomogram for predicting non-SLN status was tested in 116 consecutive SLN-positive patients in our hospital. We then compared the findings of the source MSKCC study with those of our study. A receiver operating characteristics (ROC) curve was plotted, and the area under the curve (AUC) was calculated to assess the discriminative power. Despite the differences between our patients and the source population in many respects, the area under the ROC curve was 0.73, which was comparable to that obtained in the study on the source population. The MSKCC nomogram provides a fairly accurate predicted probability for the likelihood of non-SLN metastases. Accordingly, it served as a useful tool for our Japanese patients with SLN metastases.