Background: The Memorial Sloan-Kettering Cancer Center (MSKCC) developed a nomogram to predict the presence of sentinel lymph node (SLN) metastasis in breast cancer patients. Our study was designed to validate the clinical value of the MSKCC nomogram in Chinese early-stage breast cancer population.

Methods: Data were collected from 524 patients with successful SLN biopsy who were treated during 2005 March to 2009 October. Positive SLN metastasis was found in 154 patients. Touch imprint cytology (TIC) and serial section with H&E staining were performed routinely on each sentinel node. Univariate analysis and logistic regressions tested whether a characteristic was correlated with the SLN positivity. MSKCC nomogram was used to estimate probability of SLN involvement and compared with actual probability after grouping into deciles. A ROC curve was drawn and predictive accuracy was assessed by calculating the area under the receiver-operating characteristic (ROC) curve.

Results: It was shown that age, tumor size, histological grade and lymphovascular invasion was correlated with the probability of SLN metastasis by univariate analysis (P<0.05). By multivariate analysis, tumor size and lymphovascular invasion were identified as independent predictors of SLN metastasis. The odds ratio (OR) of the lymphovascular invasion was 9.462(95% CI 5.551-16.130)while OR of tumor size was 1.429(95% CI 1.142-1.788). The trend of actual probability in various decile groups was comparable to the predicted probability. Patients in the group with the least probability of a positive SLN predicted by the nomogram (≥10 decile) were all diagnosed with a negative SLN by serial section by H&E staining. Three patients in our collective with extremely high probability (≥90) were all diagnosed as positive SLN by pathology. The area under the ROC curve was 0.757 as compared to 0.754 in the original population. Conclusion: As far as we know, this is the first study designed to evaluated the MSKCC nomogram in Chinese early breast cancer population. The MSKCC nomogram that predicts metastasis of breast cancer in the sentinel lymph node performed good in a Chinese breast cancer population. Though the nomogram cannot be an alternative of SLN biopsy, it could provide a clinical accessory in the preoperative discussion with patients, especially in the very high or very low risk of patients. The nomogram could be used in very low risk patients to safely avoid a SLN procedure, thereby reducing postoperative morbidity, whereas the rate could be as high as 7% in the literature. While for patients with very high risk estimated by the nomogram, axillary lymph node dissection could be recommended directly. The shortcoming of the nomogram is that clinical and pathological parameters include detail histological diagnosis of the primary tumor before the final decision for surgical procedure.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-20.