Risk factors for non-sentinel lymph node metastasis and validation study of the MSKCC nomogram in patients with breast cancer        QIU Peng-fei*, LIU Juan-juan, WANG Yong-sheng, et al. *Breast Cancer Center, Shandong Cancer Hospital, Jinan 250117, China
Corresponding author: WANG Yong-sheng, E-mail: wangysh2008@yahoo.com.cn
Abstract    Objective    To evaluate the risk factors for non-sentinel lymph node (NSLN) metastasis, and validate the value of the Memorial Sloan Kettering Cancer Center (MSKCC) nomogram for the prediction of NSLN metastasis in patients with breast cancer. Methods    A sentinel lymph node biopsy (SLNB) database containing 1227 consecutive breast cancer patients admitted between December 2001 and January 2012 in Shandong Cancer Hospital was analyzed retrospectively. The patients with positive sentinel lymph node (SLN) should be evaluated for risk factors of NSLN metastasis. MSKCC nomogram was used to estimate probability of NSLN involvement, and the predictive accuracy was assessed by calculating the trend line and the area under the receiver-operator characteristic (ROC) curve. Results    Tumor size, number of positive SLN, nuclear grade, lymphovascular invasion and multifocality correlated with NSLN metastasis (all P<0.05). Only tumor size (P=0.001), number of positive SLN (P=0.000), nuclear grade (P=0.008) and lymphovascular invasion (P=0.001) were significant independent predictors for the NSLN metastasis. The trend of actual probability in various decile groups was comparable to the predicted probability. The MSKCC nomogram presented a ROC value of 0.765. Patients with predictive values lower than 10%（51/412,12.4%） have a frequency of NSLN metastasis of 5.9%（3/51）. Conclusion    The MSKCC nomogram can provide an accurate prediction of the probability of NSLN metastasis, and give a reference basis about the axillary lymph node dissection (ALND). ALND could be avoided in patients with the predictive values lower than 10%.