Abstract P1-01-08: A Nomogram for predicting two or less axillary lymph node involvement for breast cancer

Abstract

Abstract BACKGROUND: Completion axillary lymph node dissection (ALND) is currently the standard of care in the event of a positive sentinel lymph node biopsy (SLNB). However, result from Z0011 indicate that women with a one or two involved axillary nodes and clinical T1-T2 tumors undergoing lumpectomy with radiation therapy followed by systemic therapy do not benefit from completion of ALND in terms of survival. As a result, the use of intraoperative frozen section during SLNB will be declined. OBJECTIVE: To define possible predictors of having two or less involved axillary node using preoperative image study to provide information for surgeons making decision about sparing intraoperative frozen section analysis of sentinel lymph node. METHODS: We reviewed the records of 1214 patients with clinical T1-T2 and clinical node negative invasive breast cancer. None of these patients were in situ cancer on initial gun biopsy nor received neoadjuvant chemotherapy. Factors associated with having three or more involved axillary nodes were evaluated by univariate and multivariate logistic regression analysis. RESULTS: Among 1214 patients, 203 patients (16.7%) had three or more positive nodes. On a multivariate analysis, having three or more positive nodes was associated with primary tumor size by breast US, axillary LN grade according to cortical thickness by US and presence of axillary LN enlargement on chest CT. The area under ROC curve corresponding to the multivariate logistic regression model applied to dataset of 1214 patients was 0.827 (95% CI: 0.793–0.860). When applied to a validation dataset of 378 patients, it was 0.899 (95% CI: 0.841–0.957). A nomogram to predict the probability of having two or less axillary nodes involvement based on patients' age and preoperative image findings was developed from the multivariate logistic regression model. CONCLUSION: Patients with a low probability of having three or more positive nodes can be identified from preoperative image finding. The nomogram developed will be helpful to surgeons making decision about sparing intraoperative frozen section analysis of sentinel lymph. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-01-08.