Predicting the burden of axillary disease in breast cancer patients with a positive sentinel node.

Abstract

Abstract Abstract #1010 Background: Current practice is to perform a completion axillary lymph node dissection (ALND) for breast cancer (BC) patients with tumor-positive sentinel lymph nodes (SLNs). However, not all patients with positive SLNs have further ALND. Katz et al suggested a nomogram for predicting having four or more positive nodes for SLN-positive BC which could change the adjuvant radiation treatment fields. Our goal is to validate the accuracy in predicting > 4 positive axillary lymph nodes in BC patients with a positive SLN in our institution. Methods: Katz nomogram was developed from the multivariate logistic regression model using tumor histology, primary tumor size, lymphovascular space invasion, extranodal extension, the number of involved SLNs, the number of uninvolved SLNs, and the size of the largest SLN metastasis. Area Under (AUC) Receiver Operating Characteristics Curve (ROC) was calculated for the nomogram and a value more than 0.70 was accepted as providing considerable discrimination. Results: We reviewed the records of 319 patients with invasive BC and positive SLNs who underwent completion ALND at MWH of UPMC. None of these patients received neoadjuvant chemotherapy The mean age was 54.2 (30-84) years. Eighty-nine patients (27.8%) had four or more positive nodes. Histology was invasive ductal carcinoma for 86.2 % of patients. The median tumor size was 2.22 (0.5-8.0) cm. Seventy percent of patients had only one involved SLN. The median size of the largest SLN metastasis on H&E staining was 9.7 mm (range, < 0.2 to 35 mm), and 24.4% of the patients had micrometastases (2 mm). Ninety nine patients (31%) had extranodal extension. The mean predicted probability of having ≥ 4 involved axillary LNs was 31.9 % (range, 1 to 99) in patients with ≥ 4 involved axillary LNs while it was it is 9.1% (range, 0.5 to 80) in patients having < 4 axillary LN metastases (P<0.001). The AUC value was 0.809. Conclusions: The Katz nomogram developed to predict having ≥ 4 involved axillary lymph nodes in BC patients with a positive SLNs is validated in our patients. Nomograms developed at other institutions should be used with caution when counseling patients regarding the risk of additional nodal disease. This nomogram will be helpful to clinicians making adjuvant treatment recommendations in practice. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1010.