Novel factor to improve prediction of sentinel node positivity in patients with clinical T1/T2 breast cancer.
49 Background: Predicting nodal positivity can guide surgical planning in breast cancer. Memorial Sloan-Kettering Cancer Center (MSKCC) and MD Anderson Cancer Center (MDACC) have established nomograms to predict sentinel node positivity. We propose that addition of distance of tumor from the nipple (DFN) can improve their performance. Methods: With IRB approval clinical T1/T2 tumors with pre-biopsy ultrasound were reviewed. MSKCC and MDACC nomogram predictions and the AUC-ROC were calculated. The addition of DFN was examined using multiple logistic regression and comparison of AUC-ROC values. Results: 401 breast cancers with clinical T1 (85%) or T2 (15%) tumors in 395 patients were included; of which 79/401 (19.7%) were node positive. Tumors were significantly closer to the nipple in those with positive nodes. 17/33 (51.5%) tumors within 2 cm of the nipple were node-positive versus 62/368 (16.8%) tumors > 2 cm from the nipple (p<0.0001). The MSKCC and MDACC nomograms each demonstrated good discrimination between node positive and negative patients with AUC-ROC values of 0.71 (95% CI: 0.64-0.77) and 0.74 (95% CI: 0.68-0.81), respectively. When added to the MSKCC nomogram, DFN ≤2 cm contributed significantly (OR 4.78, p=0.0001) to prediction of node positivity and improved the AUC-ROC to 0.73 (95% CI: 0.67-0.80). Similarly, DFN ≤2 cm was significant (OR 4.73, p=0.0002) when added to the MDACC nomogram and improved the AUC to 0.76 (95% CI: 0.70-0.82). Within nomogram probability categories, the proportion with positive nodes was consistently higher with DFN ≤2 cm. Conclusions: Tumor distance from nipple is associated with nodal positivity. When added to nomograms it improves prediction of node positivity. DFN should be considered when considering likelihood of nodal positivity for treatment planning. [Table: see text]