Novel factors to improve prediction of nodal positivity in patients with clinical T1/T2 breast cancers.

Abstract

Memorial Sloan Kettering Cancer Center (MSKCC) and MD Anderson Cancer Center (MDACC) have established nomograms to predict sentinel node positivity. We propose the addition of two novel variables-distance of tumor from the nipple and from the skin-can improve their performance. Ultrasounds of clinical T1/T2 tumors were reviewed. Distances of the tumor from the skin and from the nipple were measured. MSKCC and MDACC nomogram predictions and the AUC-ROC for each model were calculated. The added utility of the two variables was then examined using multiple logistic regression. Of 401 cancers studied, 79 (19.7 %) were node positive. The mean distance of tumors from the nipple in node-positive patients was 4.9 cm compared with 6.0 cm in node-negative patients (p = 0.0007). The mean distance of tumors from the skin was closer in node-positive cases (0.8 cm) versus node-negative cases (1.0 cm, p = 0.0007). The MSKCC and MDACC nomograms AUC-ROC values were 0.71 (95 % CI 0.64-0.77) and 0.74 (95 % CI 0.68-0.81). When adjusted for the MSKCC predicted probability, addition of both distance from nipple (p = 0.008) and distance from skin (p = 0.02) contributed significantly to prediction of nodal positivity and improved the AUC-ROC to 0.75 (95 % CI 0.70-0.81). Similarly, distance from nipple (p = 0.002), but not distance from skin (p = 0.09), added modestly to the MDACC nomogram performance (AUC 0.77; 95 % CI 0.71-0.83). Distance of tumor from the nipple and from the skin are important variables associated with nodal positivity. Adding these to established nomograms improves prediction of nodal positivity.