Nomogram for predicting preoperative axillary lymph node status in male breast carcinoma: SEER population-based study

Background: Sentinel lymph node biopsy (SLNB) has been recommended as a replacement for axillary lymph node dissection (ALND) in male breast carcinoma (MBC) with clinical axillary lymph node-negative (ALN-negative) as in the case of female. However, the morbidity after SLNB may also have short-term or long-term complications. To avoid unnecessary surgery, building a model which is able to assess the risk of lymph node metastasis is vitally significant. Methods: A retrospective review of the clinical and pathology data were carried out for patients diagnosed with MBC between 2010 and 2018 from the Surveillance, Epidemiology, and End Results (SEER) database. The cohort was divided into training and validation cohorts. A logistic regression model was used to construct the nomogram in the training cohort and then verified in the validation cohort. The receiver operating characteristic (ROC) curve, C-index, and calibration were used to evaluate the predictive ability of the nomogram. Results: Overall, 2,610 patients diagnosed with MBC were included in the study, of which 1,740 were in the training cohort and 870 were in the validation cohort. Logistic regression analysis indicated age at diagnosis, tumor location, tumor stage, pathological type, and histologic grade, were significantly related to axillary lymph node metastasis (ALNM). The area under the curve (AUC) of the nomogram was 0.846 (95% CI: 0.825-0.867) and C-index was 0.848 (95% CI: 0.807-0.889), demonstrating a notable prediction performance. The calibration curve for the nomogram was plotted and the slope was close to 1. The prognostic value of the nomogram was further validated in the validation cohort, with an AUC of 0.848 (95% CI: 0.819-0.877). Conclusions: A nomogram to predict ALNM was successfully established, especially for those who were of advanced age at diagnosis, had small tumor size, displayed low malignancy, and showed clinical ALNnegative, to avoid unnecessary axillary operation. The quality of life for patients is enhanced without conceding the overall survival rate.