[Differential diagnosis model of benign and malignant breast BI-RADS category 4 nodules based on serum SP70 and conventional laboratory indicators].

Objective: To develop a nomogram model for the differential diagnosis of benign and malignant breast BI-RADS (Breast Imaging Reporting and Data System) category 4 nodules based on serum tumor specific protein 70 (SP70) and conventional laboratory indicators and validate its predictive efficacy. Methods: A case-control study design was used to retrospectively analyze the data of 429 female patients diagnosed with BI-RADS category 4 breast nodules by breast color doppler flow imaging at the First Affiliated Hospital of Nanjing Medical University from January 2021 to April 2022 with an age range of 16 to 91 years and a median age of 50 years, and the patients were divided into a training cohort (314 patients) and a validation cohort (115 patients) according to the inclusion time successively. Using postoperative pathological findings as the"gold standard", univariate and multivariate logistic regression analyses were used to identify the predictor variables used for the model. The nomogram, receiver operating characteristic (ROC) curves and calibration curves were drawn for the prediction model, and the discrimination and calibration of the model were evaluated using the consistency index (C-index) and calibration plots. Results: The postoperative pathological results showed that 286 (66.7%) were malignant nodules and 143 (33.3%) were benign nodules of 429 breast BI-RADS category 4 nodules. The serum SP70 (OR=1.227,95%CI: 1.033-1.458,P=0.020), NLR (OR=1.545,95%CI: 1.047-2.280,P=0.028), LDL-C (OR=2.215, 95%CI: 1.354-3.622, P=0.002), GLU (OR=2.050,95%CI:1.222-3.438,P=0.007), PT (OR=1.383,95%CI: 1.046-1.828,P=0.023), nodule diameter (OR=1.042, 95%CI: 1.008-1.076, P=0.015) and age (OR=1.062,95%CI: 1.011-1.116,P=0.016) were independent risk factors which could be used to distinguish benign and malignant breast BI-RADS category 4 nodules (P<0.05). The nomogram was plotted by the above seven independent variables, and the concordance index (C-index) for the training cohort and validation cohort were 0.842 (95%CI:0.786-0.898) and 0.787 (95%CI:0.687-0.886), respectively. The sensitivity and specificity of using this model to identify benign and malignant breast BI-RADS category 4 nodules in the training and validation cohort were 83.5%, 72.5% and 79.2%, 73.6%, respectively. The calibration curves showed good agreement between the predicted and actual values in the nomogram. Conclusions: This study combined serum SP70, conventional laboratory indicators and breast color doppler flow imaging to develop a nomogram model for the differential diagnosis of benign and malignant breast BI-RADS category 4 nodules. The model may have good predictive efficacy and may provide a basis for clinical treatment options, which is beneficial for guiding breast cancer screening and prevention.