The role of tumor size, ultrasonographic findings, and serum tumor markers in predicting the likelihood of malignant testicular histology

The clinical predictive factors for malignant testicular histology remain unclear because of the low prevalence. Therefore, the aim of this study was to investigate predictors of malignant histology for testicular masses and decide more testis-sparing surgeries before surgery. This retrospective study enrolled 325 consecutive testicular mass patients who underwent radical orchiectomy (310/325) or testicular preserving surgery (15/325) from January 2001 to June 2016. The clinicopathological factors, including tumor diameter, cryptorchidism history, ultrasound findings, serum alpha-fetoprotein, and human chorionic gonadotropin (HCG) levels, were collected retrospectively for statistical analysis. A predictive nomogram was also generated to evaluate the quantitative probability. Among all patients, 247 (76.0%) were diagnosed with a malignant testicular tumor and 78 (24.0%) with benign histology. Larger tumor diameter (per cm increased, hazard ratio [HR] = 1.284, P = 0.036), lower ultrasound echo (HR = 3.191, P = 0.001), higher ultrasound blood flow (HR = 3.320, P < 0.001), and abnormal blood HCG (HR = 10.550, P < 0.001) were significant predictive factors for malignant disease in all testicular mass patients. The nomogram generated was well calibrated for all predictions of malignant probability, and the accuracy of the model nomogram measured by Harrell's C statistic (C-index) was 0.92. According to our data, the proportion of patients who underwent radical orchiectomy for benign tumors (24.0%) was much larger than generally believed (10.0%). Our results indicated that the diameter, ultrasonic echo, ultrasonic blood flow, and serum HCG levels could predict the malignancy in testicular mass patients.