Predicting Micro-TESE among Heterogeneous Nonobstructive Azoospermic Patients: The Impact on Surgical Decision and ICSI

Background. Previously published predictive models for microdissection testicular sperm extraction (micro-TESE) were generally assumed patients with nonobstructive azoospermia (NOA) a homogenous population, i.e., the laboratory predictors were associated with sperm retrieval rate (SRR) in a similar way among different subpopulations. In addition, previous studies primarily regarded the success of sperm retrieval as the sole endpoint, although live birth is the ultimate goal for the couples. Objectives. The main objective is to develop and evaluate the clinical benefit of a model predicting the clinical outcome of micro-TESE in heterogeneous population with NOA. The outcome of pregnancy was taken into account via assessing the association between the predicted outcome of micro-TESE and pregnancy. Materials and Methods. A development cohort of 1,292 patients with NOA and an external validation cohort of 530 patients were included. Sperm retrieval was performed using micro-TESE. Clinical outcomes, including sperm retrieval, clinical pregnancy, and live birth, were collected. We developed a model using the machine learning method random forest and provided a web-based calculator. Results. The SRR was 38.1% (492/1,292) in the development cohort and 48.5% (257/530) in the validation cohort. The final model includes etiology, AMH, sperm retrieval surgical history, testicular volume, FSH, LH, and age as predictors (ordered by variable importance). The area under the curve of our model was 0.76 (0.74-0.79) in the development cohort and 0.75 (0.71-0.79) in the external validation cohort. The decision curve analysis showed that personalized model-based surgical decision provides additional clinical benefit. The clinical pregnancy rate (CPR) and cumulative live birth rate (CLBR) were 45.3% (405/895) and 57.6% (338/587), respectively, in the overall population. For patients of different SRR, the CPR and CLBR of whom had successful sperm retrieval were similar. Discussion and Conclusion. Our model predicting the SRR of micro-TESE was generalizable and easy to use. Predicted pregnancy outcomes like CPR and CLBR could also be derived from predicted SRR. A model-based surgical decision after personalized consultation would be beneficial to patients with NOA.