miR-371a-3p Predicting Viable Tumor in Patients Undergoing Retroperitoneal Lymph Node Dissection for Metastatic Testicular Cancer: The SWENOTECA-MIR Study.

Purpose: The SWENOTECA-MIR prospective multicenter study aims to assess the clinical value of miR-371a-3p as a novel marker in metastatic germ cell tumor patients undergoing retroperitoneal lymph node dissection (RPLND), to predict the presence of viable residual tumor.

Materials And Methods: A total of 114 patients (86 nonseminomas, 28 seminomas) who underwent surgery for presumed metastatic disease pre chemotherapy (primary RPLND) and post chemotherapy RPLND were included. The expression of miR-371a-3p was evaluated using reverse transcription-digital droplet polymerase chain reaction before and after RPLND. Pre- and postoperative miR-371a-3p levels were statistically compared, and optimism-corrected performance calculations compared with conventional serum tumor markers. Associations were evaluated by logistic regression. Patients who underwent primary RPLND were categorized into seminoma and nonseminoma groups.

Results: Among the seminoma patients (n = 24) undergoing primary RPLND, all had normal conventional markers. Six patients received adjuvant treatment before surgery. miR-371a-3p exhibited a sensitivity of 74%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 21% for viable tumor. The levels of miR-371a-3p significantly decreased after surgery. In the nonseminoma group (n = 18) treated with primary RPLND, 22% had elevated conventional markers and 3 had received prior adjuvant treatment. miR-371a-3p showed a sensitivity of 34%, specificity of 88%, positive predictive value of 67%, and negative predictive value of 62% for the primary nonseminoma patients. No association was observed between stage or prior adjuvant treatment and the outcome of the miR test. In the postchemotherapy group (n = 72), the miR-371a-3p sensitivity was 9%, reducing to 0 when excluding patients with seminoma (n = 4). Teratomas and benign histology were essentially negative.

Conclusions: Our study highlights miR-371a-3p as a fairly sensitive and highly specific marker for prechemotherapy seminomas, outperforming conventional markers. However, in prechemotherapy nonseminomas as well as in postchemotherapy patients, we observed low sensitivity and no significant differences in miR-371a-3p levels before and after surgery, suggesting limited utility for miR-371a-3p in this context.