SUO 2020: Real-World Application of Pre-Orchiectomy miR-371A-3P Test in Testicular Germ Cell Tumor Management

(UroToday.com) Current serum tumor markers for testicular germ cell tumor are limited by low sensitivity, with several drawbacks, including, (ii) low expression in seminoma, embryonal carcinoma, and teratoma and (ii) ~50% sensitivity. Taken together, pre-orchiectomy serum tumor markers are not ideal to diagnose malignant disease. However, there is growing evidence supporting the use of circulating miR-371a-3p as a superior marker for malignant (viable) germ cell tumor management. At the 2020 Society of Urologic Oncology (SUO) virtual meeting, Dr. Rohit Badia and colleagues presented results of their evaluation of the real-world application of serum miR-371a-3p levels in detecting viable germ cell tumors among patients undergoing partial or radical orchiectomy.

For this study, serum samples were collected from 69 consecutive patients prior to orchiectomy. Performance characteristics of serum miR-371a-3p were compared with conventional serum tumor markers (AFP/ꞵ-hCG/LDH) between viable germ cell tumor patients and those without viable germ cell tumor on orchiectomy pathology. Relative miR-371a-3p levels were correlated with clinical course. Kruskal-Wallis test and linear and ordinal regression models were used for analysis.

This study population included 58 patients with viable germ cell tumors and 11 healthy controls. In the viable germ cell tumor group, 48% of the population was white, as well as an impressive 48% were Hispanic. 50% of the tumors were nonseminomatous germ cell tumors (NSGCT) and 50% were seminoma. For detecting viable germ cell tumor, combined conventional serum tumor markers had a specificity of 100%, sensitivity of 58%, and area under the curve (AUC) of 0.79. The miR-371a-3p test showed a specificity of 100%, sensitivity of 93%, and AUC of 0.978.

Median relative expression of miR-371a-3p in viable germ cell tumor patients was >6,800-fold higher than in patients lacking viable germ cell tumors. MiR-371a-3p levels correlated with composite stage (p=0.006), and, among clinical stage I patients, was independently associated with embryonal carcinoma percentage (p=0.0012) and tumor diameter (p<0.0001). Six patients received orchiectomy after chemotherapy and were correctly predicted to have presence or absence of viable germ cell tumor by the miR-371a-3p test. A Limitation of the current study was the inability to discriminate between viable disease versus teratoma.√
Dr. Badia concluded his presentation with the following take-home points:

If validated, the miR-371a-3p test can be used in conjunction with conventional serum tumor markers to aid clinical decision-making
A positive miR-371a-3p test in patients after preoperative chemotherapy or with solitary testes could potentially guide subsequent orchiectomy or observation

Presented by: Rohit R. Badia, University of Texas Southwestern Medical Center, Dallas, TX

Co-Authors: Dreaux Abe, Daniel Wong, Nirmish Singla, Anna Savelyeva, Nathan Chertack, Liwei Jia, Payal Kapur, Matthew J. Murray, James F. Amatruda, John T. Lafin, Aditya Bagrodia

Written by: Zachary Klaassen, MD, MSc – Assistant Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia Twitter: @zklaassen_md at the 2020 Society of Urologic Oncology Annual Meeting – December 2-5, 2020 – Washington, DC

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