The search for biomarkers of metastatic seminoma.

Abstract

We screened 90 potential parameters as biomarkers of metastatic seminoma to facilitate detection and eliminate unnecessary therapeutic or diagnostic efforts. A total of 527 men with pure seminoma (diagnosed 2000 to 2011) were followed during therapy. More than 90 demographic/anamnestic (eg age, height, weight) histopathological parameters (testicular/tumor size, testicular intraepithelial neoplasia) and levels of tumor markers (eg α-fetoprotein, β-human chorionic gonadotropin, lactate dehydrogenase) in peripheral blood and testicular vein were collected for analysis via logistic regression. Previously described risk factors (tumors larger than 4 cm, infiltration of rete testis) were assessed separately. Established parameters such as tumor length (p = 0.0003), involvement of lymphatic (p <0.0001) or vascular channels (p = 0.0009), extent of primary tumor (p <0.0001) and infiltration of the tunica albuginea (p = 0.02) as well as new biomarkers such as absence of testicular intraepithelial neoplasia in tumor bearing testis (p = 0.03), testicular volume (p = 0.04) and tumor volume (p = 0.02) showed a significant association with metastatic disease. This association was also true of lactate dehydrogenase, human chorionic gonadotropin and α-fetoprotein (p <0.0001 at maximum). However, the discriminatory capacity of these biomarkers (concordance or ROC area) did not exceed 65% when examined alone or in combination, and higher values (up to 80%) were detected for enzyme levels. A subset of metastatic seminoma (2% to 27%) was detectable with high accuracy (positive predictive value 92% to 100%) based on enzyme measurements (p <0.0006). New biomarkers of metastatic seminoma were identified and previously described risk factors were validated. Further prospective studies of these novel parameters are warranted to verify our findings and to explore a potential use for detecting occult metastases.