The Role of Biologic Tumor Markers in Testicular Cancer

Serial quantitative measurements of serum alphafetoprotein (AFP) and human chorionic gonadotropin (HCG) have been prospectively studied in 386 patients with testicular germ cell cancer during the past seven years using sensitive and specific radioimmunoassays (RIAS). When HCG and AFP was measured in patients with nonseminomatous testicular tumors (NSTT), about 90% of these patients with active tumors have elevated levels of serum HCG and/or AFP. These markers have proven valuable in reducing the clinical staging errors to 5-14% by measuring their serum levels during the pre- and post-lymphadenectomy periods. The role of these markers have been demonstrated in monitoring the therapy and determining the prognosis of patients with NSTT. Although serum AFP has not been observed in patients with seminoma, serum HCG has been observed in patients with pure seminoma. Although these markers are seen with certain other cancers, their differential diagnosis does not pose a problem. However, since most seminoma and about 10% of NSTT do not produce these markers, their value in differential diagnosis of a scrotal mass is limited. In interpretation of these markers, one should consider their biologic half-lives and their discordant behavior while the patient is under therapy. Concentrating the 24 hour urine and extracting the urinary HCG content by using a carboxy-terminal RIA enhance the potential for a more sensitive monitoring of the tumor burden and for guiding the therapy of certain patients with testicular cancer. Finally, there are a number of potential markers under investigation in our laboratory.