Purpose: The finding of an unexplainable persistent low level of serum human chorionic gonadotropin in the management of testicular cancer sometimes misleads physicians. To avoid unnecessary treatment we suggest a new classification and algorithm for testicular germ cell tumors to discriminate real human chorionic gonadotropin from false-positive results.
Materials and methods: A total of 24 patients who seemed to have no cancer with an increased but low level of serum human chorionic gonadotropin were evaluated. They included 17 patients with testicular germ cell tumors and 7 with no evidence of germ cell tumor. In these cases parallel serum and urine human chorionic gonadotropin were measured with the same assay and serum human chorionic gonadotropin was measured with a different assay. False-positive cases were identified by critical criteria according to the classification of gestational trophoblastic disease.
Results: Of 17 cases of testicular germ cell tumor 12 were classified as false-positive and 5 were classified as true-positive. All of the other 7 cases with no evidence of cancer were classified as phantom cases. Of the 7 patients with phantom human chorionic gonadotropin who had a history of germ cell tumor unnecessary treatments had been performed in 3. After the discrimination was implemented no unnecessary treatments or intensive examinations were performed.
Conclusions: Appropriate management is possible based on a good understanding of the causes of low human chorionic gonadotropin. Our algorithm for classifying low human chorionic gonadotropin may help avoid unnecessary treatment in these patients.