Effects of multiple-drug chemotherapy (cis-diammine-dichloroplatinum, bleomycin, and vinblastine) on the maturation of retroperitoneal lymph node metastases of nonseminomatous germ cell tumors of the testis. No evidence for De Novo induction of differentiation.

Investigating the mechanisms underlying maturation of metastases of nonseminomatous germ cell tumors on administration of chemotherapy, the histologic characteristics of primary testis tumors was compared to the histologic characteristics of their retroperitoneal metastases in three historical patient groups. The metastases in Group I (20 patients) were not treated; those in Groups II (nine patients) and III (24 patients) were treated, respectively, with three cycles of dactinomycin and with four cycles of cis-diammine-dichloroplatinum, vinblastine, and bleomycin, before retroperitoneal lymph node dissection. In Group III there was a significant increase of metastases consisting of differentiated teratoma only, as compared to the metastases of Group I. However, both with and without chemotherapy, the metastases contained fewer areas of differentiated teratoma than the primary lesions. Metastases containing differentiated teratoma with and without other components, with one exception in Group III, were derived from primary tumors containing mature areas as well. Components other than mature teratoma were almost completely eradicated in Group III. These findings strongly suggest that selective destruction of components other than differentiated teratoma causes the mature histologic characteristics in the metastases upon administration of chemotherapy. The results do not support the hypothesis of induction of differentiation by the chemotherapeutic agents.