Evaluation of residual tissues after adjuvant therapy in germ cell tumors

Abstract

Objective: Germ cell tumors are the tumors sensitive for adjuvant therapy such as radiotherapy and chemotherapy. We evaluated the pathological findings of these heterogeneous tumors to determine the persistence of residual viable tumor cells after adjuvant therapy.

Patients and methods: Between 1988 and 2005, we treated 31 patients with germinoma or germinoma with syncytiotrophoblastic giant cells (STGC) and 15 patients with non-germinomatous malignant germ cell tumors (NGMGCTs). All 46 patients received a combination of chemo- and radiotherapy. A second-look operation was performed in 3 of 31 patients with germinomas or germinomas with STGC and 12 of 15 patients with NGMGCTs. The follow-up period was 2-139 months (median 95) in patients with germinomas or germinomas with STGC (group 1) and 10-202 months (median 65) in NGMGCT patients (group 2).

Results: Post-treatment, 3 group 1 and 12 group 2 patients manifested residual tumors. The pathological diagnosis in group 1 patients was mature teratoma, pineal cyst, and fibrous tissue with calcification; in group 2 it was yolk sac tumor (n = 1), immature teratoma (n = 3), mature teratoma (n = 4), and necrosis or fibrous tissue (n = 4). While no group 1 patients manifested tumor cells, MIB-1-positive viable tumor cells were present in resected tissues from one-third of the group 2 patients (3 immature teratomas and 1 yolk sac tumor).

Conclusion: The absence of viable tumor cells in residual tissue indicates that the combination of cisplatin-based chemo- and radiotherapy was effective in our germinoma patients. On the other hand, in patients with NGMGCTs, these cells persisted despite this combination therapy.