Chemotherapy of mediastinal germ cell tumors.

Abstract

P RIMARY GERM cell tumors of the mediastinum are rare. A recent review of 1687 patients with primary tumors and cysts of the mediastinum noted only 19 cases-an incidence slightly greater than 1% of all tumors in that anatomic region.’ In 1973, Rubush et al. reviewed 10 series and found 39 cases of malignant teratoma in 1037 patients with mediastinal tumors, an incidence of approximately 4%.* Though some mediastinal tumors may represent metastases from an occult or “burned out” testicular primary,3 careful postmortem evaluation of 20 patients with anterior mediastinal germ cell tumors supported the view that the great majority originate in the mediastinum.4 This is also reasonable from an embryologic point of view, since the urogenital ridge extends from the sixth cervical vertebra to the third lumbar vertebra. Because of the rarity of the disease, collected series from a single institution are uncommon. In 1974, Memorial Hospital reported 30 patients with primary mediastinal germ cell tumors,’ and 17 cases were reported in 1978 from the M. D. Anderson Hospital.h All histologic subtypes described in testicular cancer were found: seminoma, teratoma, embryonal carcinoma, and choriocarcinoma. The incidence in both series were similar: pure seminoma in 10 and 5 patients, pure embryonal carcinoma in 4 and 1, mixed tumors in 16 and 10, and pure choriocarcinema in 0 and I, respectively. Review of the literature reveals wide variation in histologic terminology, but the tumors can be broadly divided into seminomatous and nonseminomatous types. This separation also applies to their prognosis and treatment. Seminoma is the most common pure subtype as well as the most treatable. Surgery alone, or surgery plus radiation therapy, are effective in mediastinal seminoma, with reported long-term survival rates greater than SO%.‘.s.7~~9 Sterchi and Cordell, in their 1975 review, found an overall 5-yr survival rate of 58% in 105 patients, only 5 of whom were known to have received chemotherapy.’ While chemotherapy without irradiation is very uncommon as the single therapeutic modality, a patient with metastatic mediastinal