Sequential Chemoradiotherapy with 24 Gy of Cranial Irradiation for Intracranial Germinoma diagnosed with MRI

Abstract

To evaluate the efficacy of 24 Gy of sequential chemoradiotherapy with cranial irradiation omitting spinal canal for intracranial germinoma diagnosed using magnetic resonance imaging (MRI). Eighteen intracranial germinoma patients who were diagnosed with MRI and biopsy were treated by sequential chemoradiotherapy between 1996 and 2005. Fifteen male and three female patients were enrolled. Median age was 14 years (range, 9-38). Fifteen patients were diagnosed as pure germinoma and three were as germinoma with sysncytiotrophoblastic giant cells. Primary tumor sites were located in pineal gland in 11 patients and neurohypophyseal in 5. Multiple lesions including ventricular dissemination were identified in 6 patients. No patient had spinal dissemination on MRI. Endocrine dysfunctions were detected in 9 patients at diagnosis. As protocol, three cycles of induction chemotherapy composed of etoposide (150 mg/m2/day on day 1, 2, 3) and platinum agent (carboplatin 600 mg/m2 on day 1 or cisplatin 20 mg/m2/day on day 1, 2, 3) were administered. The prescription of radiotherapy was 24 Gy per 12 fractions. Standard clinical target volume (CTV) was whole ventricle (WV) with surrounding 2 cm area of brain tissue. Local CTV was applied for patients treated before 1998. Spinal canal was excluded from CTV. Maintenance chemotherapy was used for 10 patients between 1998 and 2003. Follow-up MRI was done every 6 months up to 5 years, and once a yare later. All patients completed three courses of induction chemotherapy and prescribed radiotherapy. No grade 4 hematologic or grade 3 other toxicities were observed. After the completion of radiotherapy, all patients were evaluated as complete remission on MRI. Median follow-up time was 7.5 years (range, 4-13.5). Overall, disease free and recurrence free survival at 5 years were 100%, 100%, and 94%. One patient treated with local CTV developed periventricular intracranial recurrence outside of irradiated volume at 12 months and was successfully salvaged by additional sequential chemoradiotherapy. Recurrence was not occurred in other patients. Nine patients (50%) who had diagnosed endocrine disorder before treatment continued to receive hormonal substitution therapy after treatment and one patient who experienced recurrence developed hypopituitarism after salvage treatment. Endocrine disorder was not newly occurred in other patients. Secondary malignancies were not detected in any patients. Twenty-four Gy of sequential chemoradiotherapy for intracranial germinoma is safe and effective. Whole ventricle CTV might be enough for the tumor control and spinal irradiation might not be necessary for patients who had no spinal dissemination on MRI.