Radiotherapy to primary CNS germinoma: how large an irradiated volume is justified for tumor control?

Between 1990 and 1999, there were 30 primary central nervous system (CNS) germinoma patients who received radiotherapy (RT) as treatment. Of these, 23 are male and 7 are female patients, with a median age of 16 years. The treatment field of RT included whole neuraxis in 10, whole brain in 8 and local tumor site in 12 patients; the median dose delivered to the whole neuraxis being 3060 cGy, with 3060 cGy to the whole brain and 5040 cGy to the tumor site. Chemotherapy was prescribed in 9 patients. The median time on follow-up for survivors is 73 months. There were 7, out of a total of 30 patients, who suffered treatment failure. Five of twelve patients (41.6%) who received partial brain RT failed in the brain, with no difference in the rate between patients with or without chemotherapy, and only 2 of 18 patients (11.1%) who received whole brain or whole neuraxis RT failed in the brain (p = 0.053). None of 5 spinal seeding patients failed in the spine and only one failed in the brain after whole neuraxis RT, one patient without whole neuraxis RT (5%) failed in the spine. In summary, partial brain RT will have higher probability of intracranial relapse, and sparing the spinal RT will not result in more spinal failure, whole brain RT would be sufficient for tumor control on primary CNS germinoma.