Treatment of chromophobe adenomas with megavoltage irradiation

Abstract

From 1956-1972, 62 previously untreated patients with chromophobe adenomas received high-dose (average equivalent dose: 5700rads in 6 weeks) megavoltage (4-4.8 MeV) irradiation at Stanford, 33 postoperatively and 29 as the only intended treatment. Initialtreatment failure rates were 18% and 41%, respectively; however, overall control was 85% and 90%, despite 2 uncontrolled "invasive" adenomas in each group. Nine of the 12 failures in the group treated by irradiation alone had cystic tumors, and 9 of the 12 "failed" in less than 3 months. Despite a considerably greater degree of abnormal vision initially in the postoperative irradiation group, improvement of vision with treatment in that group was 83% (19% returned to normal) compared to 46% (only 8% to normal) in the irradiation alone group. Based upon an evaluation of the extent of findings at diagnosis and our results, we recommend surgical decompression followed by 5000 rads in 5 weeks for patients with any one or more of the following findings: 1)more than minimal depression of peripheral visual fields; 2) corrected visual actuity of less than 20/30 in either eye; or 3)more than 1-cm suprasellar extension of tumor. We recommend irradiation alone, as specified, for smaller adenomas accompanied by less extensive or no visual abnormalities.