Value of postoperative stereotactic radiosurgery and conventional radiotherapy for incompletely resected typical neurocytomas

BACKGROUND. Two groups of central neurocytomas have been identified: typical and atypical neurocytomas. The more benign typical neurocytomas have a better prognosis. Complete resection of typical neurocytomas results in significantly better outcome than incomplete resection. The current study investigated whether the outcome after incomplete resection can be improved by postoperative stereotactic radiosurgery (SRS) or by conventional radiotherapy. METHODS. The data of all neurocytoma patients reported since 1997, when the first neurocytoma patient treated with SRS was described, were reviewed. Patients who underwent complete resection or those with atypical neurocytoma were excluded from the analysis. Three different therapies were compared for overall survival (OS) and local control (LC): incomplete resection alone (ITR), ITR followed by conventional radiotherapy (ITR+cRT), and ITR followed by stereo tactic radiosurgery (ITR+SRS). RESULTS. Data were complete in 121 patients (59 ITR, 41 ITR+cRT, and 21 ITR+SRS). The 5-year-LC after ITR was 51%. LC was significantly better after ITR+cRT (87%, P = 0.001) and after ITR+SRS (100%, P = 0.004). The difference between ITR+cRT and ITR+SRS was not significant (P = 0.45). The 5-year-OS was 93% after ITR, 100% after ITR+cRT, and 100% after ITR+SRS. The differences between the various groups were not significant. The P-values were 0.13 for ITR versus ITR+cRT, 0.29 for ITR versus ITR+SRS, and 1.0 for ITR+cRT versus ITR+SRS. CONCLUSlONS. After ITR of typical neurocytomas, LC is significantly improved by both conventional radiotherapy and SRS. The results of both radiation treatments were similar. SRS is a reasonable alternative to conventional radiotherapy in selected patients.