Analysis of repeat stereotactic radiosurgery for progressive primary and metastatic CNS tumors

Abstract 

: To identify and evaluate the pretreatment and patient factors that would predict for complications after repeat radiosurgery.

: The data from 26 patients who underwent reirradiation with Gamma Knife surgery after a previous procedure in the same or subjacent location were available for evaluation. The range of follow-up was 1–45 months (mean 10). The mean minimal and maximal initial dose and volume for all 26 patients was 16.2 Gy (range 12–22), 31.0 Gy (range 22.2–40.0), and 12.4 cm³ (range 1.20–70.84), respectively. The mean marginal and maximal repeated radiosurgery dose and volume for all 26 patients was 14.9 Gy (range 12–22.5), 29.7 Gy (range 18.0–45.0) and 12.8 cm³ (range 1.10–39.20), respectively.

: Tumor control was significantly better statistically (p = 0.0129) for benign tumors (6 of 6, 100% actuarial rate at 4 years) compared with malignant tumors (7 of 20, 35% actuarial rate at 3 years, 3 of 4 metastatic tumors and 2 of 10 primary malignant gliomas). The retreatment volume for radiosurgery correlated significantly with the probability of neurologic decline (any cause) (p = 0.0181).

: Repeat radiosurgery can be performed for recurrent tumors with minimal central nervous system toxicity, especially for benign tumors, with reasonable tumor control.

Keywords:  Reirradiation, Radiosurgery, CNS tumors, Gamma Knife