Gamma knife surgery of colorectal brain metastases: a high prescription dose of 25 Gy may improve growth control.

OBJECTIVE: There are few reports on the effect of gamma knife surgery (GKS) for brain metastases from colorectal cancer. The purpose of this study was to identify prognostic factors for local control, complications, and survival in our series of patients treated with GKS. METHODS: Eighty patients (36 males, 44 females) with 140 metastases who received GKS between 1996 and 2008 were retrospectively reviewed. The mean tumor volume was 6.13 (0.01-35.5) cm(3); the prescription dose was 21.1 (10-25.1) Gy and the maximum dose 42.7 (17.2-66.7) Gy; and the tumor cover was 95.0% (72%-100%). RESULTS: Growth control was achieved in 93 of 121 tumors (76.9%) and 42 of 68 (61.8%) patients, while treatment failure was seen in 28 of 121 tumors (23.1%). Local control was better if a high prescription dose of 25 Gy was used, 88.4% vs. 71.4% (P = 0.017), or if tumor volume was <5 cm(3) (86.4%), compared with 69.9% for 5-20 cm(3) and 51.9% for >20 cm(3) (P = 0.002). The hazard ratio for local failure with lower prescription doses was 2.8 (P = 0.026) in the unadjusted, and 8.5 (P = 0.055) in the adjusted multivariate analysis (tumor volumes >5 cm(3)). The median survival was 6 months (range 0-75) after GKS. Age <70 years (P < 0.001) and high RPA class (P = 0.032) were associated with longer survival. Fifteen patients (22.1%) had persistent edema on follow-up MRI, possibly because of radiation damage to the tumor. Radiation-induced edema was asymptomatic in 93.8%. We found neither a decrease in the incidence of new metastases nor improved survival when whole-brain radiation therapy was given prior to GKS. CONCLUSIONS: GKS provides reasonable local tumor control. Local control rate is highest if the margin dose is 25 Gy and the tumor volume <5 cm(3). Radiation edema was common but rarely symptomatic. Survival is longest for young, well-functioning patients.

γ knife surgery versus reoperation for recurrent glioblastoma multiforme.

BACKGROUND: The optimal management of patients with recurrent glioblastoma multiforme (GBM) is a subject of controversy. These patients may be candidates for both reoperation and/or gamma knife surgery (GKS). Few studies have addressed the role of GKS for relapsing gliomas, and the results have not been compared with reoperation. To validate the efficacy and safety of GKS, we compared the survival and complication rates of GKS and reoperation for recurrent GBMs. METHODS: This study retrospectively reviewed 77 consecutive patients with histopathologically confirmed GBMs retreated for recurrent GBM between 1996 and 2007. Thirty-two patients underwent GKS, 26 reoperation and 19 both procedures. RESULTS: The median time from the second intervention to tumor progression was longer after GKS than after resection, P = 0.009. Median survival after retreatment was 12 months for the 51 patients receiving GKS compared with 6 months for reoperation only (P = 0.001, hazard ratio [HR] 2.4), and 19 months versus 16 months from the time of primary diagnosis (P = 0.021, HR 1.8). A multivariate analysis adjusted for possible confounding factors (tumor volume, recursive partitioning analysis class, neurological deficits, time to recurrence, adjuvant therapy, and tumor location) showed significantly longer survival for patients treated with GKS, both from retreatment (P = 0.013, HR 4.1) and from primary diagnosis (P = 0.002, HR 5.8). The adjusted results were still significant after separate analysis according to tumor volume <5 mL, 5 to 20 mL, and >20 mL. The complications rate was 9.8% after GKS and 25.2% after reoperation. CONCLUSIONS: GKS may be an alternative to open surgery for small GBMs at the time of recurrences, with a significantly lower complication rate and a possible survival benefit compared with reoperation.

Gamma knife surgery in brain melanomas: absence of extracranial metastases and tumor volume strongest indicators of prolonged survival.

OBJECTIVE: To review a series of patients who underwent Gamma Knife surgery (GKS) to identify prognostic factors for local growth control and survival. METHODS: During the period 1996-2006, 77 patients (42 men and 35 women) with a total of 143 metastases underwent GKS. A solitary lesion was present in 40 patients (51.9%). RESULTS: Growth control was achieved in 114 of 128 (89.1%) tumors and 59 of 70 (84.3%) patients. The median survival was 7 months (range 0-73 months) after GKS and 67 months (range 4-327 months) from the time of diagnosis. Patients with absence of extracranial disease lived longer than patients with more widespread disease-median 16 months (range 3-52 months) versus 6 months (range 0-73 months; P = 0.014). A total tumor volume of less than 5 cc was associated with longer survival (P = 0.041). Survival was significantly longer in recursive partitioning analysis (RPA) class 1 (22 months) than RPA class 2 (7 months) and RPA class 3 (3 months; P = 0.008). Even in cases of treatment failure with tumor growth or appearance of new metastases, GKS slowed down the cerebral disease with no significant reduction in the duration of survival. CONCLUSIONS: GKS for melanoma brain metastasis provides a high rate of local tumor control. Survival is longest for well-functioning patients with absence of extracranial metastases or with an intracerebral total tumor volume less than 5 cc.