Gamma Knife Surgery for Residual or Recurrent Craniopharyngioma After Surgical Resection: A Multi-institutional Retrospective Study in Japan

Abstract

Objective The optimal treatment for a craniopharyngioma has been controversial. Complete resection is ideal, but it has been difficult to obtain total resection in many cases because of intimate proximity to critical structures such as the optic pathway, hypothalamus, and pituitary gland. A growing number of studies have demonstrated the utility of radiosurgery in controlling residual or recurrent craniopharyngioma. However, most of them are small series. The aim of this multi-institutional study was to clarify the efficacy and safety of Gamma Knife (Elekta, Stockholm, Sweden) surgery for patients with a craniopharyngioma. Methods This was a multi-institutional retrospective study by 16 medical centers of the Japan Leksell Gamma Knife Society. Data on patients with craniopharyngiomas treated with Gamma Knife Surgery (GKS) between 1991 and 2013 were obtained from individual institutional review board-approved databases at each center. A total of 242 patients with craniopharyngioma were included in this study. The mean age of the patients was 41 (range, 3 to 86) years. The median follow-up time was 61.4 months (range, 3 to 180 months). The mean radiosurgery target volume was 3.1 ml (range, 0.03-22.3 ml), and the mean marginal dose was 11.4 Gy (range, 8-20.4 Gy). Results Two-hundred twenty patients were alive at the time of the last follow-up visit. The three-, five-, and 10-year overall survival rates after GKS were 95.4%, 92.5%, and 82.0%, respectively. The three-, five-, and 10-year progression-free survival rates after GKS were 73.1%, 62.2%, and 42.6% respectively. The rate of radiation-induced complications was 6.2%. Conclusion GKS is effective for controlling the tumor growth of craniopharyngiomas with an acceptable complication rate.

Keywords: craniopharyngioma; gamma knife; radiosurgery.

Figure 1. Overall survival

Kaplan-Meier curve showing the OS of 242 patients with a craniopharyngioma. The actual three-, five-, and 10-year OS rates after the first GKS was 95.4%, 62.5%, and 82.0%, respectively. OS = Overall Survival, GKS = Gamma Knife Surgery

Figure 2. Overall survival depending on the type of the first operation

Kaplan-Meier OS curves showed no statistically significant difference in relation to the types of the first operation (Log-rank, P = 0.1629). P < 0.05 statistically significant, OS = Overall Survival, GKS = Gamma Knife Surgery

Figure 3. Progression-free survival

Kaplan-Meier curve showing the PFS of 242 patients with a craniopharyngioma. The actual three-, five-, and 10-year PFS rates after the first GKS was 73.1%, 62.2%, and 42.6%, respectively. PFS = Progression-Free Survival, GKS = Gamma Knife Surgery

Figure 4. Progression-free survival depending on the types of the first operation

Kaplan-Meier PFS curves showed no statistically significant difference in relation to the types of the first operation (Log-rank, P = 0.2626). P < 0.05 statistically significant, PFS = Progression-Free Survival, GKS = Gamma Knife Surgery

Figure 5. Illustrative case

A 66-year-old female. Coronal T1-weighted magnetic resonance imaging (MRI) with gadolinium (Gd) enhancement depicting a recurrent craniopharyngioma during GKS (A). The recurrent tumor was treated with a margin dose of 11 Gy. Follow-up MRI with Gd enhancement performed 40 months after GKS showing tumor regression (B). GKS = Gamma Knife Surgery; MRI = Magnetic Resonance Imaging