Gamma Knife Surgery for Postoperative Residual Nonfunctioning Pituitary Adenomas

Lee, Dong Jun; Lee, Sun-Il; Park, Jin Sam; Jeon, Sang Ho; Pyo, Se Yeong; Jeong, Yeong Gyun; Kim, Moo Seong; Jung, Yong Tae

Review article

Journal of the Korean Society of Stereotactic and Functional Neurosurgery 2006;2(1):37-43.
Published online June 30, 2006.

Gamma Knife Surgery for Postoperative Residual Nonfunctioning Pituitary Adenomas

Dong Jun Lee, Sun-Il Lee, Jin Sam Park, Sang Ho Jeon, Se Yeong Pyo, Yeong Gyun Jeong, Moo Seong Kim, Yong Tae Jung

Department of Neurosurgery, Inje University Busan Paik Hospital, Busan, Korea

Abstract

Objective
The authors evaluated the efficacy and safety of Gamma knife treatment in patients with nonfunctioning pituitary adenoma who had postoperative residual mass after surgical debulking of the tumor in order to relieve mass effect in adjacent structures and to confirm pathological diagnosis. Materials and Methods: In this retrospective study, the authors evaluated 41 patients who underwent Gamma knife treatment for residual nonfunctioning pituitary adenoma since 1996. Nineteen were men and twenty-two were women, ranging in age from 14 to 64 years The median follow up period after GK was 44 months (range 5-93 months). The mean residual tumor volume was 4.9cm3 (range 0.8-10.9cm3). The mean prescription dose was 15.3Gy and the mean prescription isodose curve was 50.93%. The size of residual tumor was measured by magnetic resonance imaging 6 months-interval after GK and follow up study involved hormonal evaluation and neuro-ophthalmological examination.
Results
The tumor volume was unchanged in 26 patients (63%) and decreased in 15 patients (37%). Two of 41 patients had a recurrence 31 and 50 months after GK. The recurrence free interval was 100% at 2 yeasrs, 96% at 3 years, 87% at 5 years. No additional visual impairment and no hormonal deterioration was developed in any patients.
Conclusion
Gamma knife treatment was effective in controlling the patients of postoperative residual nonfunctioning pituitary adenoma and had few risk of radiation side effect compared with fractionated radiotherapy. We suggest the initial surgical debulking followed by Gamma knife treatment for nonfunction pituitary adenoma is strongly recommended to avoid surgical mobidity, and to increase the efficacy and to decrease radiation toxicity of Gamma knife treatment.

Key Words: Gamma knife radiosurgery, Nonfunctioning pituitary adenoma.