Multisession CyberKnife radiosurgery for post-surgical residual and recurrent pituitary adenoma: preliminary result from one center.

OBJECTIVE

To evaluate the efficacy of CyberKnife (Accuray, Inc., Sunnyvale, CA) stereotactic radiosurgery (SRS) for patients with pituitary adenoma.

METHODS

We conducted a retrospective review of all patients treated by image-guided radiosurgery at our institution between August 2007 and June 2009. Twentytwo patients with pituitary adenoma were identified. The median follow-up period from date of treatment was 30.8 + 7.7months. The median patient age was 56 years. The mean tumor volume was 4.1 + 2.8 mL (range, 0.8-16.0 mL), and the prescribed dose was 25 Gy (5 Gy x 5).

RESULTS

Tumors were treated with a mean coverage of 95.1 ± 1.3%(range 90.2-99.1%), a mean conformality index of 1.4 ± 0.4 (range, 1.2-1.8), and a mean treatment isodose line of 76.4 ± 3.0%(range70-83%). The primary endpoints were radiographic and endocrinological tumor control. The local radiographic control rate in this series was 100% (22/22). Radiographic evidence of tumor necrosis developed in 3 patients (13.7%).

CONCLUSION

CyberKnife multisession radiosurgery of 25 Gy (5 Gy x 5) provided excellent local control with acceptable adverse effect in patients with pituitary adenoma post-transsphenoidal resection. This preliminary study provides data that supports the belief that the optic nerve and chiasm tolerate the above dosing regimens in perichiasmatic pituitary adenomas, and this dosing regimen may achieve satisfactory radiographic and endocrinological tumor control for post-transsphenoidal resection.