Stereotactic Radiosurgery for Non-Functioning Pituitary Adenomas Recurrence With Low Dose 12 Gy

Introduction: The existing literature presents varying opinions on the appropriate dosage of stereotactic radiosurgery (SRS) for the recurrence of nonfunctional pituitary adenomas (NPAr). While it is theorized that administering higher doses may reduce the likelihood of recurrence, there is a growing concern that such doses could compromise neurological function by damaging nearby structures. Therefore, our study aims to evaluate the effectiveness of low-dose SRS at 12 Gy in treating NPAr recurrence, in comparison to higher radiation doses.

Methods: An institutional review board-approved retrospective study was conducted for patients who underwent SRS for NPAr from 2006 to 2022. Collected information included demographics, treatment parameters, preoperative and postoperative neurologic and endocrinologic function, and postoperative hormone management. Patients treated with 12 Gy were compared to all other patients with a dosage range of 1/13 to 28/50.4.

Results: A total of 63 patients were included in the study, 23 of which were treated with 12 Gy and 40 treated with different doses of radiation. The average follow up was 21 and 34 months, respectively. No significant differences were found in gender, age, tumor volume, preoperative hormone replacement, endocrine function, diabetes insipidus, and cranial nerve (CN) deficit between groups (p = 0.117, p = 0.531, p = 0.482, p = 0.793, p = 0.439, p = 0.494, and p = 0.535, respectively). Additionally, no significant differences were found in postoperative hormone replacement, hormone replacement in 1 year, diabetes insipidus, CN deficit, CN deficit in 1 year, and recurrence post radiation (p = 0.603, p = 0.399, p = 0.652, p = 0.535, p = 0.214, and p = 0.701, respectively).

Conclusion : SRS treatment of NPAr using a low dose of 12 Gy is as effective as higher radiation doses while minimizing the risk of functional neurological deficits and showed noninferiority to compared modalities.