Stereotactic radiosurgery for recurrent/residual nonfunctioning pituitary adenoma: a single-arm systematic review and meta-analysis

Background: Nonfunctioning pituitary adenomas (NFPAs) are a significant subtype of pituitary tumors, accounting for 30% of all pituitary tumors and 10-20% of intracranial tumors. The primary treatment for NFPAs is resection, but complete resection is often challenging due to the tumor's proximity to critical structures, leading to frequent recurrences. Stereotactic radiosurgery (SRS) has emerged as a viable treatment option for recurrent or residual NFPAs, but its long-term efficacy and safety profile require further investigation.

Methods: This systematic review followed PRISMA guidelines and included studies published up to February 2024. We searched MEDLINE, Embase, and Cochrane databases for studies evaluating SRS for recurrent/residual NFPAs. Inclusion criteria focused on studies reporting outcomes and complications of SRS, while exclusion criteria omitted case reports, case series, and non-English studies. Data extracted included demographic details, dosimetry parameters, and follow-up durations. The risk of bias was assessed using the ROBINS-I tool, and statistical analyses were performed using single-arm meta-analyses.

Results: A total of 24 studies involving 3,781 patients were included. The mean follow-up duration was 60 months. Tumor control was achieved in approximately 92.3% of patients. The risk of developing hypopituitarism post-SRS was 13.62%, while the risk for panhypopituitarism was 2.55%. New visual field deficits occurred in 3.94% of patients. Cranial nerve deficits were rare, with event rates below 1% for CN III, CN V, and CN VI.

Conclusion: SRS is effective in managing recurrent or residual NFPAs, achieving high tumor control rates. However, the risk of hypopituitarism remains a significant concern, necessitating regular endocrinological monitoring. While generally safe, the potential for new visual field deficits and other cranial nerve deficits must be considered. SRS remains a valuable treatment option, but clinicians should be aware of its potential complications.