Visual Symptoms Outcomes in Cavernous Sinus Radiosurgery and a Systematic Review

Abstract

Introduction The complex anatomy of the cavernous sinus confers a true challenge when it comes to safe tumor resection. Due to its non-invasive nature, stereotactic radiosurgery (SRS) is expected to have lower mortality and morbidity rates than microsurgery. The purpose of this study was to evaluate clinical results regarding visual symptoms after SRS for benign tumors invading the cavernous sinus. We also conducted a systematic literature review to provide a robust analysis regarding visual outcomes. Methods The study included 58 patients (43 women and 15 men; mean age: 52 years) with benign tumors invading the cavernous sinus (27 pituitary adenomas and 31 meningiomas) who underwent SRS with different platforms between August 2011 and December 2021. Of these, 26 patients underwent surgery before SRS, and the remaining 32 had SRS as first-line therapy. We identified symptoms involving cranial nerves (CN) II, III, IV, and VI in 38 patients at the time of SRS. We conducted a systematic review to identify all original studies assessing visual outcomes. We searched PubMed, the Latin American and Caribbean Health Sciences Literature index, and Google Scholar using the Medical Subject Heading search terms "radiosurgery" and "cavernous sinus" for valid studies published until January 31, 2022. Results Regarding pituitary adenomas, median tumor volume was 2.05 cc, 3.12 cc, and 2.39 cc for Gamma Knife (GK), CyberKnife (CK), and tomotherapy (Tomo), respectively. Median doses were 14 Gy for GK, 17 Gy for CK, and 15 Gy for Tomo. For meningiomas, median tumor volume was 10.2 cc, 2.62 cc, and 16.3 cc for GK, CK, and Tomo, respectively. The median dose was 14 Gy for GK, 14 Gy for CK, and 14.5 Gy for Tomo. The overall tumor control rate was 100% with a median follow-up of 33 months (range: 6-128 months). A reduction of >30% in total tumor size per the Response Evaluation Criteria in Solid Tumors (RECIST) classification was documented in seven patients (RECIST II; 12.1%), 51 patients (87.9%) had stable disease (RECIST III), and no increase in tumor volume was documented in any patient. Visual symptoms improved in 51.7% of patients. In the systematic review, the mean visual improvement was 36% (range: 25.8-42.5%). Conclusion SRS is an effective treatment for benign tumors invading the cavernous sinus. In this series, patients who underwent SRS as a primary treatment showed improvement in pre-existing cranial neuropathy and visual symptoms. Given the natural history of these tumors, which tend to grow and cause visual alternations, treating asymptomatic patients is a feasible approach worth considering for the appropriate patients.

Keywords: cavernous sinus; meningiomas; pituitary adenoma; radiosurgery; visual outcomes.

Figure 1. Scoping literature review

LILACS, Latin American and Caribbean Health Sciences Literature; SRS, stereotactic radiosurgery.

Figure 2. Tumor control rate at last follow-up in patients receiving surgery along with SRS vs. SRS alone

SRS, stereotactic radiosurgery.