Stereotactic radiosurgery for intracranial and spinal adenoid cystic carcinoma: systematic review and illustrative case presentation.

Abstract

Purpose: Adenoid cystic carcinoma (ACC) is a rare, aggressive malignancy with a predilection for perineural spread and distant metastases. Given the limited but emerging evidence on the role of stereotactic radiosurgery (SRS) in managing intracranial and spinal ACC, a systematic review was deemed necessary to synthesize relevant parameters related to clinical features and management of ACC patients, SRS treatment characteristics, and clinical outcomes across published studies.

Methods: This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive search of the PubMed, Scopus, and Embase databases was performed to identify studies evaluating patients with histologically confirmed diagnoses of intracranial and/or spinal ACC who were treated with SRS. Additionally, a unique illustrative case was presented.

Results: A total of 129 patients and 211 lesions with ACC were identified from 16 studies published between 1992 and 2025. Patient ages ranged from 10 to 85 years. Lesions were mostly in the intracranial space (n = 194; 91.9%), followed by the spinal column (n = 17; 8.1%). Standalone SRS was administered as primary treatment in 108 lesions (57.1%). Six of eight studies documented a median prescription dose ≥ 15 Gy, while the mean calculated dose among case reports/series with individualized data was 20.8 Gy (SD = 10.4 Gy). Two of four studies recorded a median maximum tumor dose ≥ 30 Gy. Most treatment plans were delivered in a single fraction. Local tumor control (LTC) was achieved in 210/211 lesions (99.5%) over time, although 32/201 lesions eventually experienced local failure (15.9%). LTC duration ranged from 1 to 326 months, and overall survival ranged from 0 to 354 months. A 43-year-old male with concurrent intracranial and spinal ACC treated with CyberKnife SRS is presented.

Conclusions: SRS offers favorable LTC for intracranial and spinal ACC, supporting its role as a precise, advanced radiation modality in this challenging context.