# Stereotactic aspiration alone or Ommaya placement and aspiration followed by stereotactic radiosurgery for cystic brain metastasis: A systematic review and meta-analysis

## TL;DR

This study compares treatments for cystic brain metastases and finds that combining Ommaya placement, aspiration, and radiosurgery improves tumor control compared to aspiration and radiosurgery alone.

## Contribution

The study provides a meta-analysis showing that Ommaya placement plus aspiration and radiosurgery improves local control for cystic brain metastases.

## Key findings

- Combined Ommaya placement, aspiration, and SRS achieved 81.2% tumor control.
- Stereotactic aspiration plus SRS had 64.7% tumor control.
- Ommaya placement plus SRS had similar further intervention rates but higher complication rates.

## Abstract

Cystic brain metastases (BMs) are often more challenging to treat than solid BMs. Stereotactic cyst aspiration for volume reduction followed by stereotactic radiosurgery (SRS) is an alternative treatment modality that may benefit patients with large cystic BMs not favorable for SRS alone nor microsurgical resection.

Here, we perform a systematic review and meta-analysis of stereotactic aspiration alone or reservoir (Ommaya) placement plus aspiration followed by SRS for cystic BMs.

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we reviewed articles published between 1968 and December 31−th, 2022. We retained 10 studies reporting 280 patients.

Overall rate of tumor control for combined treatment of Ommaya placement plus aspiration plus SRS was 81.2% (62.5–99.9%, p < 0.001) and for stereotactic aspiration plus SRS was 64.7% (46.1–83.3%, p < 0.001). Overall rate of further intervention for combined treatment of Ommaya placement plus aspiration plus SRS was 15.8% (p = 0.08) and for stereotactic aspiration plus SRS was 14.8% (5.3–24.4%, p = 0.002). Overall complication rate for combined treatment of Ommaya placement plus aspiration plus SRS was 12.8% (2.3–23.3%, p = 0.01) and for stereotactic aspiration plus SRS was 1.5% (p = 0.12).

Combined treatment of Ommaya placement plus cyst aspiration plus SRS in cystic BMs yields better local control as compared to stereotactic aspiration plus SRS, with similar rate of further intervention between procedures. Aspiration of the cyst plus SRS should be considered for patients with cystic metastases not able to undergo open surgery or upfront SRS.

•Cystic brain metastases (BMs) are often more challenging to treat than solid BMs.•Combined treatment Ommaya placement + cyst aspiration + SRS in cystic BMs yields better local control as compared to stereotactic aspiration + SRS.•Aspiration of the cyst + SRS should be considered for patients with cystic BM not able to undergo open surgery or upfront SRS.

Cystic brain metastases (BMs) are often more challenging to treat than solid BMs.

Combined treatment Ommaya placement + cyst aspiration + SRS in cystic BMs yields better local control as compared to stereotactic aspiration + SRS.

Aspiration of the cyst + SRS should be considered for patients with cystic BM not able to undergo open surgery or upfront SRS.