Stereotactic Radiosurgery (SRS) Dose Selection for < 2 cm Brain Metastases: The Influence of Planned Whole Brain Radiation Therapy (WBRT)

Diana Stripp, MD
University of Pennsylvania Cancer Center
Last Modified: November 7, 2001

Presenter: Young, AB
Presenter's Affiliation: Neurosurgery, University of Kentucky, Lexington, KY
Type of Session: Scientific

Background

Based on RTOG 9005, 24 Gy as SRS dose for treatment of brain metastases < 2cm has become the national standard for which no additional therapy (e.g. WBRT) was planned.

This analysis reviews a single institutional protocol experience utilizing 20 Gy SRS in patients with newly diagnosed and/or recurrent < 2 cm brain metastases.

Materials and Methods

Between 11/92 and 4/00, 96 pts with 234 newly diagnosed (82%) or recurrent (18%) < 2 cm brain metastases were treated with 20 Gy of SRS.

60% received planned WBRT in combination with SRS.

Results

The overall tumor control rates at 8, 13, and 26 months were 98%, 87%, and 73% respectively.

On multivariate analysis the most significant indicator of tumor control was the addition of planned WBRT vs no planned WBRT. Patients receiving planned WBRT had a 13 month tumor control rate of 94% as compared to 79% for those not receiving planned WBRT (p = 0.03).

Complication: 6% with RTOG grade 3/4 toxicity.

Author's Conclusions

20 Gy of SRS is highly effective when combined with planned WBRT for pts with brain metastases < 2cm.

For patients being treated for recurrences and/or for which WBRT is not planned, metastases should be treated with 24 Gy as determined by RTOG Study 90-05.

Clinical/Scientific Implications

In selected patients with brain metastases, the addition of SRS boost of 20Gy to WBRT is highly effective palliation. In patients without planned WBRT, the SRS dose should remain 24 Gy for brain mets < 2cm.

Oncolink's ASTRO Coverage made possible by an unrestricted Educational Grant from Bristol-Myers Squibb Oncology and Pharmacia Oncology.