Primary Care: Stereotactic Radiosurgery Plus Whole Brain Radiotherapy Versus Radiotherapy Alone for Patients with Multiple Brain Metastases

Reviewers: John Han-Chih Chang, MD
Source: International Journal of Radiation Oncology Biology Physics 1999; Volume 45: pages 427 - 434

Background

Brain metastases management has long been a significant issue in the management of cancer patients. Initially, the treatment of choice was supportive care alone. Currently, most patients are treated with fractionated whole brain radiation therapy (WBRT), which has extended survival to 3 - 6 months. For those with a solitary brain metastasis and controlled primary as well as systemic disease, surgery followed by WBRT has proved in a randomized setting to be the most efficacious treatment when compared to surgery or radiation alone1-3. However, the majority of patients with brain metastases have multiple lesions, are not medically operable or have metastatic disease in locations not amenable to surgical resection. Perhaps the next best option is stereotactic radiosurgery (SRS), when surgical resection is not possible. This precision radiation treatment has been utilized to deliver high doses of radiation to small areas attempting to minimize the normal tissue dose and maximize the tumor dose. The goal of this trial from the University of Pittsburg was to determine if SRS in addition to WBRT would improve the control rate of multiple metastases to the brain.

Summary/Critique/Conclusion

The data presented in this article was gathered from 27 patients randomized to receive WBRT (30Gy in 2.5Gy fractions) +/- SRS boost (16Gy to periphery of the tumor). Patients had 2 - 4 lesions, which were at the most 25 mm in greatest diameter. The initial planned accrual was 44 patients, but interim analysis demonstrated a very significant improvement in local control at 1 year in those that received SRS boost (100%) versus those that received WBRT alone (8%) (p = 0.0016). Median time to local failure was 36 and 6 months, respectively (p = 0.0005). This seems an unusual statistic slightly inflated difference, since the median survival was not significantly different at 7.5 and 11 months, respectively (p = 0.22). Thus, many of the patients in the WBRT + SRS arm were censored as deceased without local failure in the brain.

Some of the patients on the WBRT alone arm did receive SRS when they failed. This seemed to improve their median survival to be comparable to that of patients in the WBRT + SRS arm. Thus, as long as SRS was utilized, whether delayed or as part of the initial therapy, benefit was derived.