Early clinical outcomes for 3 radiation techniques for brain metastases: focal versus whole-brain

To present our novel technique for brain metastases (low-dose whole brain radiation therapy [WBRT] with simultaneous integrated boost (SIB) and focal, frameless stereotactic intensity modulated radiotherapy [IMRT]) in the context of patterns of failure, dosimetry, acute toxicity, and overall survival for 3 different radiation techniques.

We retrospectively reviewed 92 patients undergoing radiation for brain metastases via the following: (1) "prophylactic" WBRT to a low dose (median 30 Gy) with an SIB to the gross tumor volume plus 2-3 mm margin (median dose 45 Gy) in 10-15 fractions; (2) focal, frameless image-guided stereotactic IMRT (S-IMRT) in 5 fractions to tumor only (median 30 Gy); or (3) conventional (c)WBRT using 2 lateral opposed beams in 10-15 fractions (30-37.5 Gy). The primary endpoints were local (LBC), distant (DBC), and total brain control (TBC) for each of the 3 types of brain radiation. Survival, toxicity, and dosimetry were reported as secondary endpoints.

LBC was achieved in 72%, 78%, and 56% for SIB, S-IMRT, and cWBRT, respectively. DBC (ie, no new brain metastases) was observed in 92%, 67%, and 81% for SIB, S-IMRT, and cWBRT, respectively. TBC (LBC + DBC) was 72%, 67%, and 56% for SIB, S-IMRT, and cWBRT, respectively. No statistical difference in overall survival was observed (P = .067), and only 1 patient experienced biopsy proven radionecrosis.

TBC after low-dose WBRT with SIB was acceptable and at least comparable to S-IMRT and cWBRT. SIB seems to be a safe and effective treatment strategy for patients with brain metastases and may efficiently combine the benefits of cWBRT and stereotactic radiosurgery.