Alexander K. Kwon MD, Presenter: Nothing to Disclose

Steven Joseph DiBiase MD, Abstract Co-Author: Nothing to Disclose

Brian Wang PhD, Abstract Co-Author: Nothing to Disclose

Samuel Lee Hughes MD, Abstract Co-Author: Nothing to Disclose

Although many studies have reported that hypofractionated stereotactic radiotherapy (HSRT) has comparable tumor control rates and survival rates for brain metastasis to sterotactic radiosurgery (SRS), standard dose prescription of HSRT is still under investigation. This retrospective review evaluated effectiveness and toxicity profiles for multiple levels of doses of HSRT.

Between 2004 and 2006, 49 lesions among 27 patients with a primary brain tumor or brain metastasis were treated with HSRT. Of these 49 lesions, 7 lesions were treated with SRT alone, 37 lesions received both Whole Brain Radiotherapy (WBRT) plus SRT boost, and 5 lesions received HSRT as a primary treatment plus WBRT salvage treatment. The median prescribed dose was 25 Gy (range 12-36 Gy) by median 5 fractions (range 3-6 fractions) to median 85% iso-dose line (range 50% - 100%). The median maximum tumor dimension and treatment volume were 12.7 mm (range 4.8-51.6 mm) and 0.86 cc (range 0.05-58.91 cc, respectively. The median follow-up interval was 5.1 months (range 0.9-18.6 months). The multiple factors of overall survival (OS), local tumor control and overall tumor control were included in the statistical analysis.

The median overall survival time was 10.8 months, and 62.9% died of disease progression. After HSRT treatment among 35 brain lesions less than 20 mm, 10 lesions had complete response, 8 lesions had partial response, 13 lesions had stable disease and 4 lesions had progressive disease. Local tumor control rates were 88.6%. In brain lesions over 20 mm, local tumor control rates were 64.3% (Table 1). Tumor volume under 1 cc (p=0.011) was a statistically significant factor for local tumor control (Table 2). Among 27 patients, 2 patients had CTCAE grade III adverse events.

The HSRT dose 25-35 Gy has clearly effective tumor control rates and survival rates with less adverse events compared to SRS. But dose standardization is much needed.

Kwon, A, DiBiase, S, Wang, B, Hughes, S, Multiple Doses and Toxicity Profiles of Hypofractionated Stereotactic Radiotherapy for the Treatment of Patients with Brain Lesions.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/6001467.html