Multifractional SBRT schedule not associated with poorer local control in spinal metastases

2011 ASTRO Annual Meeting

MIAMI - One- and 2-year OS rates were similar for patients who underwent multifractional stereotactic body radiation therapy compared with patients who underwent single daily fractions, according to results of a 2-year study at Mayo Clinic in Rochester.

In results presented in a poster at the 2011 ASTRO Annual Meeting, researchers analyzed 85 spinal lesions diagnosed in 66 patients from April 2008 to December 2010. Thirty-two lesions were treated with a single daily fraction to a median of 18 Gy, and 52 patients were treated with multiple daily fractions to a median of 24 Gy. Median spinal cord maximum dose was 12.6 Gy (7.8 Gy-17.3 Gy) in the single fractionation schedule and 17.6 Gy (8.6 Gy-44.3 Gy) in the multifractional schedule.

One-year OS was 55% in the single fractionation group and 51% in the multifractional group. Two-year OS was 33% vs. 41% in favor of the multifractional schedule.

At 2 years, local control rate as 80% in the single fraction group vs. 85% in the multifractional group. Two patients had local failure in the single fraction group compared with six in the multifractional group.

There were no differences in actuarial survival or local control between the groups.

There was one incident of grade-3 toxicity in each group.

Researchers said the multifractionated treatment schedule with epidural disease does not compromise local control rates, but further study is needed to determine long-term control and toxicity.

For more information:

Ahmed KA. #2167. Presented at: the 2011 ASTRO Annual Meeting; Oct. 2-6; Miami.

Disclosure: The researchers report no relevant financial disclosures.

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