Stereotactic radiation for prostate cancer lowered costs, increased toxicity

Issue: June 25, 2014

Stereotactic body radiation therapy for prostate cancer lowered treatment costs but increased the rate of genitourinary toxicity compared with intensity-modulated radiation therapy, according to results of a retrospective study.

The analysis included 4,005 Medicare beneficiaries aged at least 66 years treated for prostate cancer between 2008 and 2011. Of these men, 1,335 underwent stereotactic body radiation therapy (SBRT) and 2,670 underwent IMRT. Researchers matched the men based on whether they received 6, 12 or 24 months of follow-up.

Overall, mean treatment costs associated with SBRT were lower than those with IMRT ($13,645 vs. $21,023).

However, more men who underwent SBRT experienced genitourinary toxicity 6 months (15.6% vs. 12.6%; OR=1.29; 95% CI, 1.05-1.53) and 24 months (43.9% vs. 36.3%; OR=1.38; 95% CI, 1.12-1.63) after treatment initiation compared with men who underwent IMRT. The most common causes of genitourinary toxicity were urethritis, urinary incontinence and obstruction.

Anthony V. D’Amico

In an accompanying editorial, Anthony V. D’Amico, MD, PhD, chief of the division of genitourinary radiation oncology at Brigham and Women’s Hospital and Dana-Farber Cancer Institute, wrote that the data are limited by the lack of patient randomization; analyses that were not adjusted for baseline genitourinary and gastrointestinal function, dose fractionation schemes and dose volume constraints; and the inability to evaluate toxicity grade.

“Despite the potential limitations of the study by Yu et al … the results of the current study should raise our awareness that the potential for an increase in clinically significantly genitourinary toxicity with SBRT as compared with IMRT exists,” D’Amico wrote. “As the authors allude to in their concluding remarks, I would also recommend that until the results of the Swedish randomized control trial [ISRCTN45905321] are available to provide data about the relative efficacy and toxicity among men treated with IMRT vs. accelerated radiation therapy, accelerated radiation therapy regimens utilizing cyberknife or SBRT for prostate cancer should only be performed in the setting of well-designed clinical trials.”

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Disclosure: D’Amico reports no relevant financial disclosures. See the study for a full list of the researchers’ relevant financial disclosures.