Adoption of intensity-modulated radiation therapy for breast cancer in the United States

Abstract

Background: Although intensity modulation of the radiation beam has been shown to lower toxic effects for patients receiving whole-breast irradiation, relatively simple techniques may suffice. It is thus controversial whether such treatment justifies billing for intensity-modulated radiation therapy (IMRT).

Methods: We used the claims data to determine billing for IMRT from Surveillance, Epidemiology, and End Results-Medicare records from 2001 to 2005 for 26,163 women aged 66 years or older with nonmetastatic breast cancer treated with surgery and radiotherapy. The impact of individual covariates (demographic, health services, tumor, and treatment factors) on cost of treatment was assessed using the Wilcoxon two-sample test. Two-sided multivariable logistic regression was used to identify predictors for IMRT use. Cost of radiation was calculated in 2005 dollars. All statistical tests were two-sided.

Results: The number of patients with IMRT billing claims increased from 0.9% (49 of 5196) of patients diagnosed in 2001 to 11.2% (564 of 5020) in 2005. In multivariable analysis, IMRT billing was more likely for patients with left-sided tumors (odds ratio [OR] = 1.30, 95% confidence interval [CI] = 1.16 to 1.45), for those residing in a health service area with high radiation oncologist density (OR = 2.32, 95% CI = 1.47 to 3.68), for those treated at freestanding radiation centers (OR = 1.36, 95% CI = 1.20 to 1.53), or for those residing in regions where the Medicare intermediary allowed breast IMRT (OR = 10.87, 95% CI = 9.26 to 12.76, all P < .001). The mean cost of radiation was $7179 without IMRT and $15 230 with IMRT. IMRT adoption contributed to an increase in the mean cost of breast radiation from $6334 in 2001 to $8473 in 2005.

Conclusions: IMRT billing increased 10-fold from 2001 through 2005, contributing to a 33% increase in the cost of breast radiation. These findings suggest that reimbursement policy and practice setting strongly influenced adoption of IMRT billing for breast cancer.