Abstract P1-15-04: The adoption of hypofractionated whole breast irradiation for early-stage breast cancer: A national cancer data base analysis
Authors: Wang Elyn H , Mougalian Sarah S , Soulos Pamela R , Rutter Charles E , Evans Suzanne B , Haffty Bruce G , Gross Cary P , Yu James B 
Published: May 2015

Purpose

Hypofractionated whole breast radiation therapy (hypofractionation) for early-stage breast cancer is a treatment innovation that is both supported by high quality randomized trial evidence and clinical guidelines, and is more cost effective and convenient than conventional fractionation. However, whether hypofractionation has been adopted nationally, and what factors are related to its adoption, are unknown.

Methods

We performed a retrospective study of breast cancer patients in the National Cancer Data Base from 2004-2011 who were treated with radiation therapy and met eligibility criteria for hypofractionation. We used logistic regression to identify factors associated with receipt of hypofractionation (vs. conventional fractionation).

Results

We identified 13,271 (11.7%) and 99,996 (88.3%) women with early-stage breast cancer who were treated with hypofractionation and conventional fractionation, respectively. The use of hypofractionation increased significantly, with 5.4% of patients receiving it in 2004 compared with 22.8% in 2011 (P&lt;0.001 for trend). Patients living &gt;50 miles from the cancer reporting facility had increased odds of receiving hypofractionation (OR 1.57 [95% CI 1.44-1.72], p&lt;.001).

Adoption of hypofractionation was associated with treatment at an academic center (p&lt;0.001) and living in an area with high median income (p&lt;0.001). Hypofractionation was less likely to be used in patients with high risk disease, such as increased tumor size (p&lt;0.001) or poorly differentiated histologic grade (p&lt;0.001).

Adjusted odds ratios for receipt of conventional fractionation vs hypofractionationFeature (Reference)OR (95% CI)p-valueFacility Type (Academic)Community0.38 (0.35-0.42)&lt;0.001Comprehensive Community0.51 (0.48-0.53)&lt;0.001Other0.64 (0.52-0.78)&lt;0.001Facility Location (South)Northeast0.93 (0.88-0.99)0.02Midwest1.04 (1.00-1.11)0.07West1.69 (1.59-1.78)&lt;0.001Age in yrs (50-59)60-691.22 (1.16-1.29)&lt;0.00170-791.77 (1.66-1.89)&lt;0.001&gt;=803.12 (2.88-3.38)&lt;0.001Race (White)Black0.96 (0.89-1.05)0.41White Hispanic1.23 (1.10-1.36)&lt;0.001Other1.23 (1.13-1.34)&lt;0.001Primary Payor (Private insurance)No insurance1.16 (0.96-1.41)0.11Medicaid0.97 (0.86-1.10)0.71Medicare1.05 (1.00-1.11)0.05Other government0.81 (0.63-1.05)0.12Unknown1.22 (1.03-1.44)0.02Median Income Quartile (&lt;$30 000)30 000 - 35 0000.95 (0.87-1.04)0.3035 000 - 45 9990.97 (0.90-1.06)0.54&gt;= 46 0001.25 (1.16-1.35)&lt;0.001Unknown1.04 (0.86-1.25)0.70Urbanization (Metro)Urban0.88 (0.83-0.95)0.001Rural1.10 (0.99-1.22)0.07Distance from reporting facility (&lt;50 miles)&gt;=50 miles1.57 (1.44-1.72)&lt;0.001Unknown1.13 (0.91-1.40)0.27Year of Diagnosis (2004)20051.03 (0.92-1.14)0.6520061.11 (1.00-1.24)0.0520071.31 (1.18-1.45)&lt;0.00120081.99 (1.80-2.19)&lt;0.00120092,88 (2.62-3.15)&lt;0.00120104.10 (3.62-4.64)&lt;0.00120115.48 (4.83-6.21)&lt;0.001Grade (Well-differentiated)Intermediate0.94 (0.89-0.97)&lt;0.01Poor0.86 (0.80-0.91)&lt;0.001Undifferentiated1.03 (0.5-1.63)0.89Unknown0.90 (0.82-0.99)0.04Tumor Size (&lt;10 mm)10-29 mm0.90 (0.87-0.94)&lt;0.00130-49 mm0.71 (0.62-0.80)&lt;0.001&gt;=50 mm0.94 (0.67-1.32)0.76Unknown0.63 (0.42-0.95)0.03

Conclusions

The use of hypofractionation is rising and is associated with increased travel distance and treatment at an academic center. Further adoption of hypofractionation may be tempered by both clinical and non-clinical concerns.

Citation Format: Elyn H Wang, Sarah S Mougalian, Pamela R Soulos, Charles E Rutter, Suzanne B Evans, Bruce G Haffty, Cary P Gross, James B Yu. The adoption of hypofractionated whole breast irradiation for early-stage breast cancer: A national cancer data base analysis [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-15-04.