The Role of Facility Variation on Racial Disparities in Use of Hypofractionated Whole Breast Radiotherapy

INTRODUCTION: Hypofractionated radiotherapy is a less burdensome and less costly approach that is efficacious for most patients with early-stage breast cancer. Concerns about racial disparities in adoption of medical advances motivate investigation of the use of hypofractionated radiation in diverse populations. The goal of our study was to determine whether hypofractionated whole breast radiotherapy after breast conserving surgery was being similarly used across racial groups in the state of Michigan. METHODS AND MATERIALS: A prospectively collected statewide quality consortium database from 25 institutions was queried for breast cancer patients who completed hypofractionated (HF) or conventionally fractionated (CF) whole breast radiotherapy (RT) from 1/2012-12/2018. We used patient-level multivariable modeling to evaluate associations between HF use and race, controlling for patient and facility factors, and multilevel modeling to account for patient clustering within facilities. RESULTS: Of 9,634 patients analyzed, 81% self-reported race as White, 17% as Black and 2% as Asian, similar to statewide and national distributions. 31.7% of Whites were treated at teaching centers compared to 66.7% of Blacks and 64.8% of Asians. In 2018, HF was utilized in 72.7% of Whites versus 56.7% of Blacks and 67.6% of Asians (p=0.0411). On patient-level multivariable analysis, Black and Asian races were significantly associated with a lower likelihood of HF receipt (p\u3c0.001), despite accounting for treatment year, age, laterality, BMI, breast volume, comorbidities, stage, triple-negative status, IMRT use, teaching center treatment, and 2011 ASTRO Hypofractionation Guideline eligibility. On multilevel analysis, race was no longer significantly associated with HF receipt. CONCLUSIONS: We observed that Black and Asian patients receive hypofractionated RT less often than Whites, despite more frequent treatment at teaching centers. Multilevel modeling eliminated this disparity, suggesting that differences in facility-specific HF use appear to have contributed. Further inquiry is needed to determine if reduction of facility-level variation may reduce disparities in accessing HF treatment

The role of facility variation on racial disparities in use of hypofractionated whole breast radiotherapy

Background: Concerns about racial disparities in the adoption of medical advances motivate investigation of the use of hypofractionated radiotherapy, a less burdensome and less costlyapproach that is efficacious for most patients with early-stage breast cancer. Methods: A prospectively collected statewide quality consortium database from 25 institutions was queried for breast cancer patients who completed hypofractionated (HF) or conventionally fractionated whole breast radiotherapy (RT) from 1/2012-12/2018. We used patient-level multivariable modeling to evaluate associations between HF use and race, controlling for patient and facility factors, and multilevel modeling to account for patient clustering within facilities. Results: Of 10,318 patients analyzed, 80% self-reported their race as White, 18% as Black, and 2% as Asian, similar to statewide and national distributions. 31% of Whites were treated at academic centers compared to 65% of Blacks and 65% of Asians. In 2018, HF was utilized in 75% of Whites versus 60% of Blacks and 68% of Asians. On patient-level multivariable analysis (see Table), Black and Asian race were significantly associated with a lower likelihood of HF receipt, despite accounting for treatment year, age, laterality, BMI, breast volume, comorbidities, stage, triple-negative status, IMRT use, academic center treatment, and 2011 ASTRO Hypofractionation Guideline eligibility. On multilevel analysis, race was no longer significantly associated with HF receipt. Conclusions: We observed thatBlack and Asian patients receive hypofractionated RT less often, despite more frequent treatment at academic centers. Multilevel modeling eliminated this disparity, suggesting that differences in facility-specific HF use may contribute. Further inquiry is needed to determine if reduction of facility-level variation may reduce disparities in accessing HF treatment

The value of performance metrics in a large statewide consortium: using planning target volumes towards improvements in breast planning.

Purpose: While several ICRU reports recommend planning target volumes (PTVs) in radiation therapy, the frequency of PTV use in routine clinical practice for patients who have undergone breast-conserving surgery is not known. A statewide consortium, focused on quality improvement, evaluated whether or not a PTV was created for the lumpectomy cavity for these patients. Methods: Baseline data regarding lumpectomy cavity PTV delineation use was acquired from 22 institutions for patients who underwent breast-conserving surgery from 2011 through mid-2016. In 2017, a consortium- wide performance metric was established requiring PTVs for the lumpectomy cavity with the purpose of ensuring adequate target coverage when cardiac dose is considered. The PTV delineation rate was evaluated before and after introduction of the performance metric. Starting in August 2017, the expansion size was captured. Results: For patients who completed radiotherapy before the intervention (2011- mid-2016; N = 6278), 35.0% had a PTV delineated. For patients who completed radiotherapy after the intervention was required (2017; N = 1890), this percentage increased to 77.8%. During that time, PTV adoption rates varied by institution (N = 22) with 9 institutions delineating a PTV for 90% or more of their patients, 8 between 50-90%, and 5 less than 50% at the end of 2017. The median PTV expansion used by institutions was 1 cm (range 0.1-2 cm). Conclusion: Introduction of a consortium-wide performance metric was an effective intervention, increasing the PTV delineation rate for the lumpectomy cavity for radiation therapy patients who have undergone breast-conserving surgery. This increase in PTV use will allow the consortium to make target dose homogeneity and coverage recommendations which may aid in weighing clinical tradeoffs between target and heart doses. Future work will investigate the relationship between lumpectomy cavity expansion size as a function of whether or not daily or weekly imaging is used amongst clinics within the consortium