PV QA 4 - Poster Viewing Q&A 4
Purpose/Objective(s): Although more convenient and cost effective than competing radiotherapy modalities, the use of intraoperative radiation therapy (IORT) for breast cancer remains controversial. We utilized the National Cancer Database (NCDB) to analyze trends in IORT utilization.
Materials/Methods: We examined use of IORT over time as well as the patient demographic and facility related factors associated with the use of IORT. Patient characteristics included suitability for accelerated partial breast irradiation (APBI) by the 2009 ASTRO Consensus Statement, as well as eligibility for omission of radiotherapy based on the inclusion criteria for the Hughes CALGB 9343 trial.
Results: Among the 45,123 patients in the NCDB who received APBI between 2004-2014, 1,311 received intracavitary IORT. From 2004-2009, IORT accounted for 1.0% of all APBI treatments, but from 2010-2014 its proportion increased to 4.0%, with a peak of 8.6% in 2014. Prior to 2009, 38.7% of IORT cases were treated at academic centers, significantly less than non-academic centers (p<0.001). Conversely, 59.3% were performed at academic centers from 2009-2014, which was significantly more than non-academic centers within that timeframe (p<0.001). The majority of IORT patients (66.8%) lived within 20 miles of the treating facility, while 4.9% traveled >100 miles to be treated. Patients traveling >20 miles were more likely to be treated at academic centers (70.8%, P<0.001) but there was no difference in facility type when < 20-miles. Using the 2009 ASTRO APBI criteria, the proportion of patients deemed “suitable” for APBI increased from 14.3% in 2004 to 64.7% in 2014. Similarly, after 2009, the proportion of “unsuitable” IORT patients decreased from 40.7% to 20.4%. Based on post-operative pathology, 12.3% of “unsuitable” patients would have been upgraded to “suitable”, while 4.4% of “suitable” IORT patients would have been downgraded to “unsuitable”. 11.2% of patients were treated with IORT for DCIS, with no significant differences by year or facility type. Of IORT patients, the proportion eligible to omit radiation decreased from 14.2% in 2004 to 2.1-6.9% in 2010-2014, and was not significantly different by facility type.
Conclusion: Although IORT accounts for <5% of APBI treatments in this series, its use increased over 20-fold from 2009-2014. The increase coincides with publication of the ASTRO APBI Consensus Guidelines and TARGIT-A trial. The proportion of “unsuitable” APBI patients receiving IORT as sole radiotherapy decreased in the period after publication of the consensus statement. The majority of treatments were in “higher risk” patients for whom omission of radiotherapy is generally considered unacceptable. Uptake of the technique has been higher at academic centers. While the convenience of IORT removes distance as a barrier to care, the majority of patients receiving treatment live within 20 miles of the treating facility. Additional analysis is necessary to determine the primary drivers of IORT utilization.
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