Trends in the use of proton beam therapy among newly diagnosed cancer patients in the United States.
6551 Background: Proton Beam Therapy (PBT) is a potentially superior radiotherapy technology for tumors with complex anatomy surrounded by sensitive tissues and for childhood cancers where sparing surrounding normal tissue is better achieved than with photon radiotherapy. The first conditions for payment of PBT claims went into effect in 2009. In 2014, the American Society of Radiation Oncology categorized PBT clinical indications into Group 1, for which health insurance coverage is recommended, and Group 2, for which coverage is recommended only if additional requirements are met. Methods: We evaluated 21,920 newly diagnosed patients in the National Cancer Database (NCDB) who received PBT between 2004 and 2016. Joinpoint analyses were used to evaluate the Annual Percent Change (APC) in the number and characteristics of patients treated with PBT. Results: The number of patients treated with PBT in NCDB facilities increased from 1,114 in 2004 to 3,173 in 2016 (APC = 8.78, p < .001), due mainly to increases in Group 1 cancers after 2010 (from 271 patients in 2010 to 1,124 in 2016, APC = 26.4, p < .001). The number of Group 2 patients treated with PBT increased slower (from 937 in 2004 to 2,049 in 2016, APC = 6.1, p < .05). Breast and prostate cancers were most common, although trends varied substantially by cancer site. Between 2010 and 2016, receipt of PBT increased for breast cancer patients from 40 in 2010 to 405 in 2016 (APC = 48.5, p < .001), but decreased for prostate cancer patients from 1,205 in 2011 to 680 in 2016 (APC = -14.06, p < .001). While most of Group 1 patients had private insurance coverage (59.3% of patients treated in 2016), Medicare was the most common primary insurance type among Group 2 patients (50% of patients treated in 2016). Conclusions: The number of newly diagnosed cancer patients treated with PBT has increased between 2004 to 2016 in the US, with a sharp increase for cancers with clinical indications for health insurance coverage since 2010. While most of these patients have private insurance coverage, the steady increase in the number of patients being treated with PBT for cancers with additional requirements for health insurance coverage is primarily in those with Medicare coverage.