Background
Several new prostate cancer treatments emerged since 2000, including two radiotherapies with similar efficacy at the time of their introduction: intensity-modulated radiotherapy (IMRT) and stereotactic body radiation therapy (SBRT). We sought to compare their early adoption patterns and identify factors associated their use.
Methods
Using Surveillance, Epidemiology, and End Results (SEER)-Medicare, we identified prostate cancer patients treated with radiation during the five years after IMRT introduction (2001–2005) and five years after SBRT introduction (2007–2011). Our outcome was the use of new radiation therapy (i.e., IMRT or SBRT) compared with the existing standard radiation therapies at that time. We fit a series of multivariable hierarchical logistic regression models accounting for patients nested within health service areas to examine factors associated with new radiation therapy use.
Results
In 2001–2005, 5680 men (21%) received IMRT compared with standard radiation (n=21,555). Men receiving IMRT were older, had higher grade tumors, and lived in more populated areas (p<0.05). In 2007–2011, 595 men (2%) received SBRT compared with standard radiation (n=28,255). Men receiving SBRT were more likely to be white, had lower grade tumors, lived in more populated areas, and were more likely to live in the Northeast (p<0.05). Adjusting for cohort demographic and clinical factors, the early adoption rate for IMRT was substantially higher than for SBRT (44% versus 4%, p<0.01).
Conclusions
There is a stark contrast in the adoption rates of IMRT and SBRT at the time of their introduction. Further investigation of the nonclinical factors associated with this difference is warranted.