SU‐E‐P‐09: Compliance With Evidence‐Based Treatment Planning DVH Guidelines In An Academic Multi‐Site Radiation Oncology Practice Setting

Purpose: To evaluate the compliance with evidence-based treatment planning organ-at-risk (OAR) guidelines in a single institution with four practice sites. Methods: Two hundred thirteen head and neck cancer patients treated between September 2009 and September 2013 were retrospectively selected. Consensus treatment planning guidelines, including OAR dose constraints, were established based on institutional experience and published data. Data spanned a time period of 2 years prior to (n=112) and 2 years post-enactment (n=101) of the guidelines. We investigated the differences in the frequency with which (1) OARs were contoured and (2) OAR DVH goals were met. Trends in the proportion with OAR contours over time was tested using linear regression. Trends in the proportion of contoured OARs achieving clinical DVH goals were similarly tested. The proportion of patients contoured and meeting DVH goals before and after guidelines was compared using a test of proportions. Results: When the proportion of cases with OAR contours before and after guidelines were compared, we observed an increase from 75% to 87% (p=0.02) for the brainstem, decrease from 97% to 88% (p=0.01) for the cord and increase from 47% to 77% (p<0.001) for the mandible. For the proportion of cases with OAR contours in which clinicalmore » goals were met, a significant decrease from 99% to 90% was observed for the cord V48<0.3% (p=0.001). A significant decrease in the proportion of cases with left parotid contours (from 92% to 73% (p=0.03)) was observed over 2 years after guideline enactment and the proportion meeting the clinical DVH goal of V30<50% increased significantly from 36% to 50% (p=0.007) over the 2 years after guidelines. Conclusion: The enactment of OAR planning guidelines resulted in an increase in OAR contour compliance, overall. In cases with OAR contours, there was little to no change in the proportion that met clinical goals.« less