Routine Use of Single Visit Online Adaptive Cone Beam Computed Tomography Guided Sim-Free Palliative Radiation Therapy

Purpose: Recent developments in cone beam computed tomography guided online adaptive radiation therapy (RT) enabled new fast workflows for palliative RT. Our previous work showed improvements in departmental logistics and patient satisfaction with the use of online adaptive RT compared with regular palliative workflows. The present study focused on experiences after routine use of this workflow and investigated predictors of treatment time to potentially increase efficiency and lower the logistic burden. Methods and Materials: Patients treated with 1 fraction of 8 to 12 Gy for nonmobile metastases were included. Data was collected on patient characteristics, treatment time, DICOM imaging, and treatment plans. Multiple regression was performed to identify significant predictor variables for treatment time. Treatment outcomes (6-12 weeks follow-up) were collected using the EQ-5D-5L quality-of-life questionnaire. Additionally, patient satisfaction and pain response (Numeric Rating Scale) were collected. Results: Of the 100 FAST-METS treatments included, 94 had complete time data. Patients spent on average 84 minutes (range, 50-135) at the department. The median treatment time was 29 minutes (range, 16-64). Exploratory results of the multiple regression showed that the Karnofsky Performance Score (KPS) was significant (P < .001) in predicting total treatment time and anatomic site was significant for predicting contour adaptation time (P < .05). Median in-room time for patients with a KPS ≥ 70 and easy anatomic site was 25 minutes. Ninety-three percent of patients prefer the same treatment workflow if treated again. In the EQ-5D-5L questionnaire, 52% of patients reported improvement in health. Pain decreased in 58% of patients at the 6-week follow-up. Conclusions: Cone beam computed tomography guided online adaptive RT improves efficiency and patient comfort in palliative RT. In this exploratory study, the KPS and anatomic sites were found predictors for treatment time and should be considered when introducing this workflow in another department. The majority (88%) of patients spent less than 2 hours in the department and more than 90% of patients were satisfied with this treatment.