Main Session
Sep
29
PQA 06 - Genitourinary Cancer, Gynecological Cancer, and Health Care Access and Engagement
Presenter(s)
Paul Ramia, MD - Cleveland Clinic Abu Dhabi, Abu Dhabi, Abu Dhabi
P. Ramia, E. Mayyas Sr, C. Hajj, W. Hassen, S. Ahmed, S. Al Nowais, H. Abdul Khalek, M. D'Almeida, and F. B. Geara; Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
Purpose/Objective(s):
Online adaptive radiation therapy (ART) enables daily plan re-optimization to account for anatomic variation and organ motion. Real-world clinical outcome data following large-scale implementation remain limited. We report here weekly acute toxicity grades during radiation treatment from the first 100 consecutive prostate cancer patients treated with ETHOS-based online adaptive radiation therapy at a quaternary academic centre.Materials/Methods:
All referred prostate cancer patients were treated with ETHOS-guided adaptive external beam radiation therapy. Acute physician-reported genitourinary (GU) and gastrointestinal (GI) toxicity were recorded on a weekly basis during radiation treatment using standard grading criteria (CTCAE 5.0). Data was retrospectively collected and multivariable logistic regression was performed to evaluate predictors of GU grade =2 toxicity.Results:
Treatments included definitive (64%) and salvage (36%) courses. Pelvic nodal irradiation was delivered in 53% of patients. A total of 2,593 fractions were delivered, of which 2,459 (94.8%) the daily adapted plan was selected. All predefined bladder and rectal dose constraints were met in 100% of treatments. Mean treatment time per session was 27.1 ± 4.4 minutes. Acute GU grade =1 and =2 toxicity occurred in 50% and 24% of patients, respectively. Acute GI grade =1 and =2 toxicity occurred in 30% and 3% of patients, respectively. No acute Grade 3 toxicity occurred during the treatment period. On multivariable analysis, moderate to severe baseline urinary symptoms (IPSS =8) independently predicted GU grade =2 toxicity (OR =4.06, p=0.02). Age, pelvic nodal irradiation, and diabetes were not independently associated with GU toxicity. No variables independently predicted GI toxicity.Conclusion:
Implementation of ETHOS-based online adaptive radiation was associated with low rates of clinically significant acute toxicity, including 3% grade 2 GI and no grade 3 toxicity. High adaptive utilization rate (94.8%), and universal constraint compliance support the benefit of adaptive prostate radiation therapy in routine clinical practice. Baseline urinary function remains the primary predictor of acute GU toxicity.