ESTRO 38 Abstract book

S628 ESTRO 38

Purpose or Objective The purpose of this study is to analyze errors detected in the pretreatment plan review (PTPR) and evaluate the effectiveness of the quality assurance checking program implemented at the Department of Radiation Oncology, Shuang Ho Hospital, Taipei Medical University. Material and Methods An “error” is defined as an event that has been detected in the pretreatment plan review or after the completion of the plan check, which would lead to some problems to a patient undergoing radiotherapy if undiscovered. The pretreatment plan review is a key safety check and can detect a high percentage of errors. Through this study, we can evaluate and monitor the quality assurance of the PTPR in our institution.The errors recorded between August 2017 and May 2018 were analyzed and classified.Descriptive statistics include error rates of single, mutiple and overall , and the staff compliance rate for plan evaluation. Results From August 2017 to May 2018, there were 139 errors reported in PTPR among a total of 1087 plans, resulting in single error rate of 11%, mutiple error rate of 1% and overall error rate 12% in average. The mean compliance rate was 98.2 %. The incidence of various errors was presented in the figure 1. Monthly error rates and compliance rate were shown in the figure 2.

1 University College London, Division of Surgery and Interventional Science, London, United Kingdom

Purpose or Objective Clinical practice guidelines should be a central determinant of treatment choice, and must therefore be based on well-controlled clinical studies, ideally randomised clinical trials (RCTs). In 2018, evidence-based guidelines were published as the result of a collaboration among the American Society of Clinical Oncology (ASCO), the American Urological Association (AUA), and the American Society for Radiation Oncology (ASTRO). Eight key questions were addressed regarding hypofractionated radiation therapy as treatment for localised prostate cancer [Morgan et al PMID: 30322661]. An analysis was made of the publications supporting these guidelines to determine how many reported level-1 evidence from RCTs, as this is the standard applied to chemotherapy and hormonal therapy. Material and Methods All 106 references cited in the guidelines were scrutinized and tabulated according to level of evidence (RCT or not) and which of the statements of the eight key questions (KQ) they addressed. Results Ten RCTs provided evidence for the guidelines. Of the 18 statements, 7 are not directly supported by evidence from RCTs (7/18 or 39%). There is no evidence from RCTs to support any of the statements regarding ultrahypofractionation versus conventional fractionation (KQ3, three statements), different ultrahypofractionation regimens compared with one another (KQ4, three statements), and a comparison of treatment volumes in terms of prostate cancer control and toxicity (KQ6, one statement). Furthermore, the key question regarding use of IGRT in terms of prostate cancer control, toxicity, and quality of life (KQ7, one statement) was supported by a non- comparative phase II study embedded within an RCT and published as a meeting abstract; and the key question on the use of non-modulated 3-D CRT techniques when used with delivery of moderately or ultrahypofractionated prostate EBRT was supported by one RCT of 215 men. Conclusion More than one-third of the 2018 ASTRO/ASCO/AUA evidence-based guidelines are not based on level-1 evidence from RCTs. Clinicians and patients should be aware that current guidelines for use of ultrahypofractionated EBRT in the treatment of localised prostate cancer are substantially based on sub-optimal evidence. This is important as it is known that, in the long term, radiotherapy reduces the incidence of clinical progression and metastatic disease when compared with active monitoring in men with low and intermediate risk localised prostate cancer [Hamdy et al PMID: 27626136]. However, any benefits of ultrahypofractionation need to be weighed against the potential harms on quality of life such as adverse outcomes in bowel function [Donovan et al PMID: 27626365]. Large randomized clinical trials evaluating ultrahypofractionation are urgently required.

Conclusion The pretreatment plan review is a key safety check and can reduce but never eliminate the incidence of errors. Through this study, we can evaluate and monitor the quality assurance of the PTPR in our institution. PO-1132 RCT evidence in 2018 ASTRO/ASCO/AUA guidelines for hypofractionated radiotherapy in prostate cancer N. Williams 1 , C. Orczyk 1