Adherence to Contouring and Treatment Planning Requirements Within a Multicentric Trial: Results of the Quality Assurance of the SAKK 09/10 trial

68Ga-PSMA PET/CT–Based Atlas for Prostate Bed Recurrence After Radical Prostatectomy: Clinical Implications for Salvage Radiation Therapy Contouring Guidelines

“…Increased dose to normal tissues is associated to acute and late GI and GU side effects that significantly decrease patient's quality of life. In fact, a retrospective quality assurance analysis from a randomized trial confirmed that an overlap of the CTV with rectal wall at the time of planning is associated with increased toxicity (22).…”

ESTRO ACROP guideline on prostate bed delineation for postoperative radiotherapy in prostate cancer

“…An accurate and precise delineation of the radiotherapy target volume is of particular importance to provide reproducible and reliable reporting, maximize oncological outcomes and minimize treatment-related toxicity. Variation in contour delineation among radiation oncologists is common and can affect the resulting treatment delivery and patient outcomes [9] , [30] , [31] , [32] . Several studies have shown that the use of guidelines and contouring atlases can improve inter-observer variability of both the target volume and OAR with additional evidence that these improvements in contour delineation can improve predicted tumour control and normal tissue complication probability [31] , [32] , [33] , [34] .…”

“…Additionally, the anterior rectal wall is more clearly marked on MRI, resulting in minimal discrepancies between observers compared with CT-only delineation. A central review of a phase 3 trial for salvage radiotherapy using CT-based delineation showed that limited adherence to treatment protocol recommendations (e.g., overlap of the CTV with rectal wall), was associated with a higher risk of toxicity and a trend toward worse biochemical control [9] . When MRI is used to aid CT-based CTV contouring, however, it is important to ensure an appropriate image fusion which often can be challenging due to differences in bladder and rectum volumes between the imaging modalities.…”

“…In prostate cancer patients treated with prostatectomy, the accurate target volume definition can be challenging given the absence of the prostate boundaries and a variable postoperative anatomy. Despite the existence of various prostate bed contouring guidelines [3] , [4] , [5] , [6] , [7] , the recommendations remain inconsistent resulting in considerable inter-observer variability in the treatment target delineation [8] , [9] , [10] . A contouring guideline on target volume delineation encourages a consistent application of prostate bed treatments across clinical trials, institutions, and individual clinicians.…”