Put to bed.

Top Line: Who wouldn’t benefit from contouring guidelines for adjuvant radiation post-radical cystectomy?

The Study: This guidelines study retrospectively assessed contouring recommendations (CTV-IC-2016) across 72 patients who received post-cystectomy IMRT on a prospective phase 2 Belgian trial. Clinical treatment volumes (CTV) included the common, internal, and external iliac arteries + 5 mm as well as the obturator and presacral spaces with a 12 mm expansion for the planning target volume. Importantly, the cystectomy bed was included only in the instance of a positive margin. Of 16 pelvic failures in 10 patients (14%), 13 were outside the CTV, 10 received <45 Gy, and 6 were in a cystectomy bed not included due to negative margin resection. After an extremely thorough mapping of all of these failures, updates to contouring guidelines were made. Drum roll please…this international committee now recommends inclusion of the common iliacs as well as the cystectomy bed regardless of margin status and to not crop the CTV from bowel.

TBL: This patterns of failure analysis provides evidence-based recommendations for CTV delineation for adjuvant radiation for bladder cancer. | Verghote, Pract Radiat Oncol 2022