What are your preferred target doses for bulky T4 rectal adenocarcinomas with extensive GU and anal sphincter involvement as well as common illiac and inguinal adenopathy, as part of total neoadjuvant therapy when future APR is planned?

In particular, many guidelines suggest a max point dose of 50Gy for small bowel but in cases of extensive disease how do you reconcile loops of bowel immediately adjacent to gross disease, most commonly encountered when primary tumor approaches the rectosigmoid junction or with frank common illiac adenopathy that persists even after prone positioning and optimized bladder filling especially in very thin patients?

1 Answer

Mednet MemberInvited Expert

Radiation Oncology · Memorial Sloan Kettering Cancer Center

Answered on · Updated on

Often what you think may be CI LAD is actually mesocolic LAD and will be removed at the time of surgery. If there is no internal or external iliac LAD that is likely the case and regardless the surgeons can easily remove them in most cases opposed to internal iliac nodes, which are a challenge due to bleeding.

First, there should be a discussion with the surgeon about the plan for the inguinal and "CI" LAD. My preference is a pre-op CXRT dose followed by limited surgical excision. Depending on the surgical risk, another option is definitive RT (SIB 62.5-70Gy in 25 fractions within a 45Gy microscopic dose and 50Gy high-risk microscopic dose) to the nodes and reserving surgery for incomplete response in the nodes down the road. The worst opti...

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