What radiation dose would you use when giving definitive chemoradiation for inoperable rectal cancer with extensive invasion into gluteal musculature?

A rectal cancer this aggressive is not easy to control. Surgeons tell me the surgical options are not promising. Assuming this is a new diagnosis, I would employ a total neoadjuvant approach. I would start with chemotherapy in this case (not 5x5 followed by chemo a la RAPIDO). After 4+ months of chemo, I would re-image and re-present the case in a multidisciplinary treatment planning conference. If surgery is not likely, and radiation is therefore "definitive", I have given 59.4 Gy to gross disease with concurrent capecitabine. The plan would depend on the proximity of organs at risk and the patient's condition. If the patient is listed as probable for surgery, I would do pretty much the same thing but to 50.4 Gy. More likely, extensive tum...

Many patients with locally advanced rectal cancers may be operable with multi-specialty input (GI surgery, urology, plastic surgery, etc.). When I see a patient with locally advanced inoperable rectal cancer, the first decision point is whether the patient is suited for definitive treatment with curative intent or palliation of symptoms. Many patients fall into a third category, where aggressive treatment is offered even when the likelihood of cure is low. I think this patient falls into the third group.

When no surgery is anticipated, I treat these tumors to the dose-tolerance limits of tissues under consideration. For this patient, I will treat all at-risk structures initially to 45 Gy in 1.8 Gy fractions, followed by a boost to the GTV (...