In what situations can short course RT (5 Gy x 5fx) be used instead of chemoRT for rectal cancer?

My take? Preop short course RT is grossly underutilized in the US for locally advanced rectal cancer.

Progress is slow but we are getting there; the 2019 version of the NCCN guidelines lists SCRT followed by resection as a standard option for patients w/ T3 or N+ disease as long as the CRM is clear by MRI. Representing a change from prior versions of the guidelines- it also lists SCRT followed by 12-16 weeks of chemotherapy followed by surgery as an option for patients with T4 disease or those with an involved CRM by MRI.

As long as we wait at least 6-8 weeks following SCRT to do surgery- we should have the same downstaging and sphincter-sparing potential of long course CRT, at least if we believe phase III data published so far. As mentioned...

Every locally advanced rectal cancer patient is a candidate for short course radiation, especially short course radiation therapy followed by systemic chemotherapy as part of a 'total neoadjuvant therapy' approach.

For the patient, this SC-TNT treatment means:

-> less visits for radiation therapy

-> less diverting ileostomy time

-> more patients receiving planned chemotherapy than 'traditional' chemoXRT->surgery->adj chemo.

For the American radiation oncology department

-> Either less revenue (current payment model) or less cost (alternative payment model)

As mentioned previously by Dr. Mamon and others; there is a DIFFERENT side effect profile. The patients can develop diarrhea, proctitis, tenesmus in the subsequent two weeks after radiation ther...

I think it's reasonable to use in any rectal cancer where you are not concerned about a possible positive margin. The MRC CR07 trial clearly showed that patients in any location of tumor (lower, mid, upper) derived some benefit in local control from short course radiation when compared to selective post-op chemoradiation. Additionally, it remains controversial to what degree chemoradiation improves sphincter preservation. While our institution certainly likes to think that it impacts spincter preservation (and thus our continued use of it), the reality is that for many patients, the surgeon already has in mind what operation they will do whether there is downstaging or not, often based on the location of a pre-treatment distal India ink tat...

The answers to this question might well be changed in one to two years, when outcome data from the PROSPECT and RAPIDO trials are released. There are some "what ifs" to keep in mind.

The PROSPECT and RAPIDO trials both compare standard preoperative long course CRT with a regimen that reduces the time allocated to RT and fills the time with some of the cycles of multi-drug chemo that would normally be given postoperatively. In PROSPECT there is no RT in the experimental arm; in RAPIDO short course RT is given a week before the preoperative chemo. Both the PROSPECT and RAPIDO studies have experimental arms that are more cost effective than the control arm, so an unequivocal tie in all aspects of outcome will favor the experimental arm. In bot...

I think the indication is evolving with ongoing studies trying to integrate neoadjuvant chemo with this hypofractionation regimen.

At present, we sometimes use it for elderly patients with upper rectal cancers only.

We have used it for recurrent disease reirradiation with SBRT using Cyberknife-6 Gyx5 on alternate days. Colostomy is a must.