Conventional Chemoradiation Therapy Appropriate for Rectal Cancer Treatment

Noam VanderWalde, MD, MS, West Cancer Center, Memphis, Tennessee, debates that conventional chemoradiation therapy followed by total mesorectal excision and adjuvant chemotherapy is the correct approach for treating rectal cancer at the 2019 Great Debates and Updates in Gastrointestinal Malignancies meeting.

Transcript:

Noam VanderWalde:  I'm Noam VanderWalde. I am a radiation oncologist and associate professor at the West Cancer Center and University of Tennessee, in Memphis, Tennessee. Today, I spoke about the optimal radiation fractionation scheme for rectal cancer. This is actually a somewhat controversial topic and really kind of depends on where you live in the world.

Essentially, the debate on using short course radiation therapy, which is a one-week course, versus long course chemo radiation therapy. I went over the clinical trials that actually looked at this. I updated everybody on four randomized clinical trials. Two of those trials were done in the pre-total neoadjuvant era and seemed to show that there was no difference in terms of local control or overall survival, between short course radiotherapy and long course chemo radiation therapy.

However, past ZR rates, and down staging and possibly R0 resections seem to favor the longer course of chemo radiation. However, in more recent trials looking at using a total neo adjuvant therapy approach where chemotherapy is actually given before surgery, and where surgery is actually delayed after short course radiotherapy, there does not seem to be as much of a difference in terms of past ZR rates or R0 resections.

Actually, some of the best data seems to be in using short course radiotherapy, followed by a delay to surgery. In this new era, it's possible that we should be using more short course radiation therapy for our patients who are getting total neoadjuvant therapy. That being said, I think we tried to use a very personalized technique for our patients.

Some of that will also depend on the exact location of their primary rectal cancer and how close it is to the internal sphincter, and how likely patients are to be able to have low anterior resections versus abdominal paraneo resections. In addition, whether the circumferential margin is involved. Our current approach is really to use a very personalized approach for these patients.

In patients who have high rectal cancers who do not appear to have threatened circumferential margins, we try to lean towards the short course of radiotherapy. But in patients who have low lying rectal cancers, or who have threatened margins, we tend to use a longer course of chemo radiation in the total neoadjuvant therapy setting.

For my debate today, I've been tasked to argue that conventional chemo radiation therapy followed by total mesorectal excision and adjuvant chemotherapy is the correct approach to be using for our rectal cancer patients. I think that this is the correct approach essentially, because we have a long history of randomized clinical trials looking at this with thousands of patients who have shown excellent responses to this approach.

In addition, the studies that seemed to indicate that you can give more chemotherapy when you give it in the preoperative setting, do not seem to show that there is a whole lot of benefit to giving that much more chemotherapy in the preoperative setting.

Essentially, the randomized studies that have been done have shown no difference in terms of survival, no difference in terms of local control or disease-free survival. Essentially, just because patients can get more chemotherapy does not necessarily mean that we should be getting them more chemotherapy. Therefore, I think the conventional chemo radiation therapy approach should still be the approach that we are using in the vast majority of patients.