Selective Internal Radiation Therapy in Colorectal Cancer

Transcript:John Marshall, MD: Whenever I’m irradiating anything in GI, I throw a little 5-FU in. Who’s with me on this?

Alan P. Venook, MD: Well, you throw capecitabine in.

John Marshall, MD: I throw capecitabine, yes.

Alan P. Venook, MD: We have a study, for example, with TAS-102 using that as a radiosensitizer. I think as a general principle, it’s true that chemotherapy, especially the fluoropyrimidines, will amplify the effects of radiation. We see that as well with any of the fluoropyrimidines, so we tend to do the same.

John Marshall, MD: I’ve heard a bunch of different data points on this, but I think the common thing is about 2 to 3 weeks of radiation being delivered. So, you give the shot and there is some radiation dose being delivered. I want some drug on board. I would even argue in patients who were refractory or progressing, I’d throw a little in just like if I were radiating an esophagus or a rectum. Agreed?

Johanna Bendell, MD: I don’t tend to do it during, or have like a pump running while they’re getting the Y-90, but I do take it up to maybe a week before the Y-90 and then you can restart it afterwards.

John Marshall, MD: And you can restart it afterwards. I do think there’s the other push that I’ve heard the IR people know about bevacizumab, and their belief. I think there is some evidence to suggest that if you’ve given bevacizumab recently, then the vascular supply isn’t adequate. They get less delivery to where you want to go. At least my IR guys and gals want me to be a few weeks out from bevacizumab. Everybody the same there? So, in a frontline setting?

Tanios Bekaii-Saab, MD: Yes, in a frontline setting. If you only use it as a maintenance strategy, you have to give them a break from the bevacizumab for 6 to 8 weeks.

John Marshall, MD: Okay. So, chemotherapy is safe during to give, the best we can tell. You’ve got to watch your bevacizumab; multistep process, pick your patient. There’s one other thing I am concerned about: toxicity issues. I know Alan and I have talked about this before. In giving liver-directed therapy earlier, if I got a few years to go, what’s that liver going to be like? And we all experience that pseudo-cirrhosis, this hypersplenism. How are you dealing with that thinking? Is that shifting your decision-making, Johanna, about when to do this?

Johanna Bendell, MD: In all honesty, it makes me a little bit more nervous to do it up front because those patients generally have a long journey ahead of them. Now, for specific patients, as we were referring to earlier, who have got that bulky disease where you really need some tumor shrinkage, they’re not as responsive to the chemotherapy, I don’t hesitate using that earlier. But, sometimes it gives me a little pause to say that if I’m using it straight up—not having all the long-term data read out from the first-line studies, which we do need to make that decision correctly—I tend to push it off a little bit more.

John Marshall, MD: OK. So, it’s here to stay it looks like?

Alan P. Venook, MD: I think so. There may be a better widget out there coming along, but I think the modality, definitely, is effective, and we just have to figure out where the right niche is.

John Marshall, MD: And it’s a little bit off topic, but it’s pretty effective in colorectal, HCC, right? And I think in neuroendocrine…

Johanna Bendell, MD: Neuroendocrine tumors.

John Marshall, MD: But, we’re seeing this now in cholangiocarcinomas and breast cancer and other places where liver-dominant disease rises. Is that happening at all of our centers?

Tanios Bekaii-Saab, MD: It is. I’m not sure there is, or there should be, much support to it. I’ve not had really good luck with cholangiocarcinoma and this modality, to be frank. I think I’ve seen it used in pancreas cancer, in some patients, and I think that’s really going outside what would be considered acceptable.

John Marshall, MD: It has to be the right patient.

Tanios Bekaii-Saab, MD: It has to be the right patient, and you really have to pick those patients. And, as all of you were saying, if you do, you see really good results with this modality.

John Marshall, MD: And so, the last point on this is it’s not necessarily either/or on liver resection. We tend to think of it in the unresectable patient, but safe to operate after?

Alan P. Venook, MD: So, that’s a good question. We don’t have a large experience. The handful of patients we’ve done in that sequence, we’ve not had a problem. But, I don’t know more broadly. I think that’s something to look at. Again, as you alluded to, earlier use, you do have to worry about cirrhosis down the road. We learned with embolization, for example, of carcinoid patients that 5, 6, or 10 years later, a number of them went on to develop cirrhosis from biliary strictures or from ischemia. We shouldn’t rush to be using this, it could be overwhelming, but I think certainly with judicious use, it’s the right thing to do for patients.

John Marshall, MD: Real need for multidisciplinary input. Just like we’re thinking resection, we’re thinking for our IR team that this is out there. Not every IR guy/gal has this or is up to speed on this, so that does affect referral patterns. So, we know that’s a barrier out there in the community.

Transcript Edited for Clarity