ASCO Guidelines: Adjuvant Therapy for Resected Biliary Tract Cancer

TRANSCRIPT

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Hello and welcome to the ASCO Guidelines Podcast series. My name is Shannon McKernin, and today I'm interviewing Dr. Rachna Shroff from the University of Arizona Cancer Center, lead author on "Adjuvant Therapy for Resected Biliary Tract Cancer: ASCO Clinical Practice Guideline." Thank you for being here today, Dr. Shroff.

Thank you so much for having me.

So what does this guideline recommend?

This is a guideline that is basically looking at the role of post-operative therapy in patients who undergo surgical resection for biliary tract cancers. Biliary tract cancers are a somewhat heterogeneous group of malignancies that include intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma, and gall bladder cancer. And so the question always in most cancers are, if you are able to undergo surgical and curative treatment, is there a role for post-operative chemotherapy or radiation therapy to help improve the chance of cure and decrease the risk of recurrence? So that is exactly what we investigated as an expert panel. So our recommendations are actually twofold. The first one is that we are clearly recommending that patients with resected biliary tract cancer should be offered adjuvant chemotherapy with capecitabine for a total of six months. Within that recommendation, we do acknowledge that this is based on the BILCAP phase III randomized controlled trial and that there was a specific dosing and treatment schedule that was done in that study, but that we are allowing for institutional and regional variances that we've noted in terms of dosing of capecitabine. And so as a result, we're recommending adjuvant capecitabine, and we're allowing practitioners to determine what the best and safest dosing would be, based on their experience. The second recommendation is more specifically for patients with extrahepatic cholangiocarcinoma or gallbladder cancer who undergo resection and have a microscopically positive surgical margin, which is an R1 resection. And in those patients, we are recommending that we could consider offering these patients chemoradiation therapy. Now, again, this is not as strong of a recommendation, because we do not have prospective randomized phase III data to support it. This was based more on a prospective single-arm study out of the Southwest Oncology Group, as well as some other retrospective studies. And so we do go on to qualify that that recommendation should really be made in a shared decision-making approach, with a multidisciplinary conversation to decide the risks and benefits of radiation in these patients-- and that we acknowledge that a prospective study would really help clarify that question a little bit more.

So can you tell us about the research that informed these recommendations?

There have been a number of studies that have looked at the role of adjuvant therapy in biliary cancers. And up until very recently, a lot of these studies were small retrospective series, single-institution or multi-institution, but everything in retrospect-- no prospective or randomized data. And so I think a lot of the reasons that we decided to have these guidelines come out now is that in the last two to three years we do finally have prospective randomized data that helps guide the recommendations. And the majority of the recommendations that we made are based on one randomized phase III, which is BILCAP study. This was a study that was done in the UK and was presented at ASCO in 2018 and is currently in press. And it is basically a randomized controlled trial that compares adjuvant capecitabine by itself versus surveillance alone in patients who undergo surgery for biliary tract cancers. And so our recommendations, which include that study as well as a couple others, is primarily hinged on that, since that is the largest prospective data we have so far. And based on that study, we did in fact recommend that there was a role for adjuvant chemotherapy with capecitabine after complete resection for biliary tract cancers. And based on that research that was done in that trial that was completed, we do believe that the role for capecitabine for six months is pretty strong and that the data supports that now.

So why is this guideline so important, and how will it change practice?

Well, I think it's going to be practice-changing because up until now there has not been a clear consensus on how we approach these patients. And I will say that even now, it's really just this one study that has helped guiding these recommendations. There were a number of other studies that we looked at as part of the expert panel. And these were all prospective studies as well that looked at things like gemcitabine and oxaliplatin in the adjuvant setting, or single-arm phase II studies that came out of the Southwest Oncology Group that also explored the role of radiation. But really, nothing was a positive study other than the BILCAP study. And so up until now, I would say it was a little bit all over the place in terms of how medical oncologists approached resected biliary cancers. I think the majority of us felt that there was probably a role for adjuvant chemotherapy or perhaps chemoradiation. But there was no rules that we could follow, and there was no clear study that we could turn to that would tell us what we should give, how long we should give it for, and whether it should be a combination of chemotherapy or chemoradiation. And so I think it will be practice-changing because now, as part of the expert panel, we are making a very clear recommendation that patients with resected biliary tract cancer should be offered adjuvant capecitabine chemotherapy for a total of six months, hopefully eliminating that kind of regional or specialist-based variation that has been happening up until this point.

And finally, how will these guideline recommendations affect patients?

Again, I think that the main way it's going to affect them is that there's going to be a little bit less gray area, in terms of medical oncologists having conversations with the patients and saying, well, you know, I think that there's probably a role for agent therapy here, but I can't show you the data that supports why I think that. And as a result, I would hope that patients will have a little bit more faith and confidence in knowing that there is a large study that has looked at and proven the benefit of adjuvant capecitabine and that that decreases the chance of recurrence and improves overall survival. The improvement in overall survival was dramatic in this study. And we had not seen a survival of 51 months, which is what we saw in this study, in a very long time. So for patients, not only does it make clear what they should be doing after surgery, but I would hope it also gives them additional hope that we have really changed the bar by doing this adjuvant capecitabine, and that the chance for cure is even higher when we can offer adjuvant chemotherapy. I think the only other thing that may still be a gray area, and that is kind of what we allude to in our second recommendation, and that is in patients who undergo resection and have a microscopically positive margin or an R1 resection. And that's typically patients with extrahepatic cholangiocarcinoma or gall bladder cancer. In those patients, we suggest that they could be offered chemoradiation therapy, but the evidence is not as strong there. Again, it's more retrospective studies that we looked at. There is no prospective study that answers the question of whether or not there's a role for radiation. And so as a result for patients, I think that is still the one area that's a little bit of a gray zone in terms of knowing whether chemoradiation would benefit them if they undergo surgery and have a microscopically positive resection. But I do think that there is a definitive benefit to giving adjuvant chemotherapy, and that, hopefully, will clarify things not only from the physician perspective but also from the patient perspective. Great.

Thank you for your work on these important guidelines, and thank you for your time today, Dr. Shroff.

Thank you.

And thank you to all of our listeners for tuning into the ASCO Guidelines Podcast series. To read the full guideline, go to www.asco.org/gastrointestinal-cancer-guidelines. And if you've enjoyed what you've heard today, please rate and review the podcast and refer this show to a colleague.