Preventing Pitfalls in Y-90 Treatment

dan brownTreatment with yttrium 90 (Y90) is an integral part of the practice of interventional oncology. Practitioners experienced with these procedures, as well as those entering the field, must navigate the decision of when to recommend treatment and how to ensure the procedure is carried out safely and effectively. In this interview with Interventional Oncology 360, Daniel Brown, MD, chief of interventional oncology at Vanderbilt University, offers his advice on the particulars of Y90 treatment. Dr. Brown will be a faculty member at the 2018 Symposium on Clinical Interventional Oncology (CIO) on February 3-4, 2018 in Hollywood, Florida.

Y90 is an exciting treatment option, but it’s not always appropriate. When is it not a good idea to treat with Y90?

I’m going to focus on metastatic disease in answering this, but the whole decision tree about when to treat somebody is based on how much liver do you need to treat, the liver function, and the patient’s performance status. If you have a patient with a small focal HCC and a bilirubin of 2 or even 3, that you can get to very peripherally in the liver, those patients can be treated safely.

When we see patients with metastatic disease, they almost invariably have at least one side of the liver significantly involved, and both sides of the liver usually need to be treated. If those patients have elevated bilirubin at all, they are really at high risk of decompensation from treatment. When I see a patient with metastatic disease and a bilirubin of 1.5, I’m much more concerned about adverse outcomes than I am with an HCC patient with the same bilirubin. People with HCC often have underlying cirrhosis, and they often tolerate more aggressive therapy than metastatic patients without cirrhosis who have even mild elevations in bilirubin. The risk is consistent for both Y90 and other arterial therapies.

Do you have any advice to practitioners performing Y-90 procedures? What are some possible problems to avoid?

I think it’s important to be diligent throughout the mapping procedure, and I continuously remind my fellows and myself that this is the most important step. The mapping study is where I try to identify as many pitfalls as possible. At the end of that study, we need to know exactly where we’re going to put the catheter for all infusions.

During the mapping study, I plan every bit of the procedure, from the catheter placement to the type of base and microcatheter. Can I use 0.028” (my preference) or will a 0.024” be required? Are there arteries that need to be embolized? If there are, they are treated at mapping. I want the day of treatment focused specifically on getting the catheter to the correct spot, delivering the dose, and making sure nothing is happening with the connections or the infusion.

At infusion, the opportunity of a problem due to distraction is greatest when you’re setting up the box. This risk can be amplified in a teaching institution, when operators are teaching fellows how to do the procedure and set up the infusion set.

What are some of the concerns that could potentially be distracting during treatment if not handled at mapping?

I worry about a vessel with an odd course that I may have missed at mapping. Do I need to select and/or embolize it? When this is taken care of during mapping, the focus on the day of treatment is on simply getting the catheter to the correct place. The treatment becomes much more stressful if these concerns are not handled during mapping. You may set yourself up for failure if you don’t account for everything at mapping. C-arm CT at mapping is very useful to answer these questions.

Do you have a strategy for accounting for everything possible during mapping?

Any time the left lobe is being treated, we need to know where the right gastric artery is located. My suspicion is that this vessel is usually the culprit in ulcer formation following treatment. If the right gastric isn’t obvious, we will do a left gastric artery injection to try and identify the “circuit” where it communicates with the right gastric artery.  Also, for tumors in the watershed zone of segments 4/5/8, or for large tumors, c-arm CT is crucial to ensure complete tumor coverage is obtained.

Does your advice differ at all for practitioners experienced with the procedure vs those who are new to it?

I think the advice about mapping is universal. For people new to Y90 procedures, it’s important to ensure that referring physicians know that the imaging response to Y90 on imaging takes longer than that of other arterial therapies. Communicating this with other physicians can limit stress for referring doctors expecting the potentially more rapid response seen from embolization or chemoembolization. You don’t necessarily get that type of response with Y90. You might assess people at the first imaging study and not see much improvement, but if you wait 3 months there is usually improvement.

Navigating the short interval follow-up period can be tricky, depending on the intensity of the situation. In my practice, we tailor management to the individual patient’s therapeutic plan. For example, if someone is in the transplant pathway, they may lose the opportunity for a transplant if the tumor doesn’t respond well or progresses. We tend to use more chemoembolization in that setting because we don’t want to automatically assume that the patient’s imaging response will improve at the next scan. If you make that assumption and are wrong, that patient has lost an opportunity for cure. It’s also true that those patients may be responding perfectly well to the Y90, but they are in a very narrow window regarding tumor size.

As a result, our group usually performs chemoembolization for patients under consideration for transplantation. We’ve had really good responses, and the transplant surgeons have been happy. That being said, if someone is not transplantable, they are very happy for us to use Y90,  as the quality of life is better maintained with radioembolization.

Does the way IO is practiced vary in different areas?

I think there’s a lot of variability in practices around the country, and even more so in the US compared to other countries. Y90 is more commonly performed in the US than in most other places in the world. To the best of my understanding, Y90 is less easily available in many other countries.

Is the combination of immunotherapy and interventional oncology promising?

I’m excited about the possibility of incorporating IO with systemic chemotherapies and biologic therapies, which now include immune therapies. Incorporating immune therapy with Y90 is going to be a key component of finding other avenues of success. We can’t presume to know where such combinations may work best. We’re still trying to figure out where immune therapy works well outside of areas such a melanoma and some of the well-established pathways. On the RESIN registry, we are tracking people who have received immune therapy. I’m optimistic that the registry data will identify potential tumors that would benefit from combining Y90 with immuno-, chemo-, or biologic therapies.