Glass Microspheres for Colorectal Metastases to the Liver: An Interview With Ryan Hickey, MD, and Robert Lewandowski, MD

At the 2015 Annual Scientific Meeting of the Society of Interventional Radiology (SIR), Ryan Hickey, MD, and Robert Lewandowski, MD, interventional radiologists from Northwestern University in Chicago, presented data on outcomes of glass microsphere therapy for metastatic colon cancer to the liver. Interventional Oncology 360 asked Drs. Hickey and Lewandowski to share some details from their presentation and to talk about the status of research in interventional oncology.

IO360: Could you describe the multicenter study of glass microspheres?

Hickey: We performed a study combining data coming from multiple centers around the country looking at survival outcomes as well as safety and toxicity of using glass microspheres to treat patients with colon cancer liver metastases. The majority of published literature to date has focused on resin microspheres, likely related to the FDA approval of resin microspheres for hepatic metastases from colon cancer in conjunction with a surgically placed hepatic pump/fluorodeoxyuridine. However, there is significant use of glass microspheres to treat metastatic colon cancer, and we sought to evaluate their efficacy, safety and toxicities.  We collaborated with 7 other institutions around the United States to compile data on over 500 patients who were treated over a period of more than 10 years. We analyzed that data and had very interesting and very consistent outcomes in terms of survival, in addition to very low incidences of toxicity and adverse events.

IO360: Can you describe some of the more remarkable results?

Hickey: One of the most interesting things is that the survival data is very consistent with other studies of radioembolization in the treatment of colorectal liver metastases, whether glass or resin microspheres were used. The median overall survival for our patient cohort of 531 patients was 10.6 months. This number is nearly identical to survival outcomes that have been reported in other large studies, including one of the largest trials published to date by Dr. Lewandowski that analyzed outcomes of more than 200 patients with colorectal liver metastases treated with glass microspheres. 

Lewandowski: Those results were presented last year at SIR and were published this past year. This current study highlights the benefit of doing registry-type studies. It is extremely difficult to perform prospective, randomized trials on therapies used in the salvage setting, particularly in a disease such as colorectal carcinoma for which therapies are continuously and rapidly changing. As far as cancer treatment registries are concerned, this is a smaller registry trial with just over 500 patients. But for our specialty, a registry of this size is quite large. The Society of Interventional Radiology is currently working to create structured and standardized reporting in order to facilitate collaboration and registry trials among SIR members. With the appropriate resources and support, very interesting data sets can be accumulated that will help to support the treatments that interventional radiologists provide, not only in oncology, but in other areas of interventional radiology as well. This can help to bring our specialty further into the “mainstream” of treatments and to establish a place in consensus treatment guidelines. 

IO360: What do you think the results of this study could mean for glass microsphere therapy in the future?

Hickey: For glass microspheres in particular, I think the results of this study support exactly what those of us who have been treating colorectal metastases with glass microspheres have experienced in our practices, which is that the survival outcomes are very consistent with those that have previously reported with resin microspheres and that the treatment is safe, very well tolerated, with a very low incidence of toxicities.  But most importantly, this study further validates the use of radioembolization in the treatment of colorectal liver metastases, whether the interventional radiologist chooses to use glass or resin microspheres. We’ve now added to a growing body of literature that shows significant benefits for patients with a disease that has essentially stopped responding to chemotherapeutic and biologic agents, and it really shows that there is promise for a treatment that may end up extending their overall survival. Obviously that needs to be evaluated in a comparative study, but it does point to the fact that we have a very valuable tool in our armamentarium that should arguably be used more.

Lewandowski: We hope to use data like these to further define the role of radioembolization in cancer treatment guidelines such as the National Comprehensive Cancer Network guidelines. While these data are currently acknowledged, they certainly don’t have the highest level of regard.  As I mentioned before, it will be very difficult to obtain randomized data in the salvage setting, but in order to gain recognition in the medical oncology world, we need, at a minimum, larger data sets. We also need to make sure that we are sharing our results—either in the form of publications or presentation—with medical oncologists.  

It is also very important to mention here that both Sirtex and BTG have been very supportive in evaluating the role of radioembolization in first-line or second-line treatment. They are conducting randomized, prospective studies looking at the use of radioembolization with chemotherapies including trials evaluating resin microsphere radioembolization as part of first line treatment of colorectal liver metastases (data presented in May) and glass microsphere radioembolization as part of second line treatment of colorectal liver metastases. Most of us who do these therapies feel that there is a role for them and we’d like to see more acknowledgement of that role. There’s a lot of excitement now about the amount of industry support and trial sponsorship we are getting. We certainly require their support to get these data.

IO360: Any other studies that are in the works that you think you’d like to point out?

Lewandowski: From a radioembolization standpoint, there are other studies, but not in colorectal cancer. Both BTG and SIRTEX have studies currently enrolling for patients with advanced stage hepatocellular carcinoma.  These studies offer radioembolization in combination with or compared to sorafenib biologic therapy, which is often considered current standard of care for these patients. Again both companies are to be applauded and supported in the way that they are doing these studies and getting the data that we need to be successful. 

IO360: And the data is what’s going to convince the world and other medical specialties that this can be another pillar of cancer care.

Lewandowski: Correct. The oncology world is very heavily data driven, which is different from some of the other arms of medicine, which may be a little bit more anecdotal. They’re very guideline driven and really want to see data. We need to provide that data. 

IO360: Anything else you wanted to add for IO clinicians about this study or research in general for interventional oncology?

Hickey: I think this study highlights the importance and the value of collaborative efforts. By working together, with large and small cancer centers around the country, we can really improve the quality and the amount of data that we have for our treatments and procedures. It is really the data that are going to bring our specialty forward.

Suggested citation: Ford J. Glass microspheres for colorectal metastases to the liver: an interview with Ryan Hickey, MD, and Robert Lewandowski, MD. Intervent Oncol 360. 2015;3(8):E98-E100.