MD Anderson Cancer Center
Lisa Garvin: Welcome to Cancer Newsline, a podcast series from the University of Texas, M.D. Anderson Cancer Center. Cancer Newsline helps you stay current with the news on cancer research, diagnosis, treatment and prevention, providing the latest information on reducing your family's cancer risk. I'm you host, Lisa Garvin. Today, our subject is using proton therapy to treat liver cancer here at M.D. Anderson. And our guest is Dr. Christopher Crane. He's a professor and the program director of the gastrointestinal radiation oncology program at M.D. Anderson. Welcome Dr. Crane.
Dr. Christopher Crane: Thank you Lisa.
Lisa Garvin: Let's talk about liver cancer in general. It's not a great cancer to have. What are some of the general statistics on liver cancer?
Dr. Christopher Crane: Well, the two major types of solid liver tumors are hepatocellular carcinoma and the other was intrahepatic cholangiocarcinoma. One of them starts from the liver cells, that's hepatocellular carcinoma and the other one starts from the very tiny bile ducts within the liver. The hepatocellular carcinoma is an increasing problem worldwide because of the increasing prevalence of viral hepatitis and alcoholic liver cirrhosis. And because of that, not all patients are good candidates for aggressive surgical resection and the other treatment of choice that--that is used for hepatocellular carcinoma is liver transplant and there're a limited number of transplantable livers that are available at any given time. So proton therapy can potentially control isolated tumors in the liver. The overall outcome really depends on the stage, the underlying liver function in whether or not a tumor can be completely resected or what treatment that they have. So, there's a lot of variables but in general, the overall survival for patients that aren't able to have transplant is very, very poor so maybe 10 to 20 percent 5 years survival.
Lisa Garvin: So Dr. Crane, can you use proton therapy for liver cancer that has metastasized either to the liver or other areas?
Dr. Christopher Crane: Yes. Typically when there's an isolated recurrence in the liver from colon cancer or other--another solid tumor, radiation in particular, proton therapy is a good option to control that and potentially lead to improve survival. So again, like hepatocellular carcinoma, when the tumors are say, over 5 centimeters in size, you can deliver a much greater dose of radiation often in short amount of time that leads to a better probability of tumor cure.
Lisa Garvin: And M.D. Anderson is kind of, one of a very few offering proton therapy for liver cancer at this time in the U.S.?
Dr. Christopher Crane: Correct. Either metastatic of primary liver cancer. Because of the technical challenges, Mass General and M.D. Anderson are really the leaders in proton therapy for liver tumors.
Lisa Garvin: When did proton therapy start being used for liver cancer and did it start here in the U.S.?
Dr. Christopher Crane: Most of the information that is available in the published literature comes from Japan where liver cancer is a greater problem due to the higher prevalence of viral hepatitis. So they have excellent results with high dose proton therapy there in patients who are not candidates for surgery. There was also actually comparable to results with surgery in patients who have more--more morbidities--underlying morbidities.
Lisa Garvin: Before proton therapy became prevalent, what was the next step for people with inoperable liver tumors? Was it the transplant list?
Dr. Christopher Crane: Transplant list is always an option for patients but if they were not candidates for transplant for whatever reason or there was no transplantable liver available, there are palliative therapies including chemoembolization where chemotherapy is embolized through the hepatic artery. Radiofrequency ablation which is an ablative technology, it's good for smaller tumors, and there are some other injectable forms of radiation that are sometimes used but those are usually--those are all typically temporizing measures for patients with smaller liver tumors.
Lisa Garvin: The benefits of proton therapy are many. I mean, you get a more effective dose at the site of the tumor, less invasive type of treatment. How does this fit candidates who cannot be operative on? How is proton therapy a good fit for these patients?
Dr. Christopher Crane: It's a good fit because it's a potential curative option. And if it's not--if it doesn't result in tumor eradication, at least it can take care of the worse problem that the patient has at that particular time which is the largest tumor present. The other challenge that occurs in patients with hepatocellular carcinoma is that it's multifocal so there could be other tumors that developed in the liver aside from that one, that initial tumor. The advantage of proton therapy is that, since it doesn't scatter as much as x-rays, we're able to give a higher dose because the liver can tolerate much--a lot of--a high dose of radiation focally as long as there isn't a lot scattered to other parts of the liver.
Lisa Garvin: Now, can you spare healthy parts of the liver with proton potentially?
Dr. Christopher Crane: Much easier than we can with x-rays because x-rays penetrates throughout--through the body. And if you're gonna give for instance a high dose of radiation to the right side of the liver, it's impossible to do that without causing some damage to the left side of the liver with x-rays. But with protons, you can do that because they don't exit--they don't even go to the left side of the liver, they stay on the right side of the liver.
Lisa Garvin: Now, the chance for recurrence of liver cancer is fairly high, is it not? Does proton have an impact on it?
Dr. Christopher Crane: It doesn't have an impact on whether or not a tumor would recur in another part of the liver. It does--a higher dose would lessen the opportunity--the possibility that the tumor would recur in that local side. In fact, high dose radiation has local control rates of around 90 percent. So the tumor that's being treated is very controllable but it's a multifocal problem so there is a risk that additional tumors will appear in other parts of the liver.
Lisa Garvin: And you said, since the proton therapy center at M.D. Anderson opened in 2006, you've treated about 30 to 40 liver cancer patients. What sort of outcomes have you seen amongst these patients?
Dr. Christopher Crane: Well, we haven't reported our data yet but we've seen a number of patients with complete clinical responses and almost everyone has a dramatic, at least partial response. So we've had--and it's been universally well-tolerated. We haven't really had any significant adverse events. In fact most of the time patients don't have any side effects at all.
Lisa Garvin: So your typical liver cancer patient is male, female, old, young, all across the spectrum?
Dr. Christopher Crane: All across the spectrum. I think the median age is probably 60 years old or so. In there's 60s
Lisa Garvin: And do you see at a lot of lifestyle issues that cause these liver cancers like alcoholism?
Dr. Christopher Crane: In the U.S., the main cause of cirrhosis is alcohol related. And in Asia, the main cause of cirrhosis is viral hepatitis--hepatitis C. So there is a difference there--but there isn't gonna be I think a rising incidence of viral hepatitis in the U.S., you know. It's a worldwide problem. With immigration and things like that, you're gonna see greater rates of--prevalence of hepatitis--viral hepatitis.
Lisa Garvin: Do you find that an increasing number of candidates are illegible for proton therapy or is it still kind of a narrow patient population?
Dr. Christopher Crane: Well, what typically happens is that there--since it's a fairly uncommon disease still, there aren't--there isn't the luxury of having large comparative trials. So there are lot treatments that people advocate for the local regional treatment of hepatocellular carcinoma. And so, what you typically see is that the referrals come, beginning very slowly and then as the clinicians see the effectiveness of the treatment then there tend to be more referrals that come for that treatment. That's what's happening in number of centers, that's what happening in Asia. So, typically what we often do is we have a multidisciplinary approach where we give the chemo embolization for patients and then we consider radiation as a consolidation, proton therapy as consolidation to try to control the tumor at that time.
Lisa Garvin: And your best guess was that perhaps M.D. Anderson is at the forefront of using proton therapy for liver cancer. It's not really widely available at all.
Dr. Christopher Crane: Well, we haven't been--no one has attempted to duplicate the results that have been achieved in Asia which does need to be done. There are couples of centers in Japan that have excellent results with 5 years survival as compared to surgicals--comparable to surgical resection. We are collaborating with Mass General who is also the leading forefront of this treatment with proton therapy on a trial that would--will provide us I think some excellent information about what can be achieved in the U.S. in these disease as well intrahepatic cholangiocarcinoma.
Lisa Garvin: This must be exciting for you as a clinician and a researcher to really kind of--you're kind of like paving the way for standardized proton treatment for liver.
Dr. Christopher Crane: That is a very exciting. As a clinician, I would say to be able to offer something over and above what you're able to offer before with the new tools. So, as I said, there are limitations to--for a large liver tumor. What kind of treatment you can offer them? Typically, it would be palliative if you had only x-rays. And with proton, since you're able to give a higher dose and you offer more hope, and in fact the results are much better based on those studies from Japan. So the exciting thing is really being offer treatment that has a much better chance of resulting in long-term survival for the patient.
Lisa Garvin: And as far the patients, if they were to quiz their primary care doctor or even their primary oncologist about proton therapy, what sort of questions should they ask?
Dr. Christopher Crane: Well, I'm not sure they're gonna get very good answers from a non-specialist about proton therapy for liver--for liver tumors. But, you know, I think that a good question would be, you know, what are the standards treatments, where, you know, should I--who are the best centers to go for this problem for multidisciplinary discussion? One of the advantages of being in M.D. Anderson, one of the greatest advantage is it is a multidisciplinary team approach where the cases are presented in a conference and everyone gives their recommendation. So there's really--the only incentive is to do what's best for the patient. And so I think that patients first and foremost should understand where the best place for them to go is in their region for treatment of hepatocellular carcinoma.
Lisa Garvin: And in closing, obviously the horizons are kind of wide open for proton therapy for liver cancer treatment. Where do you go next? Are you honing your technique and your dosage or what are you--where are you headed?
Dr. Christopher Crane: Well, what we would like to do is further investigate this and expand the utilization of this treatment to more centers. We've been able to collaborate with one other institution but we don't think that the treatment itself needs to be tuned anymore than it is to make an impact. But we think it would be better to open trials that are accessible to more institutions so that more institutions can get experience with this because it is--the technical aspects of it do requires some learning and that is something that we would hope that other centers get more comfort level with because there are technical challenges to do this in an optimal way.
Lisa Garvin: So experience is a must when patients are seeking out proton therapy?
Dr. Christopher Crane: Yeah. There are technical challenges such as controlling or accounting for the motion of the liver with respiration. So when you take a deep breath in, you're liver--your liver moves down and when you let a breath out, the liver moves up. So that either has to be accounted for in the treatment or it has to be controlled by holding your breaths. So we have means of doing that but it does take experience.
Lisa Garvin: Great, thank you very much.
Dr. Christopher Crane: Okay.
Lisa Garvin: If you have questions about anything you've heard today on Cancer Newsline, contact ask M.D. Anderson at 1-877-MDA-6789 [background music] or online at www.mdanderson.org/ask. Thank you for listening to this episode of Cancer Newsline. Tune in for the next podcast in our series.
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