Proton Therapy - Fewer Side Effects Treating Childhood Cancers

MD Anderson Cancer Center
Date: 05-31-11


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>> Welcome to Cancer Newsline, a weekly 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 your host, Lisa Garvin. Today, our guest is Anita Mahajan. She is the director of Clinical Pediatric Radiation Oncology at the MD Anderson Proton Therapy Center. Welcome Dr. Mahajan.

>> Thank you very much. I'm delighted to be here.

>> Let's talk about and you focus on pediatric patients. Our Proton Therapy Center has been open since 2006. Well, actually let's back up a little bit. For those who don't know, let's talk about what proton therapy is.

>> So proton therapy is a technology that uses protons to deliver radiotherapy to patients. And the benefit is thought to be a reduction in dose to normal areas that traditional radiation would have delivered radiation to.

>> And I understand, not to get too technical, but apparently standard radiation delivers the--those kind of near the surface of the skin whereas proton tends to penetrate deeper to the tumor, is that correct?

>> It's the right idea but essentially with proton therapy, we're reducing the amount of radiation that's actually going on the other side of the body rather than on the entry side. So for instance, if I'm treating a spine from the back of the patient, there's nothing coming out at the front of the patient. Now, in traditional radiation, some of that radiation actually comes out the front so you can really avoid a lot of normal steps that doesn't require treatment. So, it's nice.

>> And since 2006 when our Proton Therapy Center came into being, a lot of proton therapy centers come up. There's a lot of talk about proton therapy. To the lay person why is it so different than standard radiation therapy, what's the deal in other words?

>> I think the biggest opportunity we have is to reduce side effects. And to reduce side effects either during radiation and definitely in children, we think it's gonna reduce side effects down the road as they age and mature. So we think it's an exciting technology to give a better quality of life to our patients as they get older especially the children. The additional thing is we might be able to get more dose into a patient that requires a higher dose of radiation. So, sometimes we're limited by the normal structures. And with proton therapy, we might be able to get extra dose and that might be beneficial to the patient also.

>> How many pediatric patients have you treated at the Proton Therapy Center so far?

>> The last count was over 350.

>> What range of diseases are you treating?

>> Our main disease type has been brain tumors in children just because that's the most common type of tumor in children that requires radiotherapy. But we have treated sarcoma, Ewing sarcoma for instance, rhabdomyosarcoma sarcoma. We've treated a few patients with neuroblastoma so a wide variety.

>> Long-term side effects are a big issue with pediatric cancer patients and there are certain treatments, I guess, that can cause these long-term effects. What sort of long-term effects can children see from standard cancer treatments? So that's a great question and there have been a lot of efforts between different institutions and internationally looking at the late effects that children experience after they've been treated for cancer. A lot of our patients, we realized are living a long time after their cancer treatment. They're surviving their disease. And we've noticed that their side effects can impact their quality of life, their education level, their hormones that is their growth, the function of the normal structures. So, what we're hoping is with looking at all of our therapies including chemotherapy, surgery and radiation that we're gonna provide them an opportunity to have fewer side effects. Now, from the radiotherapy point of view, there have been a lot of side effects associated with radiation, growth development, neurocognitive function, educational function, their ability to integrate into society as an independent individual. A lot of these things have been affected by radiotherapy. And we find that in children when they're treated at a younger age to large parts of their body. All of these areas and domains can be affected. So with proton therapy, we're thinking that if we can really reduce unnecessary radiation to the child, that's gonna help them benefit them in the long run. Additionally, we've changed our technologies. We're a lot more careful about who we treat, how we treat them. We use a lot of different approaches. For instance in Hodgkin's disease, we're reducing the amount of radiation we're giving to reduce the possible side effects which includes secondary tumors. And in children, very, very young children, we try to avoid radiation for as long as possible. So our approach is really to develop and change over the last several decades because we realize our kids are suffering from the treatments that help them survive.

>> Has there been a critical mass of data to show that proton therapy is improving long term quality of life in children yet?

>> Not yet. And that's one of our efforts within our own institution but we are actually collaborating with other big institutions that have proton therapy to try and sort out these particular questions.

>> Let's talk about pencil beam. That's a particular type of proton therapy that's even more focused. Can we talk about pencil beam and are you using pencil beam on children?

>> We've started using pencil beam on children and we think it's an exciting technology. It's a very challenging technology to really fine tune. And we're in the process of developing it and modifying it to soothe the needs for children. One of the challenges is that our children are small. And for the pencil beam technique, the tumors have to be at certain depth. And a lot of our children, the tumors are quite superficial. But with our physics and engineering teams, we're modifying our approach and hopefully we'll be able to employ it more consistently in our very young children.

>> Are there any trends you're seeing in treatment? Have you been able to kind of hone the treatment a little bit over this past few years and maybe discovered things that maybe you are able to tweak a little bit?

>> Absolutely. I mean, we're constantly looking at the way we do things and constantly refining so I think we're getting better and better.

>> How do the patients themselves, I've seen some of them on the website, they're quite young, many of your patients. How do they react to all of this? Is it less scary to them, is it kind of cool, or how do they react to the treatment?

>> It really varies, you know. I think that every child comes with his own particular history, his own family environment. But most of the time, we try to make the child comfortable within the environment. There is a certain routine that we develop and that actually makes them feel more comfortable. Nobody approaches them with big needles. And they actually participate in their treatment as much as possible that it kind of does become a little bit more fun. And we have child life experts that help them through the process. And we actually involve the family in it also to allow them to become more comfortable with the process too.

>> Do you find that patients are actually or the parents of pediatric patients are seeking out proton therapy? Are they being more proactive about it or is it something that's kind of decided after they are diagnosed?

>> I think it's a 50, 50 thing but there are certainly instances where the families have sought out proton therapy because they've heard about it, read about it and realized that maybe this is a better opportunity for their child in the long run. But within the medical community amongst the pediatric oncologist, there is recognition that this may be a good way to proceed.

>> And does proton therapy just substitute for traditional radiation therapy or can it be a substitute treatment for surgery and/or chemotherapy?

>> We currently and will always have a multidisciplinary approach and that it is very, very important to have an expert opinion from the surgeons, the chemotherapy physicians, as well as ourselves to try and come up with the best possible approach for that individual patient. Most of the time, it incorporate surgery, chemotherapy and radiation. Sometimes where surgery is not possible, radiotherapy is the means to develop a local control approach. But it's certainly not a substitute all of the time but sometimes it can be an alternative.

>> Is there the possibility that other pediatric diseases would be a candidate for proton therapy in the future?

>> By other pediatric diseases, nonmalignant diseases or--

>> Or other types of cancer.

>> Yes, possibly. There have been some preliminary evaluations of the treatment of Hodgkin's disease for instance. And that is something that a lot of centers are exploring. Right now, there has been one institution that's looked into in a more robust fashion. And we've done a few cases but in the future, that maybe an option. Neuroblastoma is something that we're getting a little bit more experience with and it's not a common indication but it may be in the future.

>> So Dr. Mahajan, I guess pediatric patients do have to be anesthetized for proton therapy?

>> Correct. The younger children who aren't able to lay still for half an hour to 45 minutes, they do require sedation. We're lucky enough to have fantastic anesthesia team that has been very, very supportive from the beginning.

>> And we use sedation and it's not general anesthetic. And it's tolerated really, really well and a lot of our kids enjoy it, a little too much sometimes I think. But they're very, very good and they are very flexible with our needs and our patient's needs. And we are able to incorporate chemotherapy during the radiation and patient stays, and they have been very accommodating. So, that's what they call contra sedation where they're kind of semi aware of their surroundings as opposed to general anesthesia where you're totally out cold.

>> Correct. They're breathing on their own, their heart is going on their own, they are supported and they are--and they're observed and monitored during the whole process. And they--but it is not full general anesthetic.

>> Is that something that MD Anderson is kind of unique and that we're making in roads or making innovations with pediatric anesthesia?

>> Our pedia anesthesia teams have been really great and they're very supportive. They're using propofol. A lot of other pediatric facilities are actually using propofol but there are some facilities that use a little bit more of an invasive technique using an oral airway for instance. But we don't find that necessary.

>> Are parents worried when their child is put on sedation? Do they feel like--are they allowed in the treatment area with their children?

>> It's really important to us that the family is comfortable and that the child is comfortable going into the room. So the parent usually escorts the child in or brings the child in and actually holds the child while they are going to sleep. So the family feels comfortable. The child feels comfortable and usually, there is less stress and anxiety overall so things go smoother. When the child wakes up, the parents are around. So they again feel very secure in their environment. And as I mentioned before, they are part of the process so they are allowed to use, press certain buttons that allow them to have a sense of control over what's going on.

>> We talked earlier about data we've been collecting to learn more about the efficacy of proton therapy. But have you been able to craft like followup recommendations for proton therapy pediatric patients, like should they come back like every 6 months or is there kind of a long term followup program that's been created?

>> That's actually a great question because it does address an issue that we're challenged with amongst pediatric community at large. And there are long-term survival guidelines and care guidelines that are available on the internet and the websites, the Children's Oncology Group. And there are actually guidelines for family doctors to follow about any childhood cancer survivor. But within the proton community, we do have a huge effort to try and get data on patients so that we can actually really robustly look at what's going on on this population, and to gain evidence and collect evidence that supports the role of proton therapy in this population. So we do request that patients come back to us. We are looking at them holistically, looking at their growth and the development and their ability to integrate into normal schools, looking at their tumor status, looking at the late effects in general. So yes, we do like for our patients to come back to us so that we can study and collect data.

>> Now, if parents who have children that have just been diagnosed with cancer and they are considering proton therapy, what sorts of steps should they go through, what should they learn, where should they go, what questions should they ask?

>> Well, I think the first thing they need to do is to get to a big cancer hospital that specializes in pediatric patients. They need to ask good questions locally, we're not the only center in the world and we're good. But I mean, I think, they really need to explore what's available locally. And when it comes to the radiation questions, ask the questions that they have in their mind. Be open about what questions and concerns they have regarding their own child. What are the options they've heard about and post them to their local physicians. We have websites, we have the MD Anderson website that actually explains a lot of information. We have contact numbers and so if they do want to explore the options we may have here, they should contact us.

>> And are there support groups? I do believe we have one here at MD Anderson but I wonder if there are support groups for parents of children who are going through proton therapy. Or maybe it's just the adults, I don't know. But I think there is a--

>> There is. Actually, there's a grassroots effort through some patients themselves. A lot of patients have actually volunteered themselves as being contact people to be helpful to other new patients and families. But there is no specific website or effort that I'm aware of for--that is set up more formally.

>> Are there any sort of research avenues that you're going down in regards to proton therapy for pediatric treatment?

>> The nice things is, is that we are allowed to use proton therapy on the most national protocols that are ongoing through the Children's Oncology Group, the Pediatric Brain Tumor Consortium. So, there is a recognition amongst the national groups that proton therapy is here and that we're gonna be using it and it is a good option for most of our children. Within our own community, we actually have specific protocols for retinoblastoma. We are actually in the process of developing more concrete followup for neurocognitive data. We are looking at variety of different approaches of delivery of radiotherapy. And I think our efforts will continue to grow.

>> Great, thank you very much.

>> Thank you.

>> If you have questions about anything you've heard today, on Cancer Newsline, contact askMDAnderson at 1-877-MDA-6789 or online at Thank you for listening to this episode of Cancer Newsline, tune in next week for the next podcast in our series.

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