Using SBRT to Treat Colon Cancer

Podcast Transcript

Dr. Scott Steele: Butts and Guts, a Cleveland Clinic podcast exploring your digestive and surgical health from end to end.

Dr. Scott Steele: Hi again, everyone, and welcome to another episode of Butts and Guts. I'm your host, Scott Steele, the chair of colorectal surgery here at the Cleveland Clinic in beautiful Cleveland, Ohio. And today I'm very pleased to have Dr. Ehsan Balagamwala who's a radiation oncologist. He's also the co-director of our colorectal cancer center program here at the clinic in the Department of Radiation Oncology here in our institute. So, Ehsan, welcome.

Dr. Ehsan Balagamwala: Thank you so much, Scott. Good to be here.

Dr. Scott Steele: So today we're going to talk about something that is just been wonderful for you to have, and that's having and using SBRT to treat colon cancer and specifically colorectal cancer. And before we dive into that, tell us a little bit about yourself, where you're from, where'd you train, and how did it come to the point that you're here at the Cleveland Clinic?

Dr. Ehsan Balagamwala: Absolutely. So, I grew up a little bit all over the place, some in South Florida, some in Missouri, and I did undergrad in upstate New York. And when I was applying to medical school, I by chance applied to Cleveland Clinic, which was a very young medical school at the time. The moment I set foot on the campus, I was like, this is where I want to be. And so, I was lucky enough to get into medical school here and I have not left since. I trained here and I'm lucky to be on faculty here.

Dr. Scott Steele: So today we're going to talk about SBRT, and obviously you and I see a lot of patients together and I'm very grateful for your skill and expertise, but let's start at the 10,000-foot view level. Tell us a little bit about stereotactic body radiation therapy and why colorectal cancer and give us a little bit of background into this.

Dr. Ehsan Balagamwala: Absolutely. So stereotactic body radiotherapy or SBRT has been around for about 10 to 15 years. The concept of doing fewer treatments in radiation really started in the 1960s and 1970s with gamma knife radiosurgery for brain metastases. And as technology has gotten better, we're able to translate that convenience and of course the biological advantages, and we'll talk more about that to the rest of the body. One of my passions is kind of utilizing these novel treatment techniques and applying it in scenarios where we wouldn't normally think about applying. And colon and rectal cancer is chiefly among them because with the lymph nodal drainage of colon cancer, typically radiation has not been utilized with the advantages of surgery and chemotherapy that's been kind of the cornerstone for colon cancer. However, the better the systemic therapy gets, we're seeing more and more patients with recurrent cancers and that's where radiation can really help our surgeons operate and do an even better job.

Dr. Scott Steele: So, staying at a high level, how does radiation work in terms of having its role in treating cancers in general? We've had Dr. Amarnath talk about just traditional radiation oncology. We'll talk about the differences here in a minute. And we've also talked about intraoperative radiation therapy for which you and I do cases for together. And so, how does radiation therapy work and then specifically what is that difference that we're talking about SBRT with conventional radiation therapy?

Dr. Ehsan Balagamwala: So classically, when we think about conventional radiation, the radiation that's delivered over the course of four to six weeks with daily treatments. What radiation is doing is doing DNA damage on a daily basis. And the reason why we must do it over time is because there's a difference in the ability of normal tissues to repair themselves versus tumors. So, cancer cells are sick inside and they cannot repair DNA damage whereas normal cells can. And so, we leverage that difference, give small doses of radiation over time where the normal tissue recovers whereas the cancer can't, and it dies. And when we combine that with chemotherapy for conventional chemoradiation, we can cure many patients as a result. SBRT turns that whole concept on its head because it's doing treatments in either one or up to five treatments and delivering very high doses of radiation that we previously thought that the normal tissue couldn't handle. But with modern technology, we can actually deliver that radiation not only effectively but also extremely safely. And what we're learning over the last, especially five years, is that the biology of how cancer cells die with SBRT is very different. And that is what the biggest advantage of SBRT is. Instead of slowly killing cancer, it ablates it. You can think of it as kind of freezing, kind of like cryotherapy, just ablates that cancer, and it's the vascular damage on top of the DNA damage that's happening that leads to that effect.

Dr. Scott Steele: So, you mentioned earlier that obviously radiation doesn't play as big of a role in colon cancer, it does in locally advanced rectal cancer. But who qualifies for SBRT as a treatment option for colon cancer?

Dr. Ehsan Balagamwala: So, as I mentioned, it's mostly in the recurrent setting. There are three groups that I think about. One is in the metastatic setting where the cancer has spread to either the lung, the liver, a bone, and it's not operable and we want to use a non-invasive ablative technique. The other option is in the inoperable setting because of local extension, we cannot operate on that patient. And the one that we've been working a lot on recently is in those patients that are actually technically operable, but we want a little bit of down staging to get an R0 or a negative margin resection. And I think that's where I think the novelty of this is really going, is in the last 10 years SBRT has really been used in the non-operative setting where we don't want to operate on someone. But I think there's a huge advantage, we know from many decades of research, that a negative margin resection is much better than having a little bit of cancer left behind despite the best efforts. And so doing SBRT allows us to oblate that margin and get a really good resection and possibly add intraoperative radiation during the operation to really ensure that once we take that recurrence out, we're not going to have a recurrence right there.

Dr. Scott Steele: So, truth or myth: SBRT can be used to treat other cancers: lung cancer, prostate cancer, or liver cancer?

Dr. Ehsan Balagamwala: Truth. The way SBRT was actually translated into the rest of the body from the brain was actually to treat primary lung cancer. That was one of the early indications in those patients who cannot get an operation or lobectomy for their early-stage lung cancer because their lungs were not healthy enough. And so, with SBRT we were able to cure a large proportion of those patients without the need for an operation. And so, since then it's been used for curative treatment for prostate cancer. We can treat liver metastases, primary liver cancers, adrenal cancers. Now there's a movement on treating renal cell carcinoma, as well as one of the most novel things that has started in the last two or three years is to use SBRT to treat ventricular tachycardia, which is not a cancerous situation at all.

Dr. Scott Steele: Okay. Now, so I'm a patient out there and their doc said, you're getting SBRT. So, walk me through this whole thing. What can the patient expect before receiving SBRT? What actually happens? Are you strapping me down as a patient or how can you hit that spot when I'm breathing? And then, what's the recovery time following this treatment?

Dr. Ehsan Balagamwala: Absolutely. So, the first step is to meet with each of our patients and talk them through everything. And the very first step before we start radiation is something called simulation. The simulation is when we bring the patient back, create a mold around their body so that their body can be still during treatment. We are looking at the accuracy on the order of one to three millimeters. So, we want very accurate treatments. We create that mold that fits the patient like a glove would fit a hand. Depending on the location, if it's in the pelvis I don't use any breath control device, but if it's in the lung, we use breathing control devices to minimize motion. Once that is done, we do a very fancy CT scan. Once that is done, the laser is localized on the patient where the lesion is and we put little, tiny tattoo dots, and then the patient goes home.

It takes about a week or 10 days for us to come up with a treatment plan. And once we have a treatment plan, we bring the patient back into our treatment room, which is size of probably a small ballroom. We use that same body mold that we created for them. They lay on that comfortably with their arms above their head with exactly the same setup that we had at the time of simulation. And the S part of SBRT is called stereotaxis and that really means using advanced imaging to localize the cancer. And so, once they're set up in the treatment position that we had intended to, we actually do a CT scan around the patient utilizing those lasers to localize that. And once we have that CT scan, we co-register or put it on top of the original CT scan. And if there's any differences in position, the couch that the patient is lying on a robotic couch. It moves in six different dimensions, so right, left, up, down, but also rotates around those axes and gets them within my target is always a millimeter or less.

And once we have that position, the treatment starts. The actual treatment delivery time is on the order of one to two minutes, really, on a daily basis. If it's a single treatment only, then the treatment can be about three minutes. You don't feel anything; it's like getting an x-ray done, the radiation just goes through and through and then you are done with the treatment, you get back up and you walk home.

Dr. Scott Steele: So, I've got to ask you then, are there any side effects to SBRT?

Dr. Ehsan Balagamwala: Certainly, just like with any treatment there can be side effects and it's mostly dependent on the location. So, if there's bowel nearby, some patients can get a little bit of nausea. Ulcers can develop in the long run. If it's in the lung patients can get a little bit of mild pneumonia that we can treat with steroids if that happens. The risk is low, 10 percent or less, but things can happen. But with advanced treatment planning we have found even if there's bowel nearby, we can deliver radiation very safely and keep the severe risks less than 5 percent.

Dr. Scott Steele: So, let's look at it the opposite way now. So, when is SBRT not an appropriate treatment for a patient?

Dr. Ehsan Balagamwala: That's a fantastic question, and it's a very hard question to answer, but I'll try my best. The biggest contraindication I see is if you cannot see the lesion on a CT scan. So, if I cannot see it, I cannot line it up appropriately, and so then I cannot deliver a very high dose accurately. And so, if I don't see the lesion, the patient is not eligible. So, for microscopic disease, for instance in the post-operative setting, SBRT is much tougher, if not impossible, to do. The other situation that I see somewhat frequently as a GI radiation oncologist is if the tumor is invading into a loop of bowel. So, for a pancreas tumor, if it's invading at the duodenum or a recurrent colon cancer invading into the small bowel or large bowel, our biggest worry is that if we treat it with SBRT, we might have a great response leaving a hole and an emergent situation. So, if there is luminal bowel invasion, then we try not to do SBRT.

Dr. Scott Steele: Completely makes sense. So, are there any advancements on the horizon when it comes to using SBRT to treat colon cancer?

Dr. Ehsan Balagamwala: I think there’s a lot of excitement in this setting, and we've been working on some together, I think SBRT has been underutilized in the preoperative setting, which is where I think we're making the biggest difference right now, because I do believe that by itself SBRT can sometimes not have as optimal of a local control, especially in the abdomen. And when you add it in addition to surgery, we can really enhance the local control and get it up to 95 plus percent and reduce positive margin.

Dr. Scott Steele: Yeah, it's been anecdotally wonderful to be able to kind of pair together as we continue to have patients just like this and get them, that really our goal is to get all the cancer out and make sure there's no microscopic disease there. And there's some tricky situations in the body where that additional therapy up upfront prior to me going in as a surgeon has been extremely valuable and fun to watch.

So now it's time to get to know you a little bit better. So, it's time for our quick hitter. So, go ahead and tell me what your favorite food is.

Dr. Ehsan Balagamwala: Ooh, I love eating. So being South Asian and eating my mom's home-cooked food and eating all over the world, I think one of my favorite foods is something called biryani which is an Indian and Pakistani dish with rice and usually chicken or meat. There was an article on BBC at one point, there's probably like 40 different recipes for this, and the best way to describe it is just a dance in your mouth.

Dr. Scott Steele: So, I have to ask you, can you order it out here in Northeast Ohio?

Dr. Ehsan Balagamwala: You can, I haven't found a great place outside, but next time my mom's in town, we'll bring you some.

Dr. Scott Steele: Fantastic. And so, what's your favorite sport?

Dr. Ehsan Balagamwala: My favorite sport is probably basketball.

Dr. Scott Steele: Fantastic, Cavs or another?

Dr. Ehsan Balagamwala: Cavs, definitely.

Dr. Scott Steele: Fantastic. And what's a favorite place that you've traveled to?

Dr. Ehsan Balagamwala: Before we had kids, my wife and I took a wonderful trip to Paris and that was on my wife's bucket list growing up. We were really glad to be able to go there and experience the culture. It's just a wonderful place.

Dr. Scott Steele: Fantastic. And so, what do you like living here in northeast Ohio?

Dr. Ehsan Balagamwala: What I really like about Northeast Ohio is the outdoor stuff. We have some incredible hiking, which is all year round, and it's especially fun in the winter.

Dr. Scott Steele: So, what's a final take home message for our listeners?

Dr. Ehsan Balagamwala: I think the biggest take home message I would have been cancer is a journey. And when you're on that journey, you want a team that incorporates all sorts of treatment so that your cancer can get treated appropriately. Not every treatment is appropriate for every patient, but I think the team is what really matters. That's what I think we're extraordinarily lucky with our tumor boards and our collaborations is not every patient needs SBRT, not every patient needs surgery nor immunotherapy, but for patients a combination of those is helpful and that's where I think we excel is really a team of teams.

Dr. Scott Steele: Well, it's been an absolute pleasure with both you and the rest of your team to take part in that. And so, to learn more about colon cancer diagnosis as well as treatment here at the Cleveland Clinic, please visit clevelandclinic.org/coloncancer. Again, that's clevelandclinic.org/coloncancer. You can also call our cancer answer line at 866-223-8100. That's 866-223-8100. Ehsan, thanks for joining us on Butts and Guts.

Dr. Ehsan Balagamwala: Thank you so much. It's been an honor.

Dr. Scott Steele: That wraps things up here at Cleveland Clinic. Until next time, thanks for listening to Butts and Guts.