How radiation therapy is used to treat bile duct and gallbladder cancer

Ethan Ludmir, M.D., grew up watching Star Wars. But unlike other fans, his favorite character wasn’t Luke Skywalker or Han Solo. Instead, Ludmir favored a character who got much less screen time: the man tasked with controlling the Death Star’s laser beams.

Today, Ludmir’s work as a radiation oncologist in Gastrointestinal Radiation Oncology has certain similarities to the movies he grew up watching. But instead of using lasers to help the Empire, Ludmir uses radiation to help treat patients facing cancers in the biliary tract, such as bile duct and gallbladder cancer.

Now, Ludmir is sharing how radiation therapy is used to treat biliary cancer – and how the field is advancing.

What radiation therapy options are available to bile duct and gallbladder cancer patients?

Biliary cancers are relatively uncommon diseases that can occur in the bile ducts within or outside of the liver, as well as in the gallbladder. Radiation therapy for biliary cancer may be given after surgery to control a tumor from spreading or instead of surgery to provide relief from symptoms.

Common radiation approaches for biliary cancer treatment include intensity modulated radiation therapy (IMRT) or stereotactic body radiation therapy (SBRT). These photon-based approaches use image guidance to send high dose radiation directly to the tumor.

While the words “high-dose radiation” may give a patient pause at first mention, research shows dose-escalated radiation can improve tumor control and survival among biliary cancer patients while limiting side effects and damage to surrounding organs such as the liver, stomach and small bowel.

“Data from MD Anderson has demonstrated that if you can safely turn up the dial with radiation, you are more likely to control and kill off these tumors,” Ludmir says.

Proton therapy, which utilizes larger radiation particles and has different dose distribution properties compared to photon-based approaches, may also be used to treat biliary cancers.

Oncologists decide which type of radiation to use on a case-by-case basis that considers each patient’s anatomy, liver function and tumor location.

“These different radiation options are part of a toolbox of techniques. No one technique is the right choice 100% of the time, so we pick the technique that works best for each patient,” Ludmir says.

What are the challenges of using radiation therapy for biliary cancer?

The bile ducts are located in what Ludmir calls “prime real estate” near the gallbladder, liver, stomach and small bowel. Because even small movements from breathing and digestion can alter the position of the bile ducts, special techniques and technologies are used to make sure radiation is delivered precisely to the tumor site while avoiding unnecessary exposure to these neighboring organs, which could lead to damage or side effects.

Prior to treatment, patients learn how to hold their breath during radiation and are instructed to limit what they eat and drink to minimize gas bubbles in the stomach. In some cases, spacers are surgically inserted to protect parts of the body from radiation.

During treatment, radiologists use an array of image guidance technologies to accurately target tumors and avoid critical structures.

“It’s a testament to expertise and technological advances that we can treat these tumors while paying attention to how patients are breathing, ensuring we're treating exactly where we want to be and not where we don’t,” Ludmir says.

What is the process for receiving radiation therapy for bile duct and gallbladder cancers?

Radiation treatment can last anywhere from a week to multiple weeks with individual appointments lasting about an hour. Patients lie in a bean-bag-like-device molded to the shape of their body, while a pre-treatment CT scan ensures proper alignment. Aside from an intercom message announcing the radiation has begun and for the patient to hold their breath, a patient may not even notice the process is underway. Twenty minutes later, the process is complete.

“Folks often walk out of the room after the first day of treatment and say, ‘Oh, that was not nearly as bad as I thought it would be,’” Ludmir says. “It’s a misconception people have that radiation is painful.”

What’s next in the field of radiation therapy for biliary cancer?

New advances in radiation therapy for biliary cancers include everything from the types of subatomic particles to the machines used to deliver radiation. New forms of radiation are being explored in clinical trials, dose-escalation continues to advance, and equipment continues to improve.

“Advances in technology, which are often behind the curtain, are really what have allowed us to do things that weren’t possible before,” Ludmir says. “As much as technology has changed over the last five years, we anticipate even further advances in the coming five years.”

With these advances come better and better patient outcomes. And, for Ludmir, a job even more gratifying than anything depicted on screen.

“There's really nothing like seeing patients come back months and years after treatment, and they're doing well. The end result is satisfying beyond words.”

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