Mohammad Bilal, MD, associate professor in the University of Colorado Department of Medicine’s Division of Gastroenterology and Hepatology, didn’t always see himself as a proceduralist. But a common cancer screening procedure — and an interest in what happens afterward — changed his mind.
“One of the predominant modalities still available to detect and prevent colon cancer is a colonoscopy,” says Bilal, CU Cancer Center member. “Colon cancer is the second leading cause of cancer-related deaths in the world. Colonoscopies allow us to find precancerous polyps and remove them early.”
It’s after detection of early-stage gastrointestinal (GI) cancer that Bilal’s work — and interest — in a procedural field called third space endoscopy begins.
Third space endoscopy uses a flexible tube called an endoscope to access and treat tumors or disorders in the deeper layers of the GI tract without compromising the top layer of the GI tract. These procedures are minimally invasive, incisionless, and many patients undergoing the procedure can go home the same day.
“The fact that you can remove a tumor with an endoscope in an outpatient setting and avoid a major operation that could impair quality of life was very inspiring to me,” Bilal says. “Being able to change the course of someone’s disease is why I do this.”
Endoscopic submucosal dissection — a type of third space endoscopy procedure — was originally developed in Japan in the late 1990s. Rates of gastric cancer are much higher in East Asia, which prompted doctors to seek out a less invasive method for removing tumors within the intestinal lining. During the procedure, gastroenterologists work in the submucosal space, which is the layer below the surface, to get underneath the tumor and remove it using an electrosurgical knife.
While slow to launch in the United States, the procedure has grown in popularity over the past decade.
“It took time to adopt here because of tools, techniques, and insurance reimbursement challenges,” Bilal said. “But recently we've really started seeing a lot of uptake. Almost all major academic centers have someone like me doing these procedures. And now these procedures are part of the National Cancer Society guidelines for colon and esophageal cancers.”
At CU, Bilal — who was recruited in October 2024 to rebuild the third space endoscopy program — is the only gastroenterologist currently offering the procedure, but he is training another provider and is working on ways to continue growing the program to reach more patients.
Bilal is quick to point out that this method is not always a replacement for surgery, and he and other doctors in the division partner closely with surgeons and multidisciplinary teams to offer comprehensive care when a major operation is needed. But for the right type of patient, this procedure can be life changing.
Several conditions or early cancers that would previously have needed major surgery, such as early-stage esophageal, gastric, or colorectal cancer, can now be removed through this method. This means significant surgeries — such as esophagectomy, gastrectomy, and colorectal surgeries, which in some cases would require patients to use an ostomy bag for the rest of their life — can be prevented.
Bilal says that these procedures can take anywhere from an hour to five hours, depending on the complexity of the case. He recalls one long procedure where he was able to remove a tumor that was 14 centimeters in size, preserving the patient’s organ in the process — an outcome that would not have been possible with traditional surgery.
While third space endoscopy was originally developed for cancer treatment, the procedure has also been adapted to treat debilitating digestive disorders.
One example Bilal provides is for patients with gastroparesis, where the stomach fails to empty properly, resulting in nausea, vomiting, and bloating. In these cases, the muscle between the stomach and intestine is too thick. Gastroenterologists can use this procedure, called a gastric peroral endoscopic myotomy (G-POEM), to cut some of the muscle, allowing food to leave the stomach easier. He says this has a dramatic improvement on a patient’s quality of life.
Another condition third space endoscopy can treat is Zenker’s diverticulum, which is when the esophagus — the tube that passes food and liquid from the throat to stomach — develops a pouch at the top of the esophagus where food can get trapped, causing the person to either choke or frequently vomit. By using the procedure to cut the muscle and release the pouch, patients can eat normally again.
“If someone has to constantly ask themselves, ‘Can I go out to eat?’ — that's a huge impairment on their quality of life,” Bilal says. “To be able to give someone their quality of life back and be part of that journey, I think it's really rewarding and is why I continue to do this.”
Outside of the procedure room, Bilal has a great interest in advancing research around precancers and cancerous lesions in the GI tract.
One of his primary focus areas is on the early detection and management of early-stage GI tract cancers and techniques to improve early detection and management strategies of those cancers.
“A lot of my research revolves around various techniques in endoscopic resection and trying to figure out the optimal approach to make procedures more efficacious, reduce the risk of recurrence of these lesions, and improve the safety profile so they're less risky,” Bilal says.
As a subset of this focus, he studies and evaluates minimally invasive endoscopic tools to treat gastroenterological and pancreatobiliary conditions. And he has an interest in innovations in medical education, clinical scholarship, and curriculum development. He’s also optimistic that the university will be able to take part in a major clinical trial on a procedure called peroral endoscopic myotomy (POEM), which treats swallowing disorders by relaxing esophageal muscles.
“Our hope is that CU will be one of the sites for a landmark trial that will help us figure out different ways to improve efficacy but also reduce the risk of reflux, which is one of the more common complications of POEM,” Bilal says.