Kerstin Stenson, MD ’88, FACS, is one of Chicago’s most experienced experts in otorhinolaryngology. But she didn’t expect her decades of research and clinical care in head and neck cancer surgery would lead to a lifesaving treatment for an endangered small monkey at Chicago’s Lincoln Park Zoo.

Joining forces with the zoo’s veterinarians, Dr. Stenson and her team completed successful surgeries on Zhang, the zoo’s only male François’ langur, to remove a cancerous tumor in his mouth. He’s been cancer-free for two years, according to zoo officials.

Dr. Stenson, a native of Grayslake, Illinois, didn’t grow up with doctors in her family. She took a shine to science and anatomy classes, and studied at Luther College in Iowa and Chicago Medical School. She did her residency at University of Illinois Hospital, where she met her mentor, Barry Wenig, MD, MPH, PhD, FACS.

“I wanted to be like my mentor, so my mentor was a head/neck surgeon,” Dr. Stenson said. “Almost always, you can effect the change and see it in surgery. There’s so much more you can do for a cancer patient than just operate on them. I like the long-term human connection.”

She led UChicago Medicine’s head and neck cancer surgery department before Rush University Medical Center recruited her 10 years ago.

“I have an even more profound respect and amazement for the zoo staff and how they care for and prioritize the precious animals around us.”

So, how did Dr. Stenson end up operating on a primate roughly the weight of a human infant? It started with an out-of-the-blue email from Kathryn Gamble, DVM, director of veterinary services at Lincoln Park Zoo.

Dr. Gamble discovered Zhang’s tumor inside his mouth, on the hard palate and gum tissue around his teeth, in 2021.

“She was worried that I thought it would be a hoax,” Dr. Stenson said of the email asking for her help.

On the contrary, Dr. Stenson was intrigued and jumped at the opportunity to help, she said. 

Dr. Stenson and her team from Rush examined Zhang twice, deciding on surgery to treat him. François’ langurs have a sensitive digestive system where they can’t go very long without eating, so pain management for Zhang was particularly essential, Dr. Stenson said. 

On the operating day, Dr. Gamble’s team anesthetized Zhang and inserted a catheter into his tail. Dr. Stenson and one of her lead operating nurses brought all of their equipment over from Rush — “all the instruments; everything that I would use for a human patient” — to conduct the roughly 45-minute procedure to remove the tumor.

The anatomy was similar enough to human patients that Dr. Stenson could apply much of the same technique, while Dr. Gamble and her team managed his anesthetic, IV, fluids and vitals.

Dr. Stenson performs surgery on Zhang (photo by Christopher Bijalba, Lincoln Park Zoo).

“His little head is like a baby’s head. We’re used to working in small openings, and he could open his mouth wide enough for me to get to where I needed to go,” Dr. Stenson said. “There were enough (similarities) to help me understand where the sensory nerves were. Dr. Gamble was able to numb those nerves for the pain.”

Zhang lost a couple of his less important teeth in the process, but overall, the procedure was successful and he recovered very well, Dr. Stenson said. His post-operative care was mostly pain management and routine examinations — and a few Disney movies to enjoy.

A healthy Zhang has been reintegrated back into his family group, according to zoo officials. 

Dr. Gamble told NBC Chicago that the treatment is groundbreaking. Before this, the type of tumor Zhang had was considered to be fatal, in part because experts hadn’t discovered it early enough to treat it.

“I have an even more profound respect and amazement for the zoo staff and how they care for and prioritize the precious animals around us,” Dr. Stenson said. “I think I was incredibly lucky. It was an amazing experience. Maybe no one will ever do it again, but I’d be happy to participate if another little monkey needs an operation.”  

Dawn Rhodes is a Chicago-based writer and editor. She’s worked in journalism for more than a decade.