RUSH Surgeon Saves Monkey’s Life in First-Of-Its-Kind Procedure

Surgery removed cancer from a langur at the Lincoln Park Zoo. The procedure may help save the species.
dr. kerstin stenson in scrubs kneeling to check on a langur with black fur and tubes affixed to its mouth in an operating room with support medical staff surrounding the table

When Kerstin Stenson, MD, went to medical school, she expected a career dedicated to helping save lives and relieve her patients’ pain. She never would’ve guessed that one of those patients would be a primate at Lincoln Park Zoo.

Zhang is a Francois langur, an endangered primate — and a RUSH patient. Two surgeries and many checkups later, Zhang is now cancer-free. It’s the first time a team has been able to identify and treat a Francois langur with oral cancer — saving its life and potentially saving the entire species.

Coming up with a plan

The cancerous tumor in Zhang’s mouth was first identified in 2021 by the zoo’s director of veterinary medicine, Kathryn Gamble. Historically, this kind of cancer had only been detected at the end of the langur’s life or after the langur had died from the disease.

Having found the tumor early on, Gamble developed a treatment plan that required a complex surgery. She knew she would need help. So she reached out to Stenson, director of RUSH’s head and neck cancer program.

Stenson and Gamble collaborated on a plan for surgery and recovery. Stenson brought her entire operating room team with her to the zoo, where they performed the procedure.

When it came down to the operation, Stenson said it wasn’t much different from operating on a human.

“Zhang’s head is the size of a baby’s head — but the teeth are much sharper. We were able to work our way around that.”

Zhang did great in surgery and post-op. About a year later during a routine reevaluation, the zoo's veterinarian team determined Zhang would need another surgery to assist with his recovery. Stenson returned to the zoo to perform the second procedure to help patch up some of the exposed bone from the original surgery. Zhang was back to eating and interacting with his family group in no time.

Saving the species

A year and a half after his first procedure, a final checkup confirmed Zhang is officially cancer-free. It’s a major triumph for Stenson and Gamble, with massive implications for the endangered species, setting the groundwork for cancer-fighting processes to help other Francois langurs, and potentially other animals.

“Dr. Kerstin saved his life. We’ve developed a really solid plan that allows us to do what we need to do, while making sure the animal is comfortable,” Gamble said. “We were able to make sure that he got back with his family group, and now I think we can say we’ve saved the whole species line.”

For Stenson, the opportunity was something special to be a part of, and something she’d eagerly do again.

“How it all came together was nothing short of amazing. The teamwork and all the planning that went into this was crucial, and I’m so touched to have been able to be a part of this entire experience,” Stenson said.

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