By Kathy Walsh

DENVER (CBS4)– A veterinarian at the Denver Zoo has put a king cobra with cancer in remission. Thanks to a unique treatment plan pioneered at the zoo, there is no longer any sign of cancer in the huge snake.

Determined zookeepers were able to successfully treat the cancer called lymphosarcoma.

“Which is a type of cancer that affects the scales,” said Denver Zoo Associate Veterinarian Betsy Stringer.

Concern started last February when a zookeeper noticed purplish scales. Stringer wanted a closer look.

“His size and being venomous definitely makes this a really challenging patient,” she explained to CBS4 Health Specialist Kathy Walsh.

Zoo staff kept the snake asleep with his head in a tube hooked to an anesthesia machine. It took nine X-rays to evaluate his 13-foot long body.

A biopsy confirmed the cancer. But what next?

“There’s no publication that tells me how to treat lymphosarcoma in a king cobra, so this was uncharted territory,” said Stringer.

Stringer worked with a veterinary oncologist at Colorado State University and came up with a treatment plan.

“The chemotherapy drug we used is used in domestic cats, in people,” said Stringer.

It’s a little trickier treating a cobra. In this case, a pill was put in the throat of a dead rat. The cobra was fed one every three weeks for five months. A biopsy in December showed success.

“The cancer did not come back and he’s officially in remission,” said Stringer.

This is one lucky reptile with the Denver Zoo able to tip the scales in his favor.

The zoo plans to publish its treatment plan in a scientific journal to help other sick snakes. The cobra at the zoo is considered geriatric, almost 19 years old, but zookeepers are happy to have bought him some time.

Kathy Walsh is CBS4’s Weekend Anchor and Health Specialist. She has been with CBS4 for more than 30 years. She is always open to story ideas. Follow Kathy on Twitter @WalshCBS4.