#TeamLandon

(CNN) -- He's only 3 years old, but Landon Riddle is already the focus of a medical marijuana fight in Colorado.

Landon has acute lymphocytic leukemia, or ALL, a cancer of the blood and bone marrow. It's the most common cancer in children.

His mother says his condition has improved so much following treatment with medical marijuana that chemotherapy isn't needed. But the Children's Hospital of Colorado, she says, disagreed.

It all started back in September 2012. Landon, then 2, was living with his mother, Sierra Riddle, in St. George, Utah, when he developed a sore throat and swollen lymph nodes. The emergency room doctor said it was a virus and sent him home.

Two days later he went back. His armpits were swollen.

"They thought it was either a virus or infection in the lymph nodes, so they gave him some antibiotics," Sierra Riddle says.

But on the fifth day, his mother says she was changing his diaper and noticed his groin was also swollen, as well as his abdomen and throat. He was having trouble breathing.

That time, she got a frightening diagnosis: CANCER.

Landon was flown to a children's hospital in Salt Lake City, Utah.

"His whole chest was full of Leukemia tumors, which is why he couldn't breathe," his mother says. "They started him on chemo, but told us that he probably wasn't going to make it."

Landon's cancer had quickly progressed, leading doctors to give him an 4-8% chance of survival, she says.

In general, ALL is one of the most curable cancers. According to the American Cancer Society, more than 90% of children diagnosed with the disease survive.

Chemotherapy is the standard treatment, and Riddle says doctors put Landon on a four-year treatment plan. The first two months of chemo went fairly well, but then Landon became extremely ill.

"Most days he couldn't get off the couch," Riddle remembers. "He would just lay there and throw up and throw up."

Riddle says he also developed neuropathy -- a symptom of nerve damage that can cause weakness, numbness and pain -- in his legs that left him barely able to walk.

Around that time, a friend set up a Facebook page called Offer Hope for Landon, and recommendations started streaming in, including several endorsing cannabis -- medical marijuana -- as a treatment.

Medical marijuana, however, isn't legal in Utah. Still, desperate for answers, Sierra Riddle and her mother, Wendy Riddle, started looking into it.

They considered going to California or Oregon. Then their research led them to Colorado.

 

In the end, she decided she had nothing else to lose and moved to Colorado. She rented a room, got Landon's medical marijuana card and began giving him marijuana -- THC for the pain and nausea, but also CBD. The dose was based on Landon's weight. He first took it in oil form, but now takes a pill.