With sirens echoing through the streets and all the lights flashing, a convoy of Prince Albert police cars congratulated one of their neighbours on Sunday after she was deemed cancer-free.

"It's pretty amazing to see how one smaller community can come together like this," said 14-year-old Chelsea Mitchell, who is now recovering at home after a nearly three-year battle with cancer.

In July 2013, the Mitchells heard something no family wants to hear, that their oldest daughter Chelsea who was 12 at the time, had acute lymphocytic leukemia (ALL).

"It was very heartbreaking," Chelsea's mother Shelley Mitchell said.

"We didn't know what was going to happen or what to expect. We just knew we were going to Saskatoon to start treatment and we left our two children behind and just went."

Leaving Prince Albert meant taking away Chelsea's favourite hobby, soccer. She told CBC News she spent about five to seven days every week for 10 months of the year in the sport.

Treatment hits a bump

Eight months into chemotherapy, Chelsea's body wasn't responding to treatment.

"That's when we knew we'd have to move to Calgary and start the process to transplant so she had a stem-cell transplant on March 20, 2014 where they transplanted her stem cells and she got a new immune system," Shelley said.

Prince Albert Police

Chelsea Mitchell got a surprise convoy from the Prince Albert police on the day she was officially cancer-free. (Submitted by Shelley Mitchell)

In light of the transplant Chelsea had to stay in Calgary for four and a half months, and doctors told her if everything went well, she would be cancer free in two years.

"Our transplant doctor let us know that until that two-year mark comes you can't say cancer-free, you can say in remission but you can't say cancer-free because the first two years, if something is going to happen or a relapse is going to happen that's when it will happen," Shelley said. "So yesterday we knew it was two years post-transplant so we took it and celebrated all day."

"Congratulations Chelsea, Good Job!"

City police sprung the surprise on Chelsea after her uncle provided them with her address and then called her to be outside in 10 minutes.

"At first I thought we were in big trouble but when they drove by slowly we knew … and to hear them say congratulations to Chelsea and good job, it was amazing," Shelley said.

Chelsea had the chance to sit in the driver's seat of the cruiser as well as flip the siren on. She said she was surprised at how easy it was to create such a loud noise.

Chelsea Mitchell - prince albert police convoy

On March 20, Chelsea and her family were surprised by a police convoy celebrating Chelsea's win over cancer. Chelsea got to sit in the front seat of the police car and turn the siren on. (Submitted by Shelley Mitchell)

Now Chelsea is recovering at home in Prince Albert, walking her dog and slowly building up strength in her lungs and muscles in her legs, so one day she could step back on the soccer field.

The gesture from police was just the tip of the iceberg. While in Saskatoon and Calgary, friends and family in Prince Albert put on a couple of fundraisers where they made and sold bracelets and T-shirts with 'Team Chelsea' on the front.

"So we were getting a little bit of money from home even though we weren't here then to have the police department have a shout-out. We're truly blessed to live where we live," Shelley said.