When friends of cancer patient Anthony Lyons of Phoenix, AZ, posted a request on Facebook for “photo doggies for Anthony” to cheer him up, they did not anticipate the overwhelming response the request would receive.

Lyons, 16, was diagnosed with acute lymphoblastic leukemia last July. Therapy dogs visit him twice a week at Phoenix Children’s Hospital. Seeing his spirits lift when the dogs visit, a family friend began a Facebook event wherein people could submit pictures of their doggies for when the therapy dogs were not available.

The Facebook page went viral. Hundreds of thousands of dog, cat, and other pet photos and well-wishes flooded the page. Some people posted pictures of their own pets with cancer.

“It’s reassuring because you look at the pictures of the dogs; they’re sick all the time but they’re still happy. They’re happy to be alive. I’ve never met a sad dog,” Lyons told the Associated Press.

Lyons told Fox10 Phoenix that his mother shows him all the pictures posted to the page. “It really helps, the pet therapy. Like I can be in here having a really bad day and then one of the dogs will show up and it will be the highlight of the day.”Animal-assisted therapy programs are invaluable to cancer patients like Anthony Lyons.