Devon Still and Leah Credit: Gilbert Carrasquillo/FilmMagic

So strong! NFL player Devon Still shared on Tuesday, January 12, that his 5-year-old daughter, Leah Still, has beaten cancer after an 18-month battle.

Little Leah was diagnosed with stage IV neuroblastoma in June 2014, and doctors said at the time that she had a 50 percent chance of surviving. She received an outpouring of support from sports fans who dubbed her "Leah Strong" as her pro-athlete dad documented her fight against cancer. On Tuesday, Devon announced that Leah had won.

The Houston Texans defensive tackle, 26, elaborated via Instagram and Sqor on Tuesday. "With Leah finishing her last treatment last night, I can really say my daughter BEAT CANCER! Words can't describe how proud I am of this girl. No matter how hard it got or how painful the treatments were (and it was pretty bad a lot of the times) she never gave up!" the proud papa gushed. "I want to thank everyone who followed us as I documented her fight on social media. The amount of support we received was beyond amazing! I can honestly say that you all made a big difference. Every time we received bad news or felt like it was coming to a point were we couldn't fight anymore, I would go to the comments you all wrote cheering us on and it would make us fight so much harder. I ask that since Leah's fight is at the end that you follow other families journeys and cheer them on just as you did us!"

Leah went into remission in March 2015, but was too sick to accept the Jimmy V. Perseverance Award in person at the 2015 ESPYS in July. At the time, her dad received the accolade in her place and gave an inspiring speech about his daughter's courage. "At the age of 4, my daughter hadn't even began to understand what life was all about. I remember one night in the hospital, she just started putting things in her stomach and putting it in mine. She said, 'Dad, I'm taking the cancer from me and giving it all to you.' I started breaking down right there," he recalled. "She's the toughest person I've ever met and she has the mindset that nothing will hold her down."

In September, Leah walked the Kids Rock! Fashion Show in NYC, where she beamed and confidently made her way down the runway. Just last week, she met LeBron James after finishing her last treatment.

For parents and families of children facing pediatric cancer, Devon shared some invaluable advice on Tuesday. 

"No matter how hard it gets, no matter what the doctors tell you, always remain positive! Speak victory into existence," Still concluded on Sqor. "Give your child's fight with cancer a purpose. Use it to raise awareness so that you can help all kids fighting this disease. No matter how big or small your platform/following is, you will reach that one family that just needs to know they're not alone in the fight so they don't give up. Drop to your knees everyday and pray. I was never a big spiritual person but I always believed in God and knew who to turn to in the time of need."

Can't get enough of Us? Sign up now for the Us Weekly newsletter packed with the latest celeb news, hot pics and more!