Brown, 32, was filming the upcoming season of "The Challenge" in Panama last week when she collapsed on set, an insider tells Us. She was airlifted to New York City and underwent two emergency surgeries.
The reality star previously was diagnosed with ovarian cancer at the age of 22. After beating it once with chemotherapy, she learned that it had returned in June 2012. In February 2013, she announced that she was cancer-free for the second time after completing chemo again.
"I could not be more excited," she told Us at the time. "I can't stop smiling from ear to ear. I feel so free, like I have my life as my own again."
"I am still shaking," she added. "I can't describe the feeling of doctors telling you your cancer is gone -- especially when you were told this day more than likely would never come. I love it when those doctors are wrong."
Brown quickly became a fan favorite on MTV's "The Challenge" when she shared her story in the show's Fresh Meat season in 2006. She's since created the site MedGift to discuss her struggles and to help others suffering from any illness. Supporters can donate to help Brown here.