A fit and healthy 30-year-old woman training for her first half-marathon received a devastating stage 4 colon cancer diagnosis after doctors repeatedly dismissed her severe symptoms as a stomach bug or hormonal issues.
From Peak Fitness to Unexplained Illness
Karina Ureña from California was at the peak of physical fitness, eating clean and running daily, when she began experiencing what she thought were period cramps in the months leading up to her February 2025 race. Over six months, her condition deteriorated dramatically into regular vomiting and severe pain.
'I thought it was just my period,' Ureña said. 'I was eating clean, running daily and felt the healthiest I'd ever been. Cancer wasn't even on my radar.'
Her dream vacations to Key West, Florida, Maui, Hawaii, and Mexico were overshadowed by sudden sickness. 'I'd be driving and suddenly have to pull over to vomit,' she recalled. 'I told myself it was stress, jet lag, or food, but deep down, something didn't feel right.'
The Devastating Diagnosis
By October 2024, Ureña was constantly fatigued and losing weight rapidly but continued training for the 13-mile San Francisco Half Marathon. During the race itself, she vomited five times but pushed through to finish. 'I didn't want to admit to myself that something serious might be wrong,' she said.
After visiting the emergency room, doctors prescribed anti-nausea medication that only masked the pain. It wasn't until February, after several medical visits, that her primary care doctor ordered the scan that revealed the shocking truth.
The results came through on her patient app before her doctor had even returned to the room. 'I'll never forget reading the words, a 3.6-inch mass on my ovary, cancer that had spread to my liver and lungs. My heart dropped,' Ureña said.
Doctors confirmed the cancer had originated in her colon before spreading to her ovaries, liver and lungs. The mass on her ovary was about the size of a small orange.
A Growing Trend Among Young Adults
Ureña represents an alarming trend of young, otherwise healthy Americans being diagnosed with colon cancer before their 50th birthday. Approximately 2,600 people under 50 years old are now diagnosed with colon cancer in the US every year.
Cases are expected to double between 2010 and 2030 after having risen two percent a year since the early 2000s. Doctors remain puzzled by the cause, suggesting everything from rising obesity rates and sedentary lifestyles to disrupted microbiomes and environmental toxins.
Yet these explanations fail to account for why healthy, active individuals like Ureña are developing the disease. Her family history included her father beating stage 3b colon cancer in 2015, but genetic testing confirmed her case wasn't hereditary.
'That's the part that really messes with my head,' Ureña said. 'But it also reminds me that anyone, at any age, can get this.'
Treatment and Hope for the Future
Following her diagnosis, doctors initially suggested a full hysterectomy, which would have ended Ureña's hopes of becoming a mother. 'The thought of losing that part of me was unbearable,' she said.
In March 2025, she underwent surgery to remove the largest tumour on her right ovary. During the procedure, doctors also removed tissue from her colon, resulting in Ureña being fitted with a colostomy bag.
'Learning how to live with a colostomy bag has been a huge adjustment, both physically and emotionally,' she admitted. 'But I'm slowly getting used to it. It's become part of my fight, a reminder that I'm still here and still healing.'
After surgery, Ureña began 11 rounds of chemotherapy and continues to seek medical advice about potentially saving her uterus. The American Cancer Society states only about one in ten patients diagnosed with distant colon cancer survive for five years after diagnosis.
Through her TikTok platform, Ureña shares her cancer journey while finding strength in small moments and her mother's unwavering support. 'My mom has been my rock,' she said. 'She takes me out into nature, even if it's just to sit and listen to the birds. Those moments remind me I'm still me.'
Her message to others is clear: 'Listen to your body. Don't ignore persistent pain or changes that don't feel normal. Prevention can save your life. If I'd gone to the doctor sooner, maybe things would be different. But all I can do now is fight, and I'm not giving up.'
