A 31-year-old marathon runner misdiagnosed with norovirus found to have stage 3 colon cancer.

Katelyn Jonozzo, a 31-year-old marathon runner, was living a physically active life and showed no signs of colon cancer until a sudden health crisis in February. After experiencing severe abdominal pain and bloating, she initially suspected she had contracted norovirus, a stomach virus that was common in her area. However, a visit to the ER led to a shocking diagnosis of stage 3 colon cancer, with secondary cancer in her abdomen.

Jonozzo had always been dedicated to staying fit. As a child, she practiced gymnastics five days a week, and later transitioned to marathon running in her 20s. She followed a rigorous fitness routine, including early morning gym sessions before her job as a supply chain analyst. By 2024, she had qualified to run the prestigious Boston Marathon in 2025. However, her plans changed when she suddenly began feeling intense abdominal pain and nausea in February.

At first, Jonozzo attributed her symptoms to norovirus, as she was experiencing bloating and vomiting, which are common symptoms of the illness. But when the pain worsened, and her friends encouraged her to seek medical attention, she agreed to visit the hospital, fearing the possibility of appendicitis. After undergoing an MRI, doctors discovered a large tumor in her colon that was close to rupturing. Within hours, Jonozzo underwent an emergency surgery that removed a part of her colon and led to a colostomy.

Jonozzo's diagnosis was a complete surprise, as she had never shown any previous signs of colon cancer. She had always been healthy, and the tumor was only discovered after an MRI revealed its presence. Her doctor explained that the tumor had likely been growing for about a decade, a fact that left her stunned. Despite this, Jonozzo's disciplined mindset helped her stay focused on what needed to be done next, even in the face of such a life-altering diagnosis.

After the surgery, Jonozzo was forced to adjust to life with a colostomy bag. The initial shock of the diagnosis and the life-altering surgery left her reeling, but she soon focused on her recovery. Chemotherapy began shortly after the surgery, and Jonozzo remained determined to stay positive. She surrounded herself with affirmations and sought support from others, including the cancer community, to help her through the challenging months.

Throughout her chemotherapy, Jonozzo had to modify her exercise routine. While she could no longer stick to her usual marathon training, she found solace in outdoor walks and short jogs. The colostomy bag, though initially a source of self-consciousness, became a part of her daily life, and she eventually embraced it. Connecting with other young cancer patients through support groups helped her find confidence, and she even became more open about her condition by attending the pool or gym with the bag visible, which boosted her self-esteem.

By August, after seven months of chemotherapy, Jonozzo was officially cancer-free. She underwent a colostomy reversal in November and eagerly awaited her first post-treatment screening, which would help her establish a new monitoring schedule. Though nervous about returning to her workout routine after the surgery, she was excited to regain her strength and return to the active lifestyle she once had.

Jonozzos journey has sparked new passions, including advocating for cancer awareness. She plans to run three marathons in 2026, with the goal of re-qualifying for the Boston Marathon. Her first marathon of the year will be the Cleveland Marathon in May, where she will serve as team captain for a cancer fundraising group. Through this experience, she has discovered a new confidence in herself and a renewed appreciation for life, saying, "I truly believe it was one of the best things that ever happened to me. I would not trade this experience for anything."

Author: Zoe Harrison