Additional Coverage:
- A 39-year-old fitness coach mistook her colon cancer symptoms for IBS (businessinsider.com)
Danni Duncan’s Journey from Childhood IBS to Colon Cancer Survivor and Marathon Runner
Danni Duncan, 40, has faced digestive challenges since early childhood, initially diagnosed with irritable bowel syndrome (IBS) around age 11. Growing up with typical fast-food habits, her symptoms improved dramatically as an adult after adopting a diet rich in whole foods and reducing alcohol intake. She became a fitness and nutrition coach and began training for marathons, embracing a healthy lifestyle.
However, in her late 30s, Duncan noticed troubling changes in her bowel movements, which she initially attributed to her longstanding IBS. After the birth of her fourth child in September 2024, persistent bloating and constipation led her to use fiber supplements, but the symptoms worsened. It wasn’t until she experienced extreme fatigue caused by severe anemia that a deeper problem was uncovered.
During her pregnancy, Duncan’s iron levels plummeted to dangerously low levels, and even after an iron infusion, they failed to improve significantly. Doctors initially dismissed her symptoms as typical pregnancy-related changes, advising iron supplements.
Postpartum, Duncan struggled with unusual exhaustion and breathlessness while training for a marathon, eventually dropping out of the race. Dizzy spells and near-fainting episodes prompted further medical evaluation.
A blood test revealed a hemoglobin level far below normal, signaling severe anemia. A colonoscopy followed and confirmed the presence of a tumor, leading to a diagnosis of stage 2 colon cancer.
The news was a shock, especially given her commitment to health and fitness. But thinking of her children gave her strength to face the fight ahead.
Treatment began swiftly with surgery to remove the tumor and affected lymph nodes. Although the cancer had not spread to the lymph nodes themselves, involvement of lymphatic channels raised her risk of recurrence, prompting a course of chemotherapy.
Throughout chemotherapy, Duncan maintained light exercise routines despite battling fatigue, nausea, and cold sensitivity caused by the medications. One of the hardest sacrifices was stopping breastfeeding her 7-month-old daughter due to chemo drug risks.
By November 2025, scans and follow-up tests showed no signs of cancer. Duncan now faces ongoing monitoring but is focused on recovery and returning to her passion for running. She is training for the New York City Marathon, an event she postponed due to her diagnosis, and plans to run alongside her husband to raise awareness for colon cancer through the Jodi Lee Foundation.
Duncan emphasizes the importance of paying attention to unusual symptoms, especially for younger adults, and encourages others to advocate for themselves when seeking medical care. Her message is clear: don’t dismiss persistent changes in your health-early detection can save lives.
Read More About This Story:
- A 39-year-old fitness coach mistook her colon cancer symptoms for IBS (businessinsider.com)