Mom Of Four, 39, Dismissed Bowel Changes As ‘IBS’ Until Blood Test Showed Severe Anemia. It Turned Out To Be Stage 2 Colon Cancer

Now, 41, the former ballet dancer and cancer survivor is sharing her story in hopes to encourage others not to ignore symptoms and push for answers.

RELATED: Colorectal Cancer Is On The Rise in Young Adults — Here’s What We Know

Duncan, who was born in New Zealand and raised in Australia, recently spoke with Business Insider about her diagnosis and how she initially attributed changes in her bowel habits to IBS, a condition she was diagnosed with at 11 after experiencing symptoms since around age 6.

Her IBS symptoms became manageable with lifestyle changes, but in her late 30s, she began experiencing constipation and persistent bloating.

During her fourth pregnancy in 2024, Duncan’s iron levels remained abnormally low, and in the months following childbirth, she developed increasing fatigue, breathlessness, dizziness and severe anemia.

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A post shared by Danni Duncan – Womens health & fitness coach (@danni.duncan_)

A colonoscopy in May 2025 was performed to determine the cause of her symptoms and revealed a tumor in her colon.

To combat the disease, she underwent surgery to remove the tumor, along with a right hemicolectomy [surgery to remove part of the large intestine] and the removal of 17 lymph nodes, as per Business Insider.

Thankfully, no cancer was found in the lymph nodes, but cancer was found in nearby lymphatic channels, resulting her Stage 2B diagnosis. Her treatment also consisted of four rounds of chemotherapy to reduce recurrence risk.

When colon cancer is caught in stages 1 through 3—can often be treated successfully with surgery and, in some cases, chemotherapy.

“Stage 1 through 3, all of those patients get surgical therapy if they’re healthy enough to tolerate it. Stage 2 is a little bit more in between,” Colorectal Surgeon and Surgical Oncologist Dr. Heather Yeo previously told SurvivorNet.

“It really depends on the depth of the tumor into the colon wall and the risk that it has to spread. If it has bad features– for example, if when they look at the pathology slides under the microscope, if they see that it’s involving some of the vessels nearby, then that is a higher risk factor. And then, those patients might be more likely to benefit from chemotherapy,” Dr. Yeo continued.

It’s important to note that for many people diagnosed with colon cancer, chemotherapy is a key part of treatment—and it’s often well-tolerated.

Sometimes, chemotherapy is recommended prior to surgery—especially if the tumor is large or has spread beyond the colon. This is known as neoadjuvant chemotherapy, and its goal is to shrink the cancer so that it can be more effectively removed during surgery. However this was not that case for Duncan.

Duncan, who received her colon cancer diagnosis when her daughter was 7 months old, celebrated in November 2025 when follow-up CT scans and a colonoscopy showed no evidence of cancer.

She now undergoes annual CT scans and colonoscopies every two years to monitor for any signs of recurrence.

Duncan, who is prepping to run in the New York City marathon, encouraged anyone reading her story to, “Stand up for yourself. Be like, ‘I’m not too young.’ … If you’ve got symptoms, push, find another doctor.”

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A post shared by Danni Duncan – Womens health & fitness coach (@danni.duncan_)

Duncan, who turned 41 on August 11, captioned her birthday Instagram post, “How grateful for another lap around the [sun]. 41 how spectacular.

“And so far nothing bad has happened. I’ve had a series of unfortunate birthdays and this time last year I was about to go into round 3 of chemo. It is such a privilege to get older and I will never complain about ageing – because isn’t that the goal.”

She continued, “Feeling the strongest, healthiest, most loved and most content I’ve ever felt – and I’m only getting started. 4 little munchkins, and amazing husband @chrisduncan7 the most wonderful friends, an epic team, an insane community, my health, an awesome place to call home , and a life I’m building the way I want – what more could a girl ask for.

“Here’s to 59 more years of laughter and love and excitement. Learning and growing. Of gratitude.”

Colon Cancer vs. GI Symptoms

Gastrointestinal problems can be caused by many factors. One important thing to remember is that colorectal cancer is usually a slow-growing cancer, so symptoms may not be apparent until the cancer has spread. In other words, getting a routine screening, such as a colonoscopy, is very important, rather than looking out for concerning symptoms.

Dr. Zuri Murrell previously told SurvivorNet, “all colon cancer starts as these small growths called polyps. And these polyps have no signs, no symptoms. The only way you can know you have them is if you do a colonoscopy, and you see them.” Moreover, he adds, during the colonoscopy, the polyps can be removed.

However, there are some key symptoms that should prompt you to check with your doctor about potential colorectal cancer. According to the CDC, these include:

• A change in bowel habits
• Blood in your stool
• Diarrhea, constipation, or a feeling that you’re not completely emptying your bowels
• Persistent abdominal pain
• Unexplained weight loss

According to the Dana-Farber Cancer Institute, while IBS and colorectal cancer share some symptoms, especially in bowel habits, “Colorectal cancer may have additional symptoms of blood in the stool, weight loss, fatigue, and a feeling of incomplete bowel movements.”

Cancer Research Legend Urges Patients to Get Multiple Opinions

Understanding  & Treating Colorectal Cancer

Colon cancer is a type of cancer that affects your large intestine (colon) or the end of your intestine (rectum). Your doctor might call this type of cancer colorectal cancer.

The cancer starts when abnormal lumps called polyps grow in the colon or rectum. If you don’t have these polyps removed, they can sometimes change into cancer.  It takes up to 10 years for a colon polyp to become a full-blown cancer, according to SurvivorNet experts. If you get the recommended screenings, your doctor will have time to remove any polyps that form, before they can cause problems.

While experts don’t know exactly what causes colon cancer, they do point to certain risk factors, such as diet, smoking tobacco, and drinking alcohol. Having a family history of colorectal cancer can also increase the risk.

Both men and women can get colon cancer. Overall, it is the third most common cancer in people of both genders in the United States. But it’s also very preventable, with the recommended screenings.

Dr. Heather Yeo, colorectal surgeon at Weill Cornell Medicine, wants to remind people how far the treatment of this disease has come.

“One of the most exciting things about my job is that we’ve made a lot of progress on treatment options,” Dr. Yeo said in a previous interview with SurvivorNet. “However … while they’re living longer, [patients] are still living with colon cancer.”

She explained that patients with stage I to III colon cancer typically need to undergo surgery.

Choosing the Right Surgery for Your Colon Cancer While Avoiding Marketing Gimmicks 

During surgery, the surgeon removes the section of the colon with the cancer, along with nearby lymph nodes — a procedure that’s known as a partial colectomy. Surgeons can perform it through an open incision, but increasingly it’s being done laparoscopically through several small incisions using specialized tools. Surgery is followed by chemotherapy to get rid of any cancer cells that might have been left behind.

Related: The Type of Colon Surgery Depends on the Location of the Tumor

After a partial colectomy, surgeons typically reconnect the two ends of the colon. But in some cases, the surgery creates enough of a disruption in the colon that it becomes difficult to have a normal bowel movement afterward. In that case, the surgeon will perform a procedure called a colostomy, creating a temporary or permanent opening through the belly through which stool can exit the body. Wastes collect in a pouch worn on the outside of the abdomen, called an ostomy bag.

“A colostomy or an ostomy, is taking the bowel and attaching it to the skin so the bowel movement would go into a bag, rather than out the anus and rectum,” Dr. Daniel Labow, chief of surgical oncology at Mount Sinai Health System, told SurvivorNet in a previous interview.

Colostomy sounds much worse than it is. “Once you get over the psychosocial effects, you can lead a totally normal life,” Dr. Labow says. “It’s not painful. It’s just getting used to a different way.”

The Spike in Colon Cancer Cases in Young Adults

The average age people are diagnosed with colon cancer is 68 for men and 72 for women, according to the American Cancer Society.

However, the National Cancer Institute reports that since the 1990s, colorectal cancer cases have been rising among adults younger than 50. Research published in CA: A Cancer Journal for Clinicians found that the proportion of cases in people younger than 55 “increased from 11% in 1995 to 20% in 2019.”

“We know rates are increasing in young people, but it’s alarming to see how rapidly the whole patient population is shifting younger, despite shrinking numbers in the overall population,” cancer epidemiologist and lead study author Rebecca Siegel said.

Researchers are still trying to determine why younger people are being diagnosed in more significant numbers. Some experts point to risk factors, which include obesity, physical inactivity, and smoking, as a possible explanation for the increase.

“We don’t know for sure why we are seeing earlier onset and death from colon cancer,” Dr. Yeo explained.

“It is likely a combination of factors, including diet and genetics as well as access to care and some environmental factors.”

WATCH: How Doctors Look for Polyps.

Most colon cancers can be prevented if people are regularly screened. The screening usually involves a colonoscopy, in which a long, thin tube attached to a camera is used to examine the colon and rectum. If no polyps are discovered, the following screening won’t be needed for ten years.

“We know that colon cancers can be prevented when polyps are found early,” Dr. Yeo told SurvivorNet. “Lowering the screening age helps somewhat with this, but access to care is a real problem,” Yeo added.

The U.S. Preventive Services Task Force (USPSTF) lowered the recommended initial age for a colorectal screening from 50 to 45 in 2021.

The American Cancer Society had recommended the same change in 2018. Since then, the American Gastroenterological Association and the U.S. Multi-Society Task Force on Colorectal Cancer have also supported lowering the recommended starting age.

Pushing For A Correct Diagnosis

When it comes to your health, be a little pushy. You know your body better than anyone else. When you see a doctor for a problem, don’t hesitate to make sure that your question is fully answered and that you are comfortable with the plan moving forward. From a doctor’s perspective, every problem should have a diagnosis, a treatment, a plan for follow-up, and a plan for what happens next if the treatment doesn’t work.

As a patient, if you don’t feel like each of these four things has been accomplished, just ask! Even if it requires multiple visits or seeing additional providers for a second opinion, always be your own advocate.

The Importance of Being Your Own Advocate

Dr. Zuri Murrell, director of the Cedars-Sinai Colorectal Cancer Center, previously told SurvivorNet that healthcare guidelines are meant to do the right thing for the largest number of people while using the fewest resources.

“The truth is you have to be in tune with your body, and you realize that you are not the statistic,” he said.

Dr. Murrell told SurvivorNet that not every patient will “fit into the mold,” so it’s important to educate yourself and be your own health care advocate.

“Every appointment you leave as a patient, there should be a plan for what the doc is going to do for you, and if that doesn’t work, what the next plan is,” Dr. Murrell advised. “And I think that that’s totally fair. And me as a health professional that’s what I do for all of my patients.”

Questions To Ask Your Doctor

If you have a cancer screening coming up or have recently had one, you may have questions you want answered. SurvivorNet’s proprietary AI tool “My Health Questions” is designed specifically for patients and caregivers.

WATCH: How One Cancer Survivor and Her Sister Used “My Health Questions” to Navigate Care

This powerful resource is embedded across the SurvivorNet website and delivers structured responses grounded in clinical guidelines and medically reviewed research to help people better understand their treatment options and feel more confident navigating care.

My Health Questions can also help patients come up with useful questions ahead of their next appointment.

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Contributing: SurvivorNet Staff

Learn more about SurvivorNet's rigorous medical review process.

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