Doctors told a woman she was too young for colon cancer and dismissed her symptoms for years. At 22, she was diagnosed with stage 3 colon cancer.

• Kirsten Scheller first started experiencing blood in her stool when she was 19.
• After seeing doctors for years, she was diagnosed with stage 3 colon cancer at 22.
• Now 36 and cancer-free, she advocates for early-onset cancer awareness.

For years, Kirsten Scheller was told the same thing by her doctors: she was too young and too active for colon cancer.

In 2010, when she was a 19-year-old college sophomore in Saint Paul, Minnesota, Scheller started having a few symptoms: mainly, blood in her stool, plus occasional bloating and fatigue.

"Being in college and being a woman, I didn't really think much about those symptoms," Scheller, now 36, told Business Insider. Plus, she was in great shape: she played three sports in high school, and continued to hike and run in college. "I was extremely active and eating well," she said. "I was training for a duathlon and doing a lot of yoga."

Her mother, a nurse, saw cause for concern anyway and pushed her to see a GI specialist. Over the next two years, as the blood in her stool got worse, she lost track of the total number of doctors she saw. Because of her age, overall good health, and lack of family history, they all said the same thing: Maybe it was stress, or internal hemorrhoids.

It turned into a perpetual loop of dismissal and encouragement to monitor symptoms. "I was sent home and told to come back if it continues to happen," Scheller said. "And of course, it just continued to happen."

Then, when she was 22 and a month away from college graduation, she saw one more GI specialist. Then a screening led to her being diagnosed with stage 3 colon cancer.

"It was just a mix of emotions," she said. "I was scared, but also validated just from having these symptoms and having a gut feeling that something was wrong and finally having an answer for it."

An almost-stage 4 diagnosis

Before graduation, Scheller saw a gastroenterologist at Minnesota Gastroenterology, who recommended a flexible sigmoidoscopy, which is less invasive than a colonoscopy and doesn't examine the entire colon.

Because Scheller was somewhat awake for the procedure, she caught a glimpse of the tumor before she fully knew what it was.

"I just remember the scope turning a corner and seeing a trail of blood," she said. "And then as they continued to move through, we saw this really large mass."

The staff stayed calm and told her they would biopsy it, giving Scheller a clue that "something was off." Then, a nurse came into Scheller's room before the doctor had a chance to speak to Scheller and expressed her condolences to Scheller and her mom. "We knew that probably wasn't just a benign type of tumor," she said.

Days later, Scheller got the call — she had colon cancer. She was at her parents' house while they were at work. The worst part, she said, was relaying the news to them.

She wouldn't learn what stage of colon cancer she had until her colon resection surgery, which removed a foot of her colon. She also had 24 lymph nodes removed, as the cancer had spread.

When she woke up, she learned she had stage 3 colon cancer. Based on the types of cancer cells they found and how quickly they were dividing, her doctor told her that she'd likely have had stage 4 had she waited a few more months.

Knowing how much worse it could have been, "just hit even harder," she said.

A fresh college grad in chemo

Being diagnosed so close to graduation, Scheller was able to complete her finals at the hospital and walk to get her degree as planned.

Then, she jumped right into treatment: intensive chemotherapy for the next nine months.

Emotionally, it was hard to put a hold on her post-college dreams as a freshly minted neuroscience grad. "You go through college thinking, 'What is my first job going to be? Where am I going to live? You're kind of excited to start this adult life,'" she said.

Then there were the treatment side effects. Back in 2010, less was known about fertility preservation options for cancer patients. To try and preserve her egg quality, Scheller was injected with Lupron, which shut down her ovaries during chemotherapy. The result was "full-blown menopause," Scheller said, which included experiencing hot flashes and headaches while she was being treated.

She also developed "horrible neuropathy" from the chemotherapy, leading to pain and tingling in her hands and feet after treatment was finished. She went to physical therapy for months before starting her first job to regain hand function. "I had to teach myself how to write again," she said. Of all the side effects, neuropathy was the worst — she went to physical therapy and acupuncture for years after treatment was over to manage symptoms.

All the while, her social network was in flux. While she had a wonderful support system — her parents, older sister, childhood friends, and extended family — her college relationships took a hit.

"Unfortunately, many friends that I had met kind of drifted away or didn't know how to support someone at that age going through advanced-stage cancer," she said, though she didn't blame them. "That was the hardest part, this grief of losing friendships while I had to grow up extremely quickly and just not know what the next week was going to look like."

She's glad more people know about the risks

By the end of 2012, Scheller was cancer-free and is still in remission today. Because she has an unknown genetic mutation that predisposes her to quickly growing precancerous polyps, she gets more frequent screenings than she otherwise would. She started with one every three months and is now on a 9- to 12-month schedule.

Otherwise, her life feels pretty normal. She bought a starter home in Minneapolis at 26, and still lives there a decade later, only now with her husband and two dogs. And she's worked at Medtronic, a medical equipment company, for nearly 13 years — starting shortly after she finished her cancer treatment.

In her spare time, she is training for her first half-marathon and planning a 100-mile hike in Europe. "I would've never guessed when I was 22 what I would be doing now, but I'm just super grateful to be healthy," she said.

She's also shared her story with several colon cancer non-profits to raise awareness around early symptoms and screening. Luckily, she's noticed a positive change over the years.

"Now, we're actually talking about it," she said. While she feels there's still stigma around certain symptoms like bloody stools, "there's social media, people are sharing their stories." Her hope is that people who hear these stories take action and get screened if they experience common colon cancer symptoms.

Knowing what she knows now, she would also recommend advocating for a full colonoscopy over a flexible sigmoidoscopy for screening. While a colonoscopy usually requires anesthesia and is a more involved procedure, it's also more thorough in examining the whole colon.

Even with the days of her treatment long behind her, it's still an experience she thinks about every day. "My badge picture still shows me in a full wig," she said, having started her job right after finishing chemotherapy. "I have a daily reminder, when I look at that picture, of everything I went through."