US actor Chadwick Boseman poses in the press room during the 2019 American Music Awards at the Microsoft theatre on November 24, 2019 in Los Angeles.
  • "Black Panther" star Chadwick Boseman died August 28, four years after being diagnosed with stage three colon cancer. He never spoke publicly of his illness.
  • Boseman was 43 years old. Data suggest bowel cancers are on the rise among people younger than 50. 
  • Young people are more likely to be diagnosed with advanced stages of colorectal cancer.
  • Risk factors include genetics and diet.
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Chadwick Boseman, the actor best known as the star of "Black Panther," died of complications related to colon cancer August 28, four years after being diagnosed with the disease.

Boseman's death came as a shock to fans worldwide. He had never publicly spoken of the illness, and was only 43 years old when he died.

In the past three decades, research has consistently shown a rise in rates of colon cancer and related illnesses like rectal cancer among young people.

People over the age of 50 are still at greater risk of developing colon cancer overall. However, people under 50 are more often diagnosed with hard-to-treat, advanced forms of the disease.

One study on 1.2 million colon cancer patients from 2004-2015 found that most (51.6%) of the patients under 50 were diagnosed with stage three or four. 40% of people over 50 were diagnosed at those later stages.

Bowel cancers can be difficult to diagnose because the symptoms — such as abdominal pain, constipation, diarrhea, weight loss, fatigue — are shared with ailments like hemorrhoids, inflammatory bowel disease, or irritable bowel syndrome. What's more, routine testing isn't offered to people under the age of 50 in many countries, including the US.

If caught early, colon cancer is very treatable, and the five-year relative survival rate is about 90% if the cancer doesn't spread, according to the American Cancer Society

But it's common for patients to have no symptoms at all until later stages of the illness. That's why it's important to get screened regularly, especially if you have risk factors.

Obesity, poor diet, and genetics can all increase risk of bowel cancers

Genetics is a major risk factor for colon cancer. There's evidence that cases of bowel cancers are more likely in younger people with a family history of the disease.

Eating habits also play a role in bowel cancer risk, and diets low in fiber and/or high in red meat and processed meat can increase the risk of the disease. Some experts have hypothesized that the recent popularity of meat-heavy diets like keto and paleo is partly to blame for rising cancer rates

Obesity is also linked to an increased risk of bowel cancer, as are poor health habits like smoking and excessive alcohol use.

Race and colon cancer

Black people may be disproportionately affected by colon cancer in the US, studies have shown.

That is, in part, due to racism, and barriers to getting medical treatment.

Stress stemming from racism and the hurdles African Americans historically face in the US also have a tangible impact on health, studies show.

Symptoms like rectal bleeding, unexplained weight loss, and constipation or diarrhea can be warning signs of colon cancer

Many symptoms of colon cancer can also indicate more mundane illnesses. 

For instance, changes in bowel movements like constipation or diarrhea could indicate colon cancer, but also a plethora of other ailments, including infections, irritable bowel syndrome, or inflammatory bowel disease.

Abdominal pain, unexplained weight loss, and fatigue can also be symptoms. 

A major warning sign for colon cancer is rectal bleeding or bloody stool. While this could be hemorrhoids, you should also consult a medical professional if you experience this alarming symptom.

Another unique indicator of colon cancer is the feeling of being unable to empty the bowels, according to the Mayo Clinic

Colon cancer treatment

The first-line treatment for colon cancer at stages zero or one is surgery to remove the affected part of the colon. 

However, past stage two, chemotherapy is considered, particularly if it has perforated the colon and/or looks at-risk of resurging after surgery. Stage two is when the cancer is still localized but is growing.

Stage three, when the cancer has spread to nearby lymph nodes but not to other organs, requires surgery and chemotherapy, with additional radiation if the cancer is advancing quickly. 

At stage four, when the cancer has spread to other organs, patients undergo a combination of chemotherapy and surgery, radiation therapy, and other targeted treatments, to either try to treat the cancer or to alleviate the pain associated with it.

Everyone 45 and older should get screened regularly for bowel cancer, but so should younger people at high risk

Bowel cancer is diagnosed with a variety of tests, including a stool test, colonoscopies, x-ray or CT scan of the bowels. A regular physical exam can help identify any abnormalities early, and detect the cancer sooner. 

Treatment can vary depending on how far the cancer is advanced and where in the bowel it is located, but includes some combination of surgery, radiation therapy, chemo therapy and immunotherapy. 

The American Cancer Society recommends that all adults over 45 be tested regularly for colon cancer, even if they have no symptoms. However, your personal risk factors can determine how frequently you should be tested, so it's best to talk to your doctor about your health history and schedule tests accordingly.

"It is very clear that signs and symptoms that might indicate colorectal rectal cancer in those under 50, and particularly rectal bleeding, should be evaluated by a health care professional promptly and not dismissed as 'only hemorrhoids' or 'normal,'" Dr. David Greenwald, a professor of medicine and gastroenterology at the Icahn School of Medicine at Mount Sinai, previously told Insider.

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