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Dangerous Effects of Colon Cancer, Say Experts

It's the fourth leading cause of cancer death.
FACT CHECKED BY Emilia Paluszek

Colon cancer is the fourth leading cause of cancer death in the United States. But experts say that it's one of the few cancers that are largely preventable, thanks to screenings. Good reasons to follow your doctor's advice on getting screened: Undetected cancer that's advanced is harder to treat, and colon cancer can have these dangerous effects. Read on to find out more—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.



Woman anemia

A common symptom of colon cancer is rectal bleeding or blood in the stool, says the Mayo Clinic. Internal bleeding of this kind can cause anemia, in which the body doesn't make enough red blood cells. That can cause symptoms such as fatigue, easy bruising, and paleness. If a routine blood test shows you're anemic, ask your doctor if screening for colon cancer is warranted, particularly if you're male. 


Unexplained Weight Loss

weight loss

Losing weight without trying is a common sign of several cancers, including colon cancer. It happens when cancer cells hijack the body's metabolism to promote its own growth. If you're dropping pounds without having changed your diet or exercise routine, it's worth giving your healthcare provider a call. 


Bowel Obstruction

Door knob on or off the bathroom

Although rare, experts say that colon cancer can obstruct the bowel. This can prevent stool from passing normally. It can become an emergency situation, potentially resulting in colon perforation, in which bacteria and cancer cells spread throughout the body.  


Spread Throughout the Body

Woman in her 30s sits by her living room window with a cup of tea and looks out contemplatively. She is a cancer survivor and is wearing a headscarf.

If colon cancer isn't detected early, it can become advanced, spreading to other parts of the body. Cancer is always easier to treat when it's caught in its earliest stages. This is is particularly true of colon cancer. According to the American Cancer Society, the five-year survival rate for colon cancer that has spread to distant parts of the body is 17%. For cancer that's localized to the colon, the survival rate is 90%.


Regular Screening Is Important, Starting At This Age

prostate cancer

Experts say colon cancer is largely preventable through screening. During a colonoscopy, any precancerous growths (known as polyps) can be removed before they progress to cancer. Today, the Centers for Disease Control and Prevention recommends that people begin routine colon cancer screening at age 45. In recent years, 50% fewer people have died of colon cancer because of screening. Talk to your healthcare provider if you have any concerns or questions about colon cancer. And to protect your life and the lives of others, don't visit any of these 35 Places You're Most Likely to Catch COVID.

Michael Martin
Michael Martin is a New York City-based writer and editor. Read more about Michael
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