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Signs You Have Colon Cancer and Don't Even Know It

Cancer experts share what to know about colon cancer and symptoms not to ignore. 
FACT CHECKED BY Emilia Paluszek

Hearing the word "cancer" come out of your doctor's mouth is terrifying. Nobody is prepared for the diagnosis, but thanks to advancements in medicine and technology many cases today are much more treatable today.  In addition, there are ways to reduce the risk, however, the disease still remains the second leading cause of death. "Colon cancer is very common, yet preventable in most cases. Toufic Kachaamy, MD, FASGE, AGAF Interventional Program Specialist with Cancer Treatment Centers of America (CTCA), Gastroenterology and Endoscopy, tells us. "It is the third most common cancer in men and the second most common in women. Each year around 150,000 people are diagnosed in the US, and about 50,000 die from it." 

While colon cancer is common, it's a mystery in some aspects. For the last two decades, there's been a growing trend of young adults getting colon cancer and experts aren't sure why. According to the National Cancer Institute, "Since the 1990s, the rate of colorectal cancer (which includes cancers of the colon and rectum) has been rising steadily among adults younger than 50. Not only that, but more younger people are dying from the disease. This rapid increase is especially puzzling because the rate of colorectal cancer has plummeted among older adults—largely due to regular colonoscopies and lower rates of smoking."

"We don't understand a lot about the causes, the biology, or how to prevent early onset of the disease," said Phil Daschner, a program director in NCI's Division of Cancer Biology. "And that's important to learn more about because it may affect [approaches for] the treatment and survivorship of early-onset colon cancer." Yale Medicine says, "Nobody knows for sure why colorectal cancer numbers are rising in young people. Sedentary lifestyle, overweight and obesity, smoking, heavy alcohol use, low-fiber, high-fat diets or diets high in processed meats, and other environmental factors have all been associated with the disease. Family history of colorectal cancer or polyps, and conditions such as inflammatory bowel disease are also risk factors."

Not knowing you have colon cancer in the early stages is common, but there are things to watch out for and not ignore. Knowing the signs, risk factors and how to lower the chance of cancer is key to living a long healthy life and Eat This, Not That! Health spoke with cancer experts who share what to know about colon cancer and symptoms to be aware of. As always, please consult your physician for medical advice. Read on—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.


What to Know About Colon Cancer

Woman holding model of human intestines in front of body.

Jean S. Wang, MD PhD Professor of Medicine, Division of Gastroenterology, Department of Medicine, Washington University School of Medicine says, "Colon cancer is one of the most common cancers in the U.S., yet it is also one of the most preventable cancers.  Both men and women are at risk, and everyone is at risk even if you don't have a family history of colon cancer and have a healthy lifestyle.  The good news is that as long as you get the recommended screening tests starting at age 45, you can dramatically reduce your risk of dying from colon cancer."

Dr. Harvey Kaufman, a Senior Medical Director with Quest Diagnostics tells us, "The largest part of our digestive system is the large intestine or colon and it is followed by the rectum.  The colon and rectum are often considered together as the colorectum.  According to the American Cancer Society, colorectal cancer is the third most common cancer diagnosed in both men and women in the U.S. It's also the third leading cause of cancer-related deaths among men and women. Colorectal cancer is also one of the most preventable cancers, because screening can help identify at-risk individuals before cancer develops or catch cancer in its early stages, when it is more treatable than late-stage cancer."


It's Common to Have Colon Cancer and Not Know It

Gastrologist. Doctor's office. Doctor gastroenterologist with probe to perform gastroscopy and colonoscopy

Dr. Wang tells us, "Statistics show that 1 out of 20 people will get colon cancer in their lifetime.  It's very common in the early stages of colon cancer to have absolutely no symptoms.  In fact, most people who have colon cancer don't develop symptoms until the cancer has grown very large or has spread to other parts of the body.  This is why it is so important to get colon cancer screening, even if you are not having any symptoms.  Screenings can catch cancer at an early stage, before it causes symptoms, and while it is still curable." 

Tracey Childs, MD, board certified in general and colorectal surgery and chief of surgery at Providence Saint John's Health Center in Santa Monica, CA explains, "Colon cancer begins as a single rogue cell which divides into two, then four, then eight and so on. This process of developing a detectable colon cancer from that single cell can take years. The majority of colon cancers (more than 60%) in populations where medical care and screening is accessible and available occurs in patients who have no symptoms."


Warning Signs of Colon Cancer That People Often Dismiss

Young woman suffering pain at bedroom

According to Dr. Wang, "Common signs of colon cancer are rectal bleeding or blood in the stool, unintentional weight loss, feeling weak and tired all the time, constant abdominal pain or a change in bowel movements such as sudden onset of constipation.  Younger people often dismiss rectal bleeding or blood in the stool as being caused by harmless hemorrhoids.  While it is true that hemorrhoids can commonly cause bleeding, it is important to always have a colonoscopy to make sure the bleeding is not caused by colon cancer."

Dr. Kaufman says, "Colorectal cancer usually lacks symptoms until advanced disease sets in, which is why screenings are extremely important, especially when it comes to catching it early. For those with symptoms, they may notice a change in bowel health, such as increased diarrhea or constipation. Some may also feel like they're never able to fully empty their bowels. Additionally, blood in/on their stool, abdominal pain/cramps and weight loss can indicate a potential problem. If you suspect something is wrong, speak with your doctor, especially if you have a family history of cancer."


Modifiable Lifestyle Choices that Help Lower the Risk of Colon Cancer

middle-aged woman jogging in winter in a close up low angle view against a sunny blue sky in a healthy active lifestyle

Dr. Wang Explains, "There are several lifestyle choices which can help reduce the risk of colon cancer.  First of all, don't smoke!  Second, maintain a healthy weight and don't be overweight.  Exercise regularly – aim for at least 30 minutes of moderate exercise every day.  Not smoking and not being overweight are the most important things you can do to lower your risk of not only colon cancer but many other cancers as well.  Limit red meat and processed meats in your diet, since these have been shown to raise the risk of colon cancer."

Dr. Childs adds, "High fiber diet rich in fruits and vegetables and low in red meats, minimize alcohol intake, maintain healthy weight, avoid smoking, exercise, and comply with recommended health screening measures." 

Dr. Kaufman says, "Risk factors for colorectal cancer include both biological and lifestyle risks.Inflammatory bowel disease such as Crohn's disease or ulcerative colitis or a personal or family history of colorectal cancer or colorectal polyps can be a factor. These are risk factors that you can't change, but they're important to know and share with your doctor to make sure that you are getting tailored recommendations on screenings. If you have a family history of colorectal cancer, it may be recommended that you start screening at an earlier age."


Questions to Ask Your Doctor if Have Been Diagnosed with Colon Cancer

middle-aged man chatting with doctor

Dr. Wang says, "After being diagnosed with colon cancer, it is important to ask how far the cancer has spread.  You should discuss with the physician whether the cancer is confined to the colon, whether it has spread to nearby lymph nodes, or whether it has spread to other organs.  You should also ask your physician about the best course of treatment – such as whether surgery, chemotherapy, radiation therapy or a combination of the above will be the best treatment plan.  After you finish treatment, then ask your physician how often you should have a colonoscopy for follow up.   You should also ask whether your family members should start getting colonoscopy screenings at a younger age and more frequently than usual."

Dr. Kaufman states, "If you are diagnosed with colorectal cancer, there are certain points you'll want to discuss with your physician so that you can understand what the diagnosis means and what treatment options are available. The American Cancer Society has a list of questions that can help guide a discussion with your doctor. These include identifying where the cancer is located, if it's spread to other areas of the body, what stage it's in and what comes next in terms of treatment options. Discussing your family and personal health history can also help your doctor determine if there may be a need for genetic testing to help guide treatment options or identify potential gene mutations that may cause an increased risk for certain hereditary cancers."


Colon Cancer Screenings Are Vital

Doctor gastroenterologist with probe to perform gastroscopy and colonoscopy

Dr. Wang states, "Colon screenings are the most important way you can reduce your risk of dying from colon cancer. Everyone should get colon screenings starting at age 45, although if you have a family history check with your doctor as you may be recommended to start colon screenings even earlier.  There are several recommended options available for colon screenings; you only need to choose one of these options:

– colonoscopy every 10 years

– home stool test (fecal immunochemical test or FIT) every year

– home stool test (stool DNA test or Cologuard) every 3 years

Colon screenings can detect cancer early, while it is still curable.  In addition, some colon screening tests such as colonoscopy can even prevent cancer by detecting and removing precancerous polyps." 

Dr. Kaufamn emphasizes, "Something I can't stress enough is how crucial it is to follow screening guidelines. Current guidelines recommend that all adults at average risk be screened for colorectal cancer beginning at age 45 years. It's also important, even for younger people, to be informed of potential symptoms and if their family history may be putting them at a higher risk – which could indicate a need to begin screening at an earlier age.Getting the appropriate screenings and understanding your family health history are crucial for early detection and possible prevention.In general, every month of delayed cancer care can result in a10% increase in risk for mortality

Colorectal cancer usually lacks symptoms until advanced disease sets in. While some people may feel they are fine to continue to skip routine care, they should know that even short-term delays can have an impact on overall health. An additional point that people should keep in mind is that many lifesaving screenings, including colorectal cancer screenings like colonoscopies or fecal immunochemical tests (FIT) – are covered by insurance at no cost to the patient."

Heather Newgen
Heather Newgen has two decades of experience reporting and writing about health, fitness, entertainment and travel. Heather currently freelances for several publications. Read more about Heather
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