What Can Your Gut Tell You About Cancer?

Learn to identify and manage gastrointestinal issues to maintain overall health.

By Mia James

At the very least, gastro­intestinal (GI) symp­toms are bother­some and sometimes embarrassing. No one feels her best when she’s beset with bloating, gas, pain, diarrhea, or constipation. This discomfort and inconvenience can also be a sign of a more serious concern, making an understanding of GI issues a critical part of manag­ing your health.

It is not always easy to know when GI symptoms are likely the result of stress, something you have eaten, or a minor stomach bug and when they may signal a serious condition, such a chronic illness or cancer. You can help protect yourself by learning more about common triggers, paying attention to your symp­toms, and knowing risk factors for more-dangerous concerns.

Your Gastrointestinal Tract: What It Is and What Can Go Wrong

Your GI tract, or digestive system, is a group of organs that work together to convert food into energy and basic nutrients to feed the entire body. This article discusses concerns of the lower portion of the GI tract— the stomach, small intestine, and large intestine (or colon); however, the system actually begins at your mouth, where you take in food, and continues along your alimentary canal, a long tube com­prising the oral cavity, pharynx, and esophagus. The GI tract ends with the large intestine and anal canal, where waste is broken down and eliminated from the body. Additional organs that play a role in the digestive system include salivary glands, liver, gallbladder, and pancreas.1

Given the length of the GI tract and the many processes that take place there—from eating food, digesting it and getting nutrients to the body, eliminating waste, and everything in between— there’s unfortunately ample opportunity for things to go wrong.

Any number of things can cause an upset stom­ach or digestive complication. Diet is a common trigger: certain foods may cause discomfort (some people, for example, have a bad reaction to spicy or fried foods); too much or too little fiber in the diet can cause problems; eating large amounts of certain foods, such as dairy products, can cause upset. Additional lifestyle factors that can con­tribute to GI complications include stress, insuf­ficient exercise, certain medications, and changes in routine such as travel. Gastroenteritis, also called stomach flu, is another well-known cause of common GI issues.

GI complications related to diet and lifestyle are fairly common and tend not to be serious medical concerns. Most of us experience one or more of these on occasion, and they tend to go away with time, over-the-counter (OTC) medi­cines, or changes to diet or lifestyle. There are several other, more serious conditions affect­ing the GI tract, however—issues that may be chronic (meaning they persist for a long time or constantly recur) or life-threatening or that require aggressive treatment.

Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) involves chronic inflam­mation of the GI tract. The two types of IBD are Crohn’s disease, which may affect any part of the GI system, and ulcerative colitis, which affects the large intestine. IBD is an immune-mediated dis­order, meaning that the cells of the immune system (which nor­mally protect you from infection) mistake food, bacteria, and other materials in the intestine for foreign or invad­ing substances and mount an attack against them. This response (known as an autoimmune response) results in chronic inflammation and ulcerations in the lining of the intestines.

The symptoms of Crohn’s disease and ulcerative colitis are similar and include diarrhea, rectal bleeding, urgent need to move bowels, abdominal cramps and pain, sen­sation of incomplete evacuation, and constipation (which can lead to bowel obstruction). In addition to GI symp­toms, people with IBD might experience fever, loss of appetite, weight loss, fatigue, night sweats, and loss of normal menstrual cycle.2,3

Colon Cancer

Colon cancer, or adenocarcinoma of the colon, begins in the cells that line the large intestine. It accounts for more than 90 percent of cancers originating in the colon; other cancers, including carcinoid tumors and leiomyo­sarcoma, originate in the colon but are not referred to as colon cancer.

The symptoms of colon cancer include a change in bowel habits; blood (either bright red or very dark) in the stool; diarrhea; constipation; a feeling that the bowel does not empty all the way; stools that are narrower than usual; frequent gas pain, bloating, fullness, or cramps; weight loss for no known reason; feeling very tired; and vomiting.

Stomach (Gastric) Cancer

Gastric adenocarci­noma, the most common cancer of the stomach, starts in the cells that line the surface of the stomach. The primary risk factor associated with gastric cancer is infection with the bacterium Helicobacter pylori (H. pylori), which also causes ulcers.

Though early stomach cancer often does not cause symptoms, as the cancer grows it can cause discomfort or pain in the stomach area, difficulty swallowing, nausea and vomiting, weight loss, a feeling fullness or bloating after a small meal, vomiting of blood, or blood in the stool.4

Celiac Disease

Celiac disease is an autoimmune disease that trig­gers an abnormal immune response to foods containing gluten, a protein found in wheat, rye, and barley. This response causes damage to the small intestine, which interferes with the absorption of nutrients from food. Celiac disease runs in families.

Symptoms of celiac disease include fatigue, bone or joint pain, iron-deficiency anemia with no known cause, arthritis, bone loss or osteoporosis, depression or anxiety, tingling numbness in hands and feet, seizures, missed menstrual periods, infertility or recurrent mis­carriage, and itchy skin rash.5

For Women Only

Both men and women experience GI complications, but women tend to be more vulnerable to digestive compli­cations and discomfort. “Women tend to suffer from IBS symptoms more often,” says Ellen Stein, MD, assis­tant professor of medicine at the Johns Hopkins Hos­pital in Baltimore. “This can be constipation, diarrhea, both, or pain,” she explains. While it’s not understood exactly why this is the case, it appears that pregnancy and a woman’s hormonal cycles play a role.

The Office on Women’s Health, part of the US Department of Health and Human Services, notes that even GI issues that occur equally in men and women can affect women in unique ways. For example, women with IBD may have irregular menstrual periods, and some women with celiac disease may be at risk for infer­tility or miscarriage. Pregnancy also can cause digestive issues; heartburn caused by gastroesophageal reflux is common.6

“The most common complaints I see in women are gas and bloating and constipation—and constipation in particular with menstrual cycles and hormonal changes,” says Isabelle von Althen, MD, associate pro­fessor at Stony Brook Medicine (Stony Brook University) in New York. She explains that because IBS and other GI concerns in women may be related to hormones, women may be more vulnerable during perimenopause, the time when the body transitions toward menopause. “I see more bloating symptoms in particular at this time,” says Dr. von Althen.

Ovarian Cancer

Women experiencing GI symptoms should be particularly aware of the link between GI symptoms and ovar­ian cancer. “Ovarian cancer is a con­cern,” explains Dr. Stein, “because symptoms are similar with common digestive disorders.” Symptoms of ovar­ian cancer can include weight loss or weight gain, gas, nausea, vomiting, and loss of appetite, making it easy to understand how they can be mistaken for a GI issue. Additional non-GI symptoms include a heavy feeling in the pelvis, pain in the lower abdomen, bleeding from the vagina, abnormal periods, and unexplained back pain that gets worse.7

“Get screened for ovarian cancer with a gynecological exam and an ultrasound if you have irregular menstrual bleeding or a family history of ovarian cancer, are over 40, or if symptoms are new,” recommends Dr. Stein. She adds that in addition to ovarian cancer, other gyneco­logical issues, including ovarian cysts (small fluid-filled sacs) and uterine fibroids (noncancerous growths), can cause GI-related symptoms, making a gynecological exam a wise step for women with unresolved digestive complaints.

Emotional Impact

The burden of GI issues that are not effectively managed reaches much farther than discomfort and inconvenience. “Bloating, constipa­tion, and diarrhea wreak havoc on a patient’s life when they’re out of control,” says Dr. Stein. “You plan your life around your symptoms,” she explains, “and worry about a bad episode at any time.” Living with an uncontrolled GI issue can also be socially isolating and affect your ability to do your job, causing a seri­ous impact on your emotional well-being and putting you at risk for depression and anxiety. “You might skip social events and miss or be late for work,” Dr. Stein says.

Dr. von Althen explains that self-image concerns surrounding GI issues are especially prevalent among women. “Bloating, in par­ticular, can make women feel unat­tractive,” she says. One practical rea­son why self-image concerns with bloating might affect women more than men is that women’s clothes tend to be more form fitting, Dr. von Althen adds, which means even the slightest bloating can cause discom­fort and limit wardrobe choices.

Dr. Stein cites the emotional bur­den of GI issues as an important rea­son to seek treatment: “My goal in treating patients is to empower them to take control of symptoms and avoid planning their lives around them.” Treatment will depend on the type and severity of the disorder and may involve OTC or prescrip­tion medications, lifestyle and diet changes, and medical intervention.

When to See Your Doctor

While many digestive complaints may affect quality of life and well-being, the most serious complica­tions (such as cancer and chronic illness) can pose significant health risks. Diagnosis, however, can be tricky because these dangerous conditions tend to share symptoms with less critical issues. It is there­fore important to know the red flags for serious medical issues, as well as the risk factors, so you know when to see your doctor and get appropri­ate care.

“Irritable bowel syndrome can have the same symptoms as colon cancer,” says Dr. Stein. “If you’re over 50, get a colonoscopy.” Dr. Stein also says it’s important to be aware of symptoms such as fatigue, anemia, blood in stool, and recent onset. “These are the symptoms we most worry about,” she explains.

“Age is a concern,” concurs Dr. von Althen, when it comes to GI issues. “See your doctor if you expe­rience new symptoms when you’re over 40, are bleeding or have blood in your stool, or have unintended weight loss.” She adds that anyone with a family history of GI issues, such as Crohn’s, colon cancer, and others, should see a doctor about GI symptoms.

You may also want to see your doctor if your GI symptoms haven’t gone away with time, dietary changes, or OTC medications. Even if you are not at risk of a serious complication, medical treatment can help you manage symptoms and improve quality of life.

Diet And Lifestyle

What we eat naturally affects our digestive health, making healthy food choices and balanced eating a priority. As Dr. von Althen says, “You wouldn’t put bad gas into a good car.”

Choosing whole foods and avoid­ing processed options and main­taining a regular meal schedule will help keep your GI system func­tioning well. It’s also important to be aware of some digestive pitfalls of many fad diets, even those purported to improve digestive health. Dr. von Althen and Dr. Stein agree that con­sumers risk being swayed by claims in favor of or against certain foods or food groups, when the goal for healthy digestion is really balance and moderation.

Along with diet, stress can be a huge factor in digestive health. “Your GI tract is part of the nervous system and reacts to stress,” explains Dr. Stein. She encourages people suffering from GI complications to add stress man­agement to other treatment.

For Your Overall Health

Pain, embarrassment, and inconve­nience are certainly reason enough to talk to your doctor about managing a GI disorder. And when you consider that some serious medical condi­tions share symptoms with common digestive complaints, it makes good preventive sense to have anything unusual evaluated, particularly if you are over 40 and symptoms are new. You owe it to yourself to find effective treatment and to seek screening to rule out or address illness.


Common GI Disorders and Their Symptoms

Condition Common Symptoms
Irritable Bowel Syndrome (IBS) Abdominal pain or discomfort and changes in bowel habits, including bowel movements that occur more or less often than usual, changes in stool composition, and bowel movements that ease the discomfort
Upset Stomach (Indigestion) Feeling overly full during a meal and pain or discomfort in the epigastric area (between the lower end of the chest bone and the navel)
Gas Burping, passing gas, bloating, and abdominal pain or discomfort
Gastroesophageal Reflux Disease (GERD) Heartburn, chronic cough, wheezing, asthma, and recurrent pneumonia
Constipation Fewer than three bowel movements per week; bowel movements with stools that are hard, dry, small, and painful or difficult to pass; bloating; and pain in the abdomen

Note: This is not a complete list of GI issues. If you have symptoms involving your digestive system, abdominal region, or bowel movements, your physician can help you identify the complication.


Comfort and Progress In Community: Crohnology.com and theGIconnection.com

Social media has become an increasingly vital source of support and information in healthcare. Patients, caregivers, and providers affected by GI is­sues have joined the trend with their own dynamic and valuable online networks. Crohnology.com and theGIconnection.com are two notable examples, each with a unique purpose.

Chronology (crohnology.com) is a patient-centered information-sharing network for people with Crohn’s disease and colitis. Crohn’s patient Sean Ahrens founded the organization, with the goal of building a resource where patients can instantly share experiences and gather knowledge about specific treatments and outcomes. Chronology is global network of Crohn’s and colitis patients, who, through health-tracking tools, can share information and contribute to a growing knowledge base about living with and managing these conditions. Patients connect with others with the same disorders, learn how treatments are working for one another, and record progress. Data is tracked in ways that can help each participant, while the shared information helps others.

TheGIconnection (theGIconnection.com) is a social network that allows patients affected by GI issues to connect, learn, and support one another. Developed by OMNI Health Media (omni­healthmedia.com), a leading publisher of consumer healthcare information, including Women magazine, theGIconnection provides comprehensive overviews of disorders of the GI tract (including cancers and autoimmune and other chronic conditions), break­ing news, management tips, and, importantly, a members-only support community. Users register to join conversations in a safe and secure environment, with the guidance of expert facilitators. Social net­works can be particularly valuable for patients who don’t have access to in-person support resources, have had trouble connecting with others with similar diagnoses, and are more comfortable with the pri­vacy and convenience of an online community.


  1. The Gut. theGIconnection.com website. Available at: http://thegiconnection.com/the-gut/. Accessed October 3, 2014.
  2. Crohn’s Disease. theGIconnection.com website. Available at: http://thegiconnection.com/types-of-cancer/crohns-disease-ulcerative-colitis/. Accessed October 3, 2014.
  3. Ulcerative Colitis. theGIconnection.com website. Available at: http://thegiconnection.com/types-of-cancer/ulcerative-colitis/. Accessed October 3, 2014.
  4. Gastric Cancer. theGIconnection.com website. Available at: http://thegiconnection.com/types-of-cancer/gastric-cancer/. Accessed October 3, 2014.
  5. Celiac Disease. theGIconnection.com website. Available at: http://thegiconnection.com/types-of-cancer/celiac-disease/. Accessed October 3, 2014.
  6. Digestive Health. Office on Women’s Health website. Available at: http://www.womenshealth. gov/publications/our-publications/the-healthy-woman/digestive_health.pdf. Accessed October 3, 2014.
  7. Ovarian Cancer. MedlinePlus. Available at: http://www.nlm.nih.gov/medlineplus/ovariancan­cer.html. Accessed October 3, 2014.


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