How to Differentiate Your Symptoms

Shared Symptoms in IBS and Colon Cancer

Many people become concerned that any digestive tract symptoms are colon cancer. Digestive symptoms are often nonspecific and can be caused by various conditions. The overlap of symptoms makes diagnosis challenging.

IBS and colon cancer have some symptoms in common, but prognoses (predicted outcomes) and management strategies for the two conditions differ. It is essential to distinguish between them to receive the correct treatment.

Symptoms caused by both IBS and colon cancer include:

• Abdominal pain
• Abdominal bloating
• Constipation
• Diarrhea
• Tenesmus (feeling the need to move the bowels when there is no stool
• Persistent bowel habit changes (in IBS, more than six months)

Differences in Symptoms

IBS

People with IBS may pass mucus with their stool that appears in or on the stool. Mucus is a yellowish-white substance that’s slippery and viscous. Mucus is common in stool, but not in amounts high enough to be visible.

IBS is diagnosed with the Rome Criteria (a set of diagnostic guidelines that classify functional digestive disorders based on symptoms). The key part of the criteria is abdominal pain that improves after a bowel movement. The pain is not constant but comes and goes. This symptom must be present to diagnose IBS.

Colon Cancer

Colon cancer causes several symptoms that are not part of IBS. Not every person with colon cancer will have all of these symptoms. These include:

• A lack of appetite
• Black or tarry stools
• Bloody stools
• Fatigue or weakness
• Feeling full all the time
• Stools that are narrow or pencil-like
• Weight loss

Differences in Causes

IBS

The causes of IBS are not well understood. There are likely many causes of IBS, and one or more could lead to IBS in an individual.

IBS is called a disorder of brain-gut interaction. The nervous and digestive systems must communicate and work together for digestive functions. In IBS, they stop communicating well, leading to symptoms.

As a result, the digestive system becomes more sensitive to stimuli such as food, emotional stress, or a foreign object, like a virus or bacteria.

Some of the potential causes of IBS include:

• A disruption in brain-gut communication
• Adverse life events (especially in early childhood)
• Prior infection in the digestive system, including small intestinal bacterial overgrowth (SIBO)
• Imbalance (dysbiosis) in the makeup of bacteria, viruses, and other microbes (the gut microbiome) living in the digestive tract
• Psychological stress

IBS is common. Some people are more likely to develop IBS than others. Risk factors for IBS include:

• A history of trauma (especially sexual trauma)
• Female sex
• Genetic factors (IBS may run in families)
• Having anxiety, depression, or post-traumatic stress disorder (PTSD)

Colon Cancer

Some causes of colon cancer are better understood than those of IBS. However, it is not known how potential causes interact, and some causes remain unknown.

Changes to genes (mutations) cause colon cancer. Sometimes, the genes are inherited and passed down from parents to children. Genes that cause colon cancer may present in these inherited conditions:

Acquired gene mutations are those that first occur in the person rather than being inherited. These may also cause colon cancer. The mutations may affect genes that control the division, growth, and death of cells. This causes some cells to grow when they shouldn’t, leading to cancer.

Some risk factors for colon cancer are changeable, while others are not. Risk factors include:

• Age (especially over 50 years)
• Diets high in red meat, charred meats, or processed meats
• Ethnicity (colon cancer rates are higher in people of American Indian, Alaska Native, and Jews of Eastern European descent—Ashkenazi Jews)
• Family history of colon cancer
• History of high-risk colon polyps (polyps can be the precursor to cancer)
• Inflammatory bowel disease (IBD)
• Low levels of vitamin D
• Moderate to heavy drinking
• Overweight or obesity
• Previous gallbladder surgery (cholecystectomy)
• Radiation treatment in the abdomen or pelvis
• Sex (males are more likely to die from colon cancer)
• Smoking cigarettes
• Type 2 diabetes

Differences in Diagnosis

IBS

IBS is diagnosed not with testing but with a set of guidelines (the Rome Criteria) based on symptoms. Testing might rule out other conditions, but it does not diagnose IBS.

IBS is when there is abdominal pain occurring at least one day of the week over three months, along with diarrhea and/or constipation.

IBS doesn’t cause physical changes to the tissues of the gut. Colonoscopy (a flexible tube with a camera and tools is inserted through the anus to examine the colon) is not recommended unless there are alarming symptoms that might indicate other conditions that need to be ruled out. IBS does not lead to other diseases.

Colon Cancer

Diagnosing colon cancer typically involves one or more tests. These may include:

Screening for colon cancer starts at age 45 for people at average risk. Screening tests for colon cancer include:

• A yearly stool test, which may either be a fecal immunochemical test (FIT) or a guaiac-based fecal occult blood test (gFOBT)
• Multitargeted stool DNA test with fecal immunochemical testing (MT-sDNA or sDNA-FIT or FIT-DNA) every three years
• Sigmoidoscopy every five years
• Virtual colonoscopy (CT imaging of the colon) every five years
• Colonoscopy every 10 years

For those at higher risk of developing colon cancer, testing is more frequent and starts at earlier ages.

Differences in Treatment

IBS

The type of IBS dictates the medications used: IBS with diarrhea (IBS-D), IBS with constipation (IBS-C), or IBS with mixed symptoms (IBS-M). Many medications are available for treating IBS, including prescription and over-the-counter (OTC) options. Surgery is not part of IBS treatment.

Managing IBS includes a variety of lifestyle changes, including:

• Avoiding trigger foods (including caffeine and alcohol)
• Increasing dietary fiber
• Getting more exercise
• Mental health treatment
• Stress management
• Trialing a diet low in types of carbohydrates called FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols)
• Peppermint oil supplements

Colon Cancer

Colon cancer treatment will depend on the stage (0 through 4) diagnosed. Healthcare providers may prescribe several therapies tailored to the stage of the cancer and the individual.

Colon cancer treatment involves surgery. Surgery includes removing the portion of the digestive system affected and/or any tumors or polyps. In cases where the cancer spreads to lymph nodes or other organs, treatment also includes radiation and/or chemotherapy.

For advanced cancers that aren’t treatable with surgery, treatment includes chemotherapy. If the liver is involved, specialized treatments target tumors in that organ.

Outlook

IBS

IBS causes significant pain and distress. It doesn’t lead to other conditions like inflammatory bowel disease (IBD) or colon cancer. Many people with IBS find a combination of treatments helpful in managing symptoms.

Colon Cancer

The prognosis for colon cancer depends heavily on the stage. More advanced stages of colon cancer are potentially fatal. The five-year relative survival rate statistics based on the stage at diagnosis are:

• Localized: 91.5%
• Regional spread: 74.6%
• Distant spread: 16.2%

People treated for colon cancer will need regular follow-up exams and tests. Cancer treatments may cause both physical and mental side effects.

The healthcare team creates a screening schedule for colon cancer recurrence. Recommended lifestyle changes lower cancer recurrence risks.

When to See a Provider 

Changes in bowel movements are a reason to consult a healthcare provider, especially if you are over age 45. Serious symptoms that need immediate investigation include:

For persistent digestive problems, a healthcare provider may refer a person to a gastroenterologist (specialist in conditions of the digestive system). The gastroenterologist will determine whether tests are needed. It’s important to seek care early and receive treatment to prevent worsening symptoms.