Man with abdominal discomfort wondering about IBS vs. colon cancer

IBS vs. colon cancer: the differences

Medically reviewed on February 18, 2022 by Jordan Stachel, M.S., RDN, CPT. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.


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Stomach pain, bloating, and trouble with bowel movements can put you on high alert. They’re often indicators that something isn’t quite right—but what? Both irritable bowel syndrome (IBS) and colorectal cancers are possible culprits, but they’re sometimes confused because of their similar symptoms.

The main difference? While both may result in abdominal discomfort, colon cancer is often accompanied by fatigue, bloody stool, and/or unexplained weight loss as well. But there’s more to it than just that.

Before jumping to conclusions about your health or the health of someone you know, start by doing some research. Here we’ve compiled a detailed outline of these two conditions so that you can identify possible symptoms, how they are commonly diagnosed, and what may be involved along the pathway to recovery.

Symptoms of IBS

IBS is a chronic gastrointestinal disorder that causes abdominal discomfort during flare-ups. It’s estimated that somewhere between 9 to 23 percent of the world’s population may suffer from some degree of IBS [1]. The severity of symptoms varies widely. For most, IBS symptoms include one or more of the following:

  • Diarrhea
  • Constipation
  • Bloating
  • Abdominal pain
  • Gas
  • Mucus in the stool

Some people also are left with a feeling that their bowel movement is incomplete.

While all these symptoms are painful and uncomfortable, IBS doesn’t cause damage to the digestive system. Researchers don’t know the exact cause of IBS but, in many patients, the symptoms are exacerbated by:

  • Stress
  • Certain foods
  • Menstruation
If any of these IBS symptoms sound familiar and are raising concerns about health, it may be time to reach out to a healthcare professional.

Symptoms of colon cancer

So, what is colon cancer and how does it differ from IBS? Like IBS, abdominal pain and discomfort are colon cancer symptoms. However, colorectal cancers don’t often produce any symptoms until the cancer has progressed [2]. This is why it’s critical to screen for colon cancer regularly and as directed by your healthcare provider. Possible symptoms of colon cancer can include:

  • Changes in bowel habits
  • Feeling an incomplete bowel movement
  • Rectal bleeding or blood in the stool
  • Cramps or stomach pain
  • Fatigue
  • Sudden, inexplicable weight loss

The final symptoms on this list (fatigue and unexplained weight loss) are what set colon cancer apart from IBS.

Blood in the stool, as well, tends to be more common amongst patients with colon cancer rather than IBS. This might be difficult to spot with the naked eye. However, if the stool is darker than usual, this might be the result of blood leaking from polyps in the colon. Polyps, a frequent indicator of colon cancer, are small cell masses that can become cancerous.

What are the key differences between IBS and colon cancer?

When it comes to IBS and colon cancer, the largest distinguishing factor is the severity of the condition. IBS is painful and can lead to a lower quality of life if the symptoms are severe. However, it isn’t a deadly disease.

Colorectal cancers, on the other hand, are one of the most diagnosed cancers in the United States. They’re also the third leading cause of cancer-related deaths [3]. The good news is that colon cancer is highly treatable when it’s caught early. The more it progresses, the more deadly it becomes.

Even having a mild symptom can indicate something is wrong. If you think something might be off, take control of your health and peace of mind by making an appointment with a healthcare provider.

How is IBS diagnosed?

An IBS diagnosis typically involves a visit to your healthcare provider's office [4]. Here, you can expect to do several things, including:

  • Answer screening questions – questions about your family’s medical history, your symptoms, medications, diet, and recent stress levels will be posed. These will help your healthcare provider assess potential triggers of pain and discomfort.
  • Undergo a physical exam – a brief physical exam to check for abdominal soreness or bloating will take place.
  • Submit further tests, if needed – If warranted, further testing may be advised. Often stool or blood tests are ordered to check for any signs of infection, blood, or other problems.

The information gathered during these assessments is usually enough to give your healthcare provider an indication of IBS and not colon cancer.

How is colon cancer diagnosed?

Most people begin screening for colon cancer when they turn 50 years old. If there is a family history or other increased risk factors, however, screening should begin at 45.[5]

Colorectal cancers are diagnosed using one or more of the following tests:

  • Fecal occult blood test – Fecal occult blood tests are used to check the stool for blood. Often, blood in the stool isn’t visible without a microscope. So, testing the stool is the only way to know for sure if blood is present. Blood can be an indicator of cancer or polyps that haven’t turned cancerous, so additional testing may be needed.
  • Colonoscopy – A colonoscopy is probably the procedure most often associated with colon cancer screening. It involves inserting a tiny camera, or colonoscope, through the rectum and into the colon. This allows a healthcare professional to view the colon and take samples of tissue if needed.
  • Sigmoidoscopy – A sigmoidoscopy is like a colonoscopy. It involves inserting a sigmoidoscope into the rectum so that a healthcare provider can view the inside of the colon. The only difference is a sigmoidoscopy looks solely at the lower colon. A colonoscopy is slightly more invasive, and more thorough, as it looks at the entire colon.
  • Virtual colonoscopy – A virtual colonoscopy uses a series of x-rays to take pictures of the colon. This method will show if there are any polyps or other unusual growths on the inside of the colon.
  • DNA stool tests – A DNA stool test checks the stool for changes in DNA that may indicate colon cancer. Further testing is usually needed for confirmation if altered DNA is found.

A healthcare provider will help determine the best colorectal cancer screening tool for you, depending on your risk factor profile. Although blood in the stool can be linked to colon cancer, it can also be linked to hemorrhoids. Learn the difference between hemorrhoids and colon cancer on our blog.

How are IBS and colon cancer treated?

As you can imagine, treatments for IBS and colon cancer are quite different. If you’re diagnosed with colon cancer, you may have a longer, more intense road to recovery. IBS treatments, on the other hand, center on managing the discomfort and flare-ups it causes.

IBS treatments

Treating IBS typically involves one or a combination of the following to mitigate the pain associated with the disorder [6]:

  • Dietary changes – Many sufferers find relief when they eliminate certain foods from their diet. Gluten, lactose, and other common irritants can cause IBS to flare up. Adding more fiber to the diet may also help relieve some of the discomfort of IBS.
  • Lifestyle changes – Periods of high stress can also trigger IBS. Managing stress through exercise, meditation, and other strategies can help IBS patients get their symptoms under control.
  • Medication – Over the counter and prescription medications might be necessary if dietary and lifestyle changes don’t work. Laxatives might be used for constipation while prescription-strength medicines may assist with severe symptoms.

Everyone’s body responds to these changes differently, so the appropriate mix of treatment options will depend on each specific case.

Colon cancer treatments

Colorectal cancers are classified into five stages, based on three key factors:[7]

  • The size of the tumor
  • If the tumor has spread to the lymph nodes nearby
  • If the tumor has spread to distant sites, or metastasized

The available colon cancer treatments vary depending on the stage the cancer is in when it’s detected.

  • Stage 0 – Stage 0 is when cancer is in the earliest stages. At this point, surgery is the best option. It allows a healthcare provider to remove the growth before it progresses or spreads.
  • Stage I – At stage I, cancer has grown through the mucus membranes in the colon but hasn’t spread to the lymph nodes or elsewhere. Surgery tends to be the best treatment option at stage I, as well.
  • Stage II – Once cancer has grown through the wall of the colon or rectum it’s reached stage II. At this point, there still isn’t any spread to the lymph nodes or other organs. Surgery may be needed to remove the cancerous cells.
  • Stage III – Once cancer reaches stage III, it has spread to between 4 and 6 nearby lymph nodes. However, it hasn’t reached any other sites. Surgery still may be the best option. In some cases, surgery will be followed by chemotherapy
  • Stage IV – Stage IV is the most serious stage. Within stage IV are several degrees of severity. Cancer has spread to another organ and/or distant lymph nodes. Surgery, radiation, and chemotherapy are all possible treatments for stage IV colon cancer. Other options may be available to manage comfort and quality of life.

While a cancer diagnosis is always scary, colorectal cancers are highly treatable if caught early on. If you are looking for ways to keep your colon healthy, regular screening is one of the best ways to stay on top of your health.

Monitor your health and get peace of mind with Everlywell

Since many of the symptoms of IBS and colon cancer are similar, it can be challenging to know what’s at the root of the discomfort without further testing. Testing may help provide deeper insight.

If you want a noninvasive option to screen for colon cancer, the Everlywell Colon Cancer Screening Test can help. This test is for those over the age of 45 and will provide you with results in just days. This way, you’ll be prepared with the information you need to contact your health professional and to take the necessary steps forward toward a healthier you.

IBS vs. Celiac Disease vs. Gluten Sensitivity: Understanding the Differences

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What foods to avoid with celiac disease

Hemorrhoids vs. Colon Cancer: What are the differences?


References

1. Saha L. Irritable bowel syndrome: Pathogenesis, diagnosis, treatment, and evidence-based medicine. World Journal of Gastroenterology. 2014;20(22):6759. doi:10.3748/wjg.v20.i22.6759. Accessed February 18, 2022.

2. Mayo Clinic. Colon cancer - Symptoms and causes. Mayo Clinic. Published 2018. URL. Accessed February 18, 2022.

3. American Cancer Society. Key Statistics for Colorectal Cancer. Cancer.org. Published 2019. URL. Accessed February 18, 2022.

4. Saha L. Irritable bowel syndrome: Pathogenesis, diagnosis, treatment, and evidence-based medicine. World Journal of Gastroenterology. 2014;20(22):6759. doi:10.3748/wjg.v20.i22.6759. Accessed February 18, 2022.

5. ACS announces new guideline for colorectal cancer screening for adults at average risk - Mayo Clinic. www.mayoclinic.org. Accessed February 16, 2022. URL. Accessed February 18, 2022.

6. The role of lifestyle-related treatments for IBS - Mayo Clinic. URL. Accessed February 18, 2022.

7. Mayo Clinic. Colon cancer - Diagnosis and treatment - Mayo Clinic. Mayoclinic.org. Published 2018. URL. Accessed February 18, 2022.

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