The symptoms of right-sided colon cancer can be different from left-sided colon cancer. They may include bleeding, which can lead to anemia. In some cases, anemia is the first sign of the condition.

This information comes from the National Institutes of Health (NIH).

The symptoms of right- and left-sided colon cancer can differ due to the location of the cancer and where it might metastasize. Because the right side of the colon is wider than the left, it can take longer for tumors to cause noticeable symptoms.

This article discusses how symptoms of colon cancer differ between the right and left sides. It also examines the diagnosis, treatment, and outlook of colon cancer, as well as lists conditions with similar symptoms.

A surgeon performing a procedure to treat right-sided colon cancerShare on Pinterest
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The symptoms of right-sided colon cancer can include blood in the stool, anemia, and weight loss. In cases where the cancer is close to the cecum, which joins the small and large intestine together, the first symptom is often anemia from chronic blood loss.

In contrast, left-sided colon cancer symptoms include:

  • change in bowel habits
  • constipation
  • ribbon-shaped, narrow stools when the cancer is low in the rectum

The reason for this difference in symptoms is the location of the cancer.

The right side of the colon is known as the ascending colon. It pushes digesting food up the right side of the abdomen before it travels across the middle and down the left side toward the anus.

The opening in the right side of the colon is wider than on the left side. This can mean that tumors on the right side may reach a larger size before a person experiences any symptoms. Tumor growth on the right side also tends to be flat, which makes growths even less noticeable until they grow bigger.

Since the opening of the left side of the colon is narrower, cancer development makes the bowel channel smaller, which can create a partial blockage. This can lead to more obvious symptoms.

Right-sided colon cancer may metastasize to the tissue lining the pelvis and abdomen, but the left-sided type may metastasize to the liver and lungs.

Below are some of the differences between right- and left-sided colon cancer.

Point of origin

The right side of the colon connects to the cecum, which is the pouch that joins the small intestine to the large intestine. Tumors here typically grow into the space within the colon.

Conversely, the left side of the colon connects to the rectum, where waste material exits the body. This cancer tends to develop around the colon wall and encircle it.


Right-sided colon cancer may metastasize into the peritoneal region, which is the tissue that lines the pelvic and abdominal area. Metastasis refers to the process where cancerous cells spread from a primary tumor and form secondary tumors in another part of the body.

In contrast, left-sided colon cancer metastasizes to the lungs and liver.


The outlook for colon cancer depends on the type and stage of the cancer, whether it has spread, and other factors.

According to a 2018 study, if right-sided colon cancer is in stage 1 or 2, the outlook is better than early-stage cancers on the left side. But if colon cancer on the right side is in stage 3 or 4, the outlook becomes worse than that of the left side in these stages.

Because of the difference in symptoms and how long they can take to appear, people with right-sided colon cancer may get a diagnosis later than people with cancer on the left.

Older research from 2008 examined the outlook of 77,978 people with colon cancer. The median survival time of those with right-sided cancer was 78 months, while the median survival time of those with left-sided cancer was 89 months.

Doctors base a colon cancer diagnosis on the following tests:

  • physical exam
  • stool blood test
  • colonoscopy, which provides a view of the entire colon and rectum
  • biopsy, which is an analysis of tissue from the suspected cancer
  • blood tests, such as:
    • complete blood count that measures different types of blood cells
    • tumor markers, which some colon cancer cells make
    • liver enzymes
  • imaging tests, such as:

Since colon cancer may not produce symptoms until it has progressed, the American Cancer Society (ACS) recommends that people start regular screenings at age 45.

Colon cancer treatment can be local or systemic.

Local treatment

Local treatment affects the area of the colon with the tumor but not the whole body. Doctors use it more often for early-stage cancers. Below are the options:


Types of surgery include:

  • polypectomy, which is the removal of a polyp
  • local excision, which is the removal of a small cancer with a small quantity of surrounding healthy tissue
  • colectomy, which is the removal of all or part of the colon, along with nearby lymph nodes

Ablation and embolization

Sometimes when cancer metastasizes, doctors may use ablation and embolization to destroy small tumors in other parts of the body. Ablation destroys tissue a doctor targets. The types include:

  • high-energy radio waves
  • electromagnetic waves
  • alcohol injections
  • freezing

Radiation therapy

This is the use of high-energy rays to destroy cancer cells. For some colon cancers, concurrent chemotherapy makes radiation more effective.

Systemic treatment

Systemic treatment involves the use of medications that can reach cancer cells that are circulating throughout the body. Options include:

  • chemotherapy, which kills cancer cells
  • targeted therapy, which targets specific changes in cells that cause cancer
  • immunotherapy, which helps the immune system identify and destroy cancer cells

There are a number of other conditions that can cause symptoms that are similar to right-sided colon cancer. A person should speak with a doctor to get a diagnosis.


Diverticula are small pouches that form and push outward in the colon wall. Diverticulitis develops when they become inflamed. Symptoms include:

  • lower abdominal pain
  • bloating
  • diarrhea or constipation

When a blood vessel in the diverticula bursts, it can cause bleeding, which may be severe.

Inflammatory bowel disease

Inflammatory bowel disease (IBD) refers to two conditions: ulcerative colitis and Crohn’s disease. They both cause visible damage to the intestinal tract. Symptoms include:

  • bloody stools or rectal bleeding
  • weight loss
  • abdominal pain
  • persistent diarrhea
  • tiredness


Hemorrhoids are inflamed, swollen veins around the anus or lower rectum. They can be external or internal. Symptoms of the external type include:

Internal hemorrhoids can cause bleeding, which results in the appearance of bright red blood in the stools. They can also prolapse, or fall, through the anal opening.

Colon polyps

Polyps are noncancerous growths in the lining of the colon and rectum. They often do not cause symptoms, but when they do, the symptoms may include:

  • black, tarry stools due to bleeding
  • observable blood in a bowel movement
  • tiredness due to anemia

The ACS collects statistics on survival rates for different types of cancer using a measure known as a “5-year relative survival rate.” This measures how many people survive for at least 5 years after their initial diagnosis.

For colon cancers, the 5-year relative survival rates are:

  • 91% for localized tumors
  • 72% for regional tumors
  • 14% for distant tumors

Localized tumors have not spread outside the colon or rectum, while regional tumors have spread to nearby lymph nodes or other structures. Distant cancer has spread to parts of the body that are distant from the colon, such as the liver or lungs.

Right-sided colon cancer symptoms can be more subtle than those of left-sided colon cancer. They include bleeding and anemia. Often, anemia is the first symptom and occurs due to ongoing blood loss.

Because the lumen of the right side of the colon is wider than that of the left, tumors here can become large in size without producing any symptoms. For this reason, the ACS recommends regular screenings for adults over 45 years old.

If a person is concerned that they might have colon cancer, they should seek a diagnosis from a doctor as soon as possible. There are a number of other conditions that may explain the symptoms. If a person does require cancer treatment, an early diagnosis can make a significant difference to the outlook.