Rectal cancer

Rectal cancer vs. colon cancer

Rectal and colon cancer are often grouped together under the term “colorectal cancer” because they share some symptoms; however, they originate in different regions within the large intestine and require different treatment approaches.⁴

Rectal cancer is less common than colon cancer.⁵

Colon cancer starts in the colon, which is about five feet long and absorbs water from food waste as it moves through the intestines, while rectal cancer starts in the rectum, which is the last six inches of the large intestine.⁴

The rectum is a small, confined space, which can impact the types of surgeries that can be performed as well as the nearby organs that can be affected.^4,5

Signs and symptoms of rectal cancer

Many people with rectal cancer do not experience symptoms for years; however, as the cancer advances, symptoms often appear.⁶ Signs and symptoms of rectal cancer may include:⁷ 

• Changes in Bowel Habits: Diarrhea, constipation or more frequent need to pass stool
• Feeling of Incomplete Bowel Movements: A sense that the bowel doesn’t fully empty
• Rectal Bleeding: Bright red or dark maroon blood in the stool
  • While rectal bleeding can be a sign of rectal cancer, it is often due to other causes such as swollen veins in the rectum known as hemorrhoids. If you notice bleeding, make an appointment with your doctor or healthcare professional for evaluation.⁶
• Narrow Stool: Bowel movement that looks thinner than usual, like a pencil or string
• Abdominal Discomfort: Gas pains, bloating, cramping or general stomach pain
• Unexplained Weight Loss: Losing weight without trying
• Fatigue: Feeling unusually tired or weak
• Vomiting: In some cases, nausea and vomiting may occur.

How is rectal cancer diagnosed?

Rectal cancer is typically diagnosed through an imaging test called a colonoscopy, which allows doctors to examine the rectum. A colonoscopy uses a long, flexible tube with a camera to look for signs of cancer, and a sample of tissue may be taken for lab testing.⁸

Rectal cancer staging

Rectal cancer is typically classified in five stages: 0, 1, 2, 3 and 4. The higher numbers indicate more advanced cancer and may mean the cancer has spread to lymph nodes or distant organs, while earlier stages mean cancer is limited to the rectum.⁹

Healthcare professionals commonly use the TNM staging system to identify each stage in more detail, looking at three key factors:⁹

• T. The size of the primary tumor.
• N. Whether the cancer has spread to nearby lymph nodes.
• M. Whether the cancer has spread to other parts of the body, called metastasis.

The stages of rectal cancer are as follows:^9,10

• Stage 0-1 (localized): Cancer is only in the rectum and has not spread.
• Stage 2 (localized or locally advanced): Cancer has grown through the rectal wall or into nearby tissue but has not spread to lymph nodes.
• Stage 3 (locally advanced/regional): Cancer has spread to nearby lymph nodes but not to distant organs.
• Stage 4 (metastatic/distant): Cancer has spread to distant lymph nodes or organs, such as the liver or lungs.

Rectal cancer survival rates

People with early-stage rectal cancer have a high chance of survival.¹¹ Although, even in early stages, patients may still receive treatments such as surgery, chemotherapy, or radiation, depending on their individual situation.⁸ As the cancer grows deeper into the rectum or spreads to other parts of the body, the five-year survival rate decreases.¹¹

Data from the National Cancer Institute shows 68% of people with rectal cancer were alive five years after diagnosis. The five-year survival rates by tumor location are as follows:¹⁰

• Local: 91%
• Regional: 74%
• Distant: 17%

Risk factors of rectal cancer

A few factors can increase your risk of getting rectal cancer, including:¹²

• Age
  • The risk of rectal cancer increases with age (average age of diagnosis is 63).
  • However, rectal cancer is affecting adults at younger ages.
• Certain health conditions 
  • Inflammatory bowel diseases, such as Crohn’s disease and ulcerative colitis can increase risk.
  • Excess body weight (obesity/being overweight)
  • Type 2 diabetes
  • History of colorectal polyps
• Family history 
  • Your chance of developing rectal cancer is almost double if you have a close relative with the disease.
• Sex
  • Men are slightly more likely to develop the disease than women.
• Inherited colorectal cancer syndromes  
  • Inherited genetic syndromes like Lynch syndrome and familial adenomatous polyposis (FAP) can raise the likelihood of developing rectal cancer.
• Race
  • Black people are more likely to develop rectal cancer. 
• Lifestyle factors
  • Moderate to heavy alcohol use
  • Diets heavy in red meat or processed meats or low vegetable intake

How is rectal cancer treated?

Treatment may include surgery to remove the cancer.⁸ These surgeries can carry risks of complications that vary depending on the individual and their overall health, the location of the tumor, and the specific type of surgery.¹³ If the cancer has spread or grown larger, treatment may start with chemotherapy, radiation, or a combination of the two before determining a plan for surgery. Other treatment options may include immunotherapy, targeted therapy, and palliative care.⁸ All therapies come with their own risk factors and potential side effects.

Potential challenges with rectal cancer treatment

• Surgery can cause life-changing complications including:¹³
  • Bleeding, infection, trouble controlling bowel movements, sexual dysfunction, fertility issues, ongoing fatigue or weakness, and adhesions.
  • A temporary or permanent stoma, which is a small opening created on the surface of the body in the abdomen to allow waste from the intestines to leave the body.
  • Urinary dysfunction, including frequent or urgent urination, leaking urine, or trouble emptying the bladder.
• Radiotherapy can significantly impact quality of life, potentially leading to diarrhea, constipation, incontinence, bowel urgency, bloating, skin irritation, and fertility issues.^14,15
• Chemotherapy can also cause upset stomach (diarrhea/nausea/vomiting), low white blood cell count, and nerve issues that can cause pain, numbness, tingling, or muscle weakness.¹⁶
• Immunotherapies may cause immune-related side effects that can range from mild to life-threatening and can affect the skin, intestines, liver, endocrine system or lungs.¹⁷ Other potential side effects may include fatigue, diarrhea, rash, loss of appetite and more.^18,19
• Targeted therapy side effects can vary depending on the type of therapy used. Common side effects in some targeted therapies used for colorectal cancer may include skin or eye problems, diarrhea, fatigue, hypertension and wound-healing complications, depending on the specific treatment.^20,21
• Patients with rectal cancer can face up to 4 times higher healthcare costs than those without.²²

Prevention & early detection

Regular screenings can catch abnormal cells early before they become cancer.  Talk to your healthcare provider for more information about the right time to begin colorectal cancer screenings.²³

There is no sure way to prevent rectal cancer, but you may be able to lower your risk by:²³

• Being aware of possible symptoms
• Learning about your family medical history
• Getting regular screening tests (e.g., colonoscopy, stool tests, etc.) based on the recommendations of your healthcare provider
• Maintaining a healthy body weight and increasing physical activity 
• Not smoking
• Limiting or lowering alcohol intake
• Limiting red and processed meats
• Eating more fruits, vegetables and whole grains

Frequently asked questions