Ask the Doctors Colon and Rectal Surgery

Ask the Doctor: Colorectal Cancer with the Colorectal Team

Colorectal Cancer Team

Colorectal cancer is a type of cancer that develops in the lower intestine, either the colon or rectum, and causes symptoms such as bowel movement changes, pain and weight loss as it progresses. It is a common cancer that is often detected through regular screening and requires physician diagnosis from specific tests. Colorectal cancer is preventable, treatable and curable through surgical and radiation treatments. Washington University School of Medicine and Siteman Cancer Center provide patients with screening, diagnoses and treatment options.

What is colorectal cancer? Is colorectal cancer the same as colon cancer?

Colorectal cancer starts in the colon or rectum as malignant (cancerous) cells develop in these regions of the lower intestine. Cancer that begins in the colon is called colon cancer, and cancer that begins in the rectum is called rectal cancer. Cancer affecting either of these regions is also called colorectal cancer.

What are the symptoms of colorectal cancer? Does it have stages?

Colorectal cancer is often asymptomatic, especially in early stages. Some patients will have changes in their bowel movements, rectal bleeding, weight loss or abdominal pain. The most common symptoms include:

  • Changes in bowel habits, such as frequent diarrhea or constipation
  • Stools that are narrower than usual
  • Blood (either bright red or very dark) in bowel movements
  • Dark green stools
  • Frequent gas pains, swelling or cramps
  • Loss of appetite
  • Losing weight without trying
  • Fatigue
  • Vomiting
  • Anemia
Colorectal cancer can cause symptoms like changes in bowel habits, gas pain, swelling or cramps

Like other cancers, colorectal cancer progresses in stages, during which symptoms may change or become more severe. Stages include:

  • Stage 0 (carcinoma in situ): Cancer is confined to the inner lining of the colon or rectum, usually appearing as polyps that can be removed during a colonoscopy. Stage 0 patients sometimes don’t require additional treatment after polyp removal.
  • Stage I: Cancer progresses to the second or third layers of the colon or rectal wall.
  • Stage II: Cancer progresses through the outermost layer of the colon or rectal wall and possibly organs closest to the rectum but has not yet spread to any lymph nodes.
  • Stage III: Cancer impacts the lymph nodes closest to the rectum. Subsidiary tumors, or tumor deposits, may begin to form in the fat layers of the pelvis.
  • Stage IV: Cancer has spread to other organs around the body as metastatic cancer.

How common is colorectal cancer?

Colorectal cancers are the third most common type of cancer, with more than 140,000 people diagnosed each year, and the second leading cause of cancer death in the United States. The American Cancer Society estimates that in 2021, about 149,000 will be diagnosed with colorectal cancer, and 52,000 deaths will be attributed to this disease.

What causes colorectal cancer? Are there risk factors?  

The major risk factors for colorectal cancer are age, genetics and diet. Some risks for colon cancer and rectal cancer cannot be avoided.

Age, height (taller people are at higher risk), family history, inflammatory bowel disease or an inherited syndrome are out of a person’s control but contribute to likelihood for colorectal cancer to develop.

Other risk factors, including obesity or being overweight, diets high in processed meat, physical inactivity, poor diet (low calcium, vitamin D or folate), smoking and alcohol use, can be modified.

Early-onset colorectal cancer is becoming more common, so patients are encouraged to have screenings from age 45 onwards.

Is colorectal cancer curable or preventable?

“Colorectal cancer is very curable when caught in the early stages,” says Chief of Colon and Rectal Surgery Matthew Mutch, MD. “Most importantly, colorectal cancer is preventable. Risk appropriate screening is the best tool to prevent or cure colorectal cancer.”

Preventative measures include lifestyle changes, such as quitting smoking or drinking, reducing red meat, increasing activity and nutrient intake and attending regular screening. Polyp removal and combination hormone replacement therapy may also be preventative treatments directed by a physician based on a patient’s risk factors.

How is colorectal cancer diagnosed?

Colorectal cancer is formally diagnosed through a biopsy procedure. A biopsy usually takes place during a screening test, such as a colonoscopy. Tissue samples are collected, or biopsied, during the procedure and sent to a pathologist who will examine them under a microscope. If the pathologist locates cancerous cells in the tissue sample, the patient will be diagnosed with colon or rectal cancer.

Further diagnostic tests will be necessary to determine the stage of cancer. Genetic sequencing, blood tests, CT and MRI scans, and ultrasounds may be necessary to identify the stage of cancer. The tests a patient receives depends on whether their cancer is located in the colon or rectum, because colon and rectal cancers are staged differently. Because rectal tumors have a greater capacity to impact other organs and parts of the body, they more often require additional tests.

Screening and diagnosing colorectal cancer often involves scans, such as CT or MRI scans

What is colorectal cancer screening?

Screening for cancer helps doctors detect cancer in its early stages. Cancer is more treatable in its early stages. Late-stage cancer usually requires more intense treatment. There are five screening tests to detect the presence of colorectal cancer:

  • Digital rectal exam: The doctor gently inserts a gloved, lubricated finger into the rectum and feels for abnormal areas and polyps.
  • Fecal occult blood test: Stool samples are tested for blood not visible to the eye. Blood can be a sign of polyps, other benign conditions or cancer.
  • Sigmoidoscopy: The doctor inserts a small, flexible and lighted tube into the rectum and lower colon to inspect up to 25 inches of the lower intestine. Polyps can also be removed during this exam.
  • Colonoscopy: The doctor inspects the entire colon with an instrument similar to a sigmoidoscope, but longer. Any polyps or suspicious growths can be removed during this exam. This is the standard for colorectal cancer screening, because it is the best test available to detect small and large polyps and cancers.

Barium enema with air contrast examination: For this exam, barium sulfate, a chalky substance that shows up on X-rays, is administered via enema. X-rays are then taken of the colon. To make small tumors easier to see, the doctor may carefully pump in air to expand the colon.

Colorectal cancer screening saves lives. When detected early, colorectal cancer is treatable and curable with surgery. The U.S. Preventive Services Task Force officially recommends getting screened for colorectal cancer at age 45, rather than 50.

How is colorectal cancer treated?

Colorectal cancer is best treated through surgery (often minimally invasive) and radiation therapy.

For colon cancer, the first treatment is typically surgery to remove tumors or lymph nodes associated with the affected segment of the colon. Depending on the stage of cancer, some patients will also receive systemic therapies, such as chemotherapy or immunotherapy.

For rectal cancer, Washington University Colon and Rectal has pioneered surgical techniques that allow most patients to be treated successfully without a colostomy. Even colorectal cancer that has spread to other organs can be treated surgically.

Washington University colon and rectal surgeons are also experts in minimally invasive laparoscopic surgery for colorectal cancer, which uses smaller incisions than traditional open surgery and usually leads to fewer complications, a shorter hospital stay and a faster recovery.

Colorectal Cancer Treatment at Washington University

Siteman Cancer Center, bird's eye view
Siteman Cancer Center is a leading site for colorectal cancer treatment

Washington University colon and rectal surgeons provide the highest level of care for patients with colorectal cancer. As internationally recognized leaders in the field, Washington University Colon and Rectal partners with Siteman Cancer Center to treat about 350 new colorectal cancer patients each year.

Washington University Colon and Rectal offers screening, care options and treatments for patients with colorectal cancer. Colorectal surgeons are based in Barnes-Jewish Hospital, Barnes-Jewish West County Hospital, the Center for Advanced Medicine – South County and Siteman Cancer Center and Christian Hospital. They also provide consultation with gender-specific physicians to guarantee the comfort of patients during this sensitive treatment process.

Washington University colon and rectal surgeons are part of a multidisciplinary team including medical oncologists, radiation oncologists and other specialists. The team offers personalized treatment plans based on the patient’s needs. Our approach promotes collaboration to find the best solutions for patients and often reduces the number of necessary appointments. The colon and rectal surgery team also includes skilled staff nurses, ostomy nurses, nurse practitioners and medical assistants.

Contact Us

Siteman Cancer Center has an online tool that helps patients assess their cancer risk and suggest ways to lower it. It’s available at

To learn more about the Colorectal Cancer Screening Program at Siteman Cancer Center, please call 314-747-3046 or visit the Siteman Cancer Center website.

To make an appointment with a Washington University colorectal surgeon, please call 314-454-7177 or visit the Colon and Rectal Surgery website.