Despite being close in proximity on the human body, anal, colon and rectal cancer are different types of cancer. They also have very different treatment strategies, symptoms and potential causes. In any type of cancer, early detection and diagnosis is important.

Dr. Stephanie Carr, colorectal surgeon at Marshfield Medical Center, provides more specifics as to the differences.

Anal cancer

Doctors can more easily detect anal cancer in the anus during an office exam. It is rare, accounting for only 4% of all gastrointestinal tract cancers. It is most seen in patients in their 60’s. It’s also more common in women.

Risk factors for anal cancer include human papillomavirus, or HPV, immunosuppression, history of anal warts and anal intercourse.

“Symptoms of anal cancer are often quite vague,” Dr. Carr said. “They can include anal pain, a mass, bleeding or incontinence.”

The treatment for most anal cancers is chemoradiation. If the tumor does not respond, surgery to remove the anus may be necessary which results in a permanent colostomy.

Colon cancer

Colon cancer is the third most common cancer for American men and women.

Rectal bleeding and painful bowel movements are the two most frequent symptoms that may indicate colon cancer, said Dr. David Lee, a Marshfield Clinic radiation oncologist.

To detect colon cancer, primary care providers often use a colonoscopy or you can use Cologuard®. Dr. Carr said that Cologuard is only for average risk patients.

“It is not approved for use in patients with a personal history of colon polyps or cancer, or patients with a family history of colon cancer,” she said.

Beginning at age 45, regardless of your family history of colon cancer, you should begin getting colonoscopies every 10 years.

“Family history plays a huge role in timing of scopes,” Dr. Carr said. “Someone with a family history starts at the age of 40 or 10 years before the first-degree family member was diagnosed; whichever is earliest.”

You can detect colon cancer with a sigmoidoscopy, which screens only part of the colon. If you choose this route, you should take the test every five years.

Risk for colon cancer

The risk for colon cancer rises as people age, but it is possible for young adults to suffer from the disease. Some genetic conditions increase risk for colon cancer.

“Lynch syndrome causes patients to have defects in DNA repair, which predisposes these patients to get more advanced, aggressive forms of colon cancer,” Lee said. “A mutation in what is known as the APC (adenomatous polyposis coli) gene also predisposes patients to colorectal cancer.”

For patients with these genetic conditions, colon and rectal screenings should begin in their 20s.

Obesity is a minor risk factor for colon cancer, Lee said. More concerning, though certainly related, is a diet high in fat and preservatives. Lee recommends a low-fat, high fiber diet and daily exercise as ways to help decrease your risk for colon cancer.

Radiation generally does not play much of a role in treating colon cancer. We treat most colon cancers with surgery and chemotherapy, Lee said. Radiation treatment may come into play if a patient has advanced colon cancer.

Rectal cancer

Rectal cancer occurs within the rectum, the last portion of the gastrointestinal tract. Endoscopy, such as a colonoscopy can detect and diagnose rectal cancer. It is more common than anal cancer, as both men and women have about a 4% risk of developing rectal cancer in their lifetime.

“There are known genetic predispositions that increase the risk of rectal cancer,” Dr. Carr said. “Other risk factors include inflammatory bowel disease, poor diet, obesity, alcohol and tobacco use.”

Symptoms include rectal bleeding, pain, a change in bowel habits and unexplained weight loss.

The treatment varies depending on the staging of the disease. A simple surgical procedure can remove small tumors. More advanced tumors may require chemotherapy and radiation followed by surgical removal of the rectum.

Colonoscopy screening

Colorectal cancer is cancer that develops in the tissues of the colon or rectum. A colonoscopy can visualize and remove a polyp, which can be the beginning of colorectal cancer. The procedure can prevent the development of most colorectal cancers.

“Colonoscopies are the best way to prevent colon and rectal cancer by removing pre-cancerous polyps,” said Dr. Carr.

Talk to your primary provider to determine your risks for anal, colon or rectal cancer or schedule a colonoscopy screening.

Download chart to summarize those differences including location, symptoms, cause and treatment options for anal, colon and rectal cancer