Colon, Rectal and Anal Cancer

Colon and rectal cancer are colorectal cancers that start in the colon or rectum. Most colorectal cancers start as a growth, or polyp, on the inner lining of the colon or rectum. Depending on the type of polyp, polyps can change into cancer over time. 

The wall of the colon and rectum is made of many layers, with colorectal cancer starting in the innermost layer and can grow through other layers. When cancer cells are in the wall, they can grow into blood vessels or lymph vessels and travel to other parts of the body.

Anal cancer is an uncommon type of cancer that occurs in the anal canal, which is a short tube at the end of your rectum. Anal cancer forms when abnormal cells grow and multiply out of control. These accumulating abnormal cells form a mass, also known as a tumor. They invade nearby tissues and can spread to other organs in your body or metastasize.

Types of colorectal cancer:

• Adenocarcinomas: These cancers start in cells that make mucus to lubricate the inside of the colon and rectum. A common type of colorectal cancer.
• Carcinoid tumors: These start from special hormone-making cells in the intestine.
  • Learn more about neuroendocrine tumors.
• Gastrointestinal stromal tumors (GISTs): Start from special cells in the wall of the colon.
• Lymphoma: Cancers of immune system cells.
• Sarcomas: Start in blood vessels, muscle layers or other connective tissues in the wall of the colon and rectum.

Symptoms of colorectal cancer include:

• A change in bowel habits.
• Blood in or on your stool (bowel movement).
• Diarrhea, constipation or feeling that the bowel does not empty all the way.
• Abdominal pain, aches or cramps that don’t go away.
• Losing weight without trying.

Talk to your doctor if you experience any concerning signs of symptoms.

Symptoms of anal cancer include:

• Bleeding from the anus or rectum
• Pain in the anus
• Anal itching
• A mass or growth in the anal canal

Talk to your doctor if you experience any concerning signs of symptoms.

Colorectal liver metastases are cancerous tumors that have spread to the liver from the colon or rectum.

Liver transplantation for colorectal metastases is part of our Colorectal Cancer Liver Metastases program. This is a personalized program that integrate a multidisciplinary team that includes oncology, surgery, radiology, hepatology, and transplantation that work together to implement this novel protocol that is offered in only a few centers in the world. 

• Ochsner Cancer Institute is a Commission on Cancer accredited cancer program. Programs with this distinction have demonstrated an uncompromising commitment to improving survival and quality of life for cancer patients by providing the highest-quality, patient-centered cancer care. Learn more at facs.org/coc
• Nationally recognized as “High Performing” for Colon Cancer Surgery by U.S. News & World Report in 2024-2025.

A colonoscopy is the gold standard for detecting colorectal cancer. 

Colorectal cancer can be detected through other screening tests, which include a flexible sigmoidoscopy or a fecal immunochemical test.

If colorectal cancer is suspected, your doctor will order a biopsy to confirm the diagnosis.

A colonoscopy is the preferred method of screening for colon cancer because it allows for both diagnosis of cancer and removal of early pre-cancerous growths (polyps). If you have a normal colonoscopy, then a repeat colonoscopy is recommended 10 years later for screening. This interval may be shorter if any polyps are detected, or you have certain risk factors.

Other approved screening tests include:

• Flexible sigmoidoscopy, or flex sig: This screening test that is similar to a colonoscopy, but it only looks at the left side of the colon. It is generally recommended that this be performed more frequently than colonoscopies and in combination with stool-based tests.
• Fecal immunochemical test, or FIT Test: There are multiple approved stool-based tests that evaluate for blood or abnormal DNA, which may indicate the presence of colorectal cancer. These tests need to be performed every one to two years.
• CT scan: A CT scan can be used to see the inside of the colon and rectum.

If CT or stool-based screening tests are used, any abnormal result is usually further investigated with a colonoscopy.

Treatment for colorectal and anal cancer can include chemotherapy, radiation therapy, targeted therapies, immunotherapy or surgery.

Ochsner's colorectal surgeons specialize in the surgical removal of malignancies of the colon, rectum and anus. They offer a range of surgical options and are nationally recognized authorities on anal and perianal tumors. 

When possible, our colorectal surgeons can perform sphincter-saving surgery for low rectal cancer. In some other cases, chemotherapy and radiotherapy are given before surgery to reduce the size of the tumor. 

Anal cancer is diagnosed by:

• Visually examining your anal canal and rectum for abnormalities
• Taking an ultrasound of your anal canal
• Removing a sample of tissue for laboratory testing

If it’s confirmed you have anal cancer, additional tests such as computerized tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) may be ordered to determine the extent of the cancer.

Anal cancer screening is not recommended for the general population, but screening tests may diagnose anal cancer early in those that are high risk. Risk factors for anal cancer include:

• Being over 50
• Having multiple sexual partners
• Engaging in receptive anal sex
• Smoking cigarettes
• Having a history of cervical, vulvar or vaginal cancer
• Having a history of human immunodeficiency virus (HIV) and human papillomavirus (HPV)
• Taking medications or having conditions that suppress your immune system, including those who have received organ transplants

If you are at higher risk, an anal pap smear is recommended for men who have sex with men, every one to two years for those who are HIV positive and every two to three years for HIV negative men. For women who are HIV positive or who have a history of cervical dysplasia, an anal pap smear is recommended.