Rectal Cancer | Baylor Scott & White Health

What is rectal cancer?

Rectal cancer is a type of cancer that starts in the lining of your rectum—the bottom part of your large intestine. It has many similarities to colon cancer, so the term colorectal cancer often refers to rectal and colon cancer together.

Like colon cancer, rectal cancer is very treatable when it’s found in the early stages. It’s also preventable with routine colorectal cancer screenings, such as a colonoscopy. During a colonoscopy, your doctor can remove pre-cancerous polyps from the rectum before they can develop into cancer.

From learning more about your rectal cancer risk to navigating a rectal cancer diagnosis, our team is by your side. With our complete network of cancer services, you have many options to guide your next steps.

Symptoms of rectal cancer

When rectal cancer first develops, you may not have any signs or symptoms. Early rectal cancer symptoms also overlap with those of several more common digestive diseases, such as hemorrhoids, irritable bowel syndrome or inflammatory bowel disease. If you’re having any ongoing digestive discomfort, a visit to the doctor is important to help get to the source of your symptoms.

As rectal cancer grows or spreads in the body, you may start to have additional symptoms, such as weight loss or fatigue. In its most advanced stages, rectal cancer may spread to other organs, causing symptoms in your lungs, bones or liver.

Some symptoms of rectal cancer include:

Rectal bleeding or blood in the stool
Constipation, diarrhea or other bowel changes
Feeling like you still need to go after a bowel movement
Narrowing of the stools
Abdominal pain or cramping
Unintended weight loss
Fatigue

What causes rectal cancer?

Rectal cancer is caused by abnormal cells in the rectum that grow rapidly. While we don’t know all the causes of rectal cancer, certain factors put you more at risk—from medical conditions to family history.

If you have any of the following risk factors, talk with your doctor about the steps to care for yourself, including a colorectal cancer screening.

Age: Generally, your risk of rectal cancer gets higher as you get older. However, cases in adults under 50 have increased in recent years.
Gender: Men have a slightly higher risk of rectal cancer than women.
Race and ethnicity: Rectal cancer rates are highest in African Americans. Other groups with a higher risk include American Indians, Alaska Natives and Ashkenazi Jews.
Family health history: If you have a family history of colorectal cancer or colorectal polyps, your risk of rectal cancer is higher. Some inherited genetic syndromes also increase your risk, such as Lynch syndrome or familial adenomatous polyposis (FAP).
Certain health conditions: If you’ve been diagnosed with inflammatory bowel disease, including Crohn’s disease or ulcerative colitis, you’re more at risk for rectal cancer.
Smoking: As with many types of cancer, smoking and tobacco use are linked to a higher risk of developing rectal cancer.
Diet: A diet high in fat, red or processed meats and excessive alcohol use can increase your risk of rectal cancer.

Rectal cancer diagnosis

Rectal cancer may be found during routine rectal examination or as a result of testing when you’re experiencing unusual or uncomfortable digestive symptoms. If you have signs of rectal cancer, your care team has many tools and technologies to find the source of your symptoms.

With rectal cancer, early diagnosis is key. When this type of cancer is diagnosed in its earliest stages, your care team may be able to surgically remove all the cancer without the need for other treatments.

Medical history, family history and physical exam

If you have any symptoms of rectal cancer, your doctor will start by asking you questions about your medical and family history and completing a physical exam. Your physical exam may include a rectal exam with a gloved finger, where your doctor checks for any lumps that can be felt in the rectum.

Endoscopic procedures

During an endoscopic procedure, your care team uses a thin tube with a light and camera to get a closer look at the inside of your rectum. The two main endoscopy procedures used to diagnose rectal cancer are colonoscopy and sigmoidoscopy.

Colonoscopy: A colonoscopy provides a view of the inside of the entire colon and rectum. It also allows your doctor to take samples of polyps or tissue in the rectum and send them to the lab to help with a diagnosis.
Sigmoidoscopy: This endoscopic procedure is similar to a colonoscopy, but instead of viewing the entire colon, your care team only looks at the lower portion of the colon. A sigmoidoscopy also may require taking tissue samples for testing.

Stool tests

Stool tests look for signs of blood or DNA in your stool that might be a sign of colorectal cancer or polyps in the colon or rectum. Usually, these tests are completed from the comfort of your home, allowing you to collect stool samples when it’s convenient for you. If stool tests are positive, they’re usually followed by a colonoscopy.

Guaiac-based fecal occult blood test (gFOBT): Fecal occult blood testing looks for blood in the stool and requires multiple samples to be sent to the lab. With this test, you may need to change your medications or diet.
Fecal immunochemical test (FIT): A fecal immunochemical test is an at-home test to help detect blood in the stool. With this stool test, you’ll collect multiple samples, but you don’t have to change your diet or medications.
DNA stool test: Along with checking for blood, a DNA stool test also checks for pieces of DNA in the stool that could be signs of rectal cancer.

Biopsies

If your care team finds rectal polyps or abnormal cells in the lining of the colon and rectum during a colonoscopy or sigmoidoscopy, they’ll take tissue samples for more testing, called a biopsy. These samples are examined closely under a microscope in the lab to look for pre-cancerous changes or cancerous cells.

Imaging tests

Especially after an initial diagnosis of rectal cancer, your doctor may use several types of imaging tests to help determine your rectal cancer stage. These tests may provide more detailed images of your rectum or look for signs that rectal cancer has spread to other areas of the body.

CT scan: As a screening for rectal cancer, CT imaging may be used during a CT colonoscopy, also known as a virtual colonoscopy. After a diagnosis, CT scans often help determine how much rectal cancer has spread or how well your treatment is working.
MRI: After a rectal cancer diagnosis, you may have an MRI (magnetic resonance imaging) to help with rectal cancer staging. This test uses strong magnets and radio waves to create cross-section images of your body.
PET/CT scan: This imaging test helps highlight cells in the body that might be cancerous. It’s often used to see if rectal cancer has spread to other places in the body or the lymph nodes, which helps decide the stage of the cancer.
Chest X-ray: A chest X-ray lets your care team look for signs of rectal cancer spreading to the lungs.
Angiography: During an angiography, your doctor injects dye into your arteries to provide images of your blood vessels. It’s often used to examine the blood vessels supplying blood to a tumor if bleeding heavily.
Ultrasound: Ultrasounds create images using sound waves, which are used in several ways in rectal cancer. You may have an endorectal ultrasound that takes images inside the rectum or an abdominal ultrasound to look for signs of cancer spreading to other organs. Intraoperative ultrasound is when an ultrasound is used during surgery.
Barium enema: A barium enema is a type of X-ray imaging test. During this imaging procedure, barium is inserted into the rectum to coat it and help provide a clear silhouette of the rectum and colon.

Types of rectal cancer

There are several types of rectal cancer, but most rectal cancers start in the lining of the rectum, usually as a rectal polyp. In rare cases, you can also develop other types of cancer in the rectum, such as carcinoid tumors (neuroendocrine tumors), GI stromal tumors or lymphoma.

When you’re diagnosed with rectal cancer, your type of cancer is important to guiding informed choices about your care. Your care team will partner with you to create a treatment plan based on your type, location and stage of rectal cancer.

Colorectal adenocarcinoma

Almost all cases of colorectal cancer—approximately 95%—are a type of colorectal adenocarcinoma. Adenocarcinoma starts in glands in the lining of organs, such as the lining of the rectum. Usually, this type of cancer begins as a rectal polyp (a raised area of the lining of the bowel that looks similar to a mushroom), called an adenoma, that turns into cancer. If the rectal polyp is removed, it can prevent cancer from developing.
Gastrointestinal carcinoid tumors

This type of rectal cancer begins in the neuroendocrine cells in the rectum, which are cells involved in hormone production. Gastrointestinal carcinoid tumors tend to grow slowly and are more common in other areas of the digestive system, not the rectum.
Rare types of rectal cancer
While there are several other types of rectal cancer, they are rare. Together, these types account for less than 5% of the total cases of the condition.
- Primary colorectal lymphomas: Non-Hodgkin’s lymphoma is a cancer that starts in a type of white blood cell called the lymphocytes, which is part of the immune system. While lymphoma can begin in several areas of the body, when it starts in the lymphocytes in the colon or rectum, it’s called primary colorectal lymphoma.
- Gastrointestinal stromal tumors: In rare cases, cancer forms in a type of cell in the lining of the rectum known as the interstitial cells of Cajal. Gastrointestinal stromal tumors (GIST) grow slowly, so they may not cause symptoms in the early stages.
- Rectal leiomyosarcomas: When cancer begins in the layers of smooth muscle tissue in the rectum, it’s called rectal leiomyosarcoma. This type of rectal cancer is rare, making up about 0.1% of cases.
- Rectal melanomas: While melanoma is most known as a skin cancer, it’s possible to develop melanoma in the rectum or other parts of the digestive system.
- Colorectal squamous cell carcinoma: Squamous cell carcinoma usually starts in the skin of the anus but can start in the rectum or colon, which is extremely rare, with less than 100 cases recorded. This type of cancer is usually associated with skin cancer.
- Familial adenomatous polyposis (FAP): People with familial adenomatous polyposis, a rare genetic condition, may develop hundreds of polyps in the colon and rectum. Often, these polyps begin to grow in childhood, and almost all people with FAP have polyps that eventually develop into cancer.

Rectal cancer treatment

Today, you have many options for your rectal cancer treatment. A team of specialists will work together to guide your care based on factors like your medical history, rectal cancer stage and personal preferences. Usually, the earlier you catch rectum cancer, the better options you have for treatment.

One of the most common treatments for rectal cancer is surgery to remove all the cancer or as much of it as possible. Depending on your rectal cancer stage, other treatments include chemotherapy, radiation therapy, targeted therapies and immunotherapy.

Surgery

Surgery to remove the cancer is one of the main treatment options in every stage of rectal cancer. The type of surgery you have depends on how much the cancer has spread. In many cases, our surgeons give you minimally invasive options that use smaller incisions during rectal cancer surgery for a quicker recovery.

Local excision: During the earliest stages of rectal cancer, your main treatment may be a procedure to remove the rectal polyp, called a polypectomy, or the local area of cancer in the rectum.
Transanal endoscopic microsurgery (TEM): Your care team could recommend TEM for early-stage rectal cancer located a little higher in the rectum. This procedure removes cancer without the need for an incision in your abdomen. A scope is inserted through the anus into the rectum to view the tumor, and microsurgical tools are used to remove it.
Transanal minimally invasive surgery (TAMIS): TAMIS is a minimally invasive surgical procedure to remove a tumor in early-stage rectal cancer that was developed as an alternative to TEM.
Low anterior resection (LAR): A low anterior resection removes the tumor in your rectum along with part of the rectum. Then, your surgeon can reattach the colon to the remaining rectum, called an anastomosis, to prevent the need for a colostomy. To give your rectum time to heal, you may need a temporary ileostomy with this surgery, where your surgeon connects the small intestine to an opening in the abdomen that allows stool to pass out of your body.
Proctectomy with coloanal anastomosis: Proctectomy removes all the rectum, including the rectal cancer. It’s often used in deeply invasive rectal cancers. To avoid needing a permanent colostomy, your surgeon will create a coloanal anastomosis, where a small pouch is made at the end of the colon to collect stool to replace the rectum.
Abdominoperineal resection (APR): This surgical procedure uses an incision in the abdomen and incisions around the anus to remove the rectum, anus and tissues around them. APR surgery is more common in low, larger, deeply invasive rectal cancer and requires a permanent colostomy to allow you to pass stool.
Diverting colostomy: When cancer blocks the rectum, causing you to be unable to pass stool, your care team may perform a diverting colostomy procedure. This procedure connects the end of the colon to an opening in the abdomen to allow stool to pass out of the body.

Chemotherapy

Chemotherapy is a treatment option for rectal cancer that’s most often used in stage 3 when cancer has spread to lymph nodes (the body’s defense mechanism), and stage 4, when cancer cells have spread to the liver, lungs, or other sites outside the rectum. These drugs help destroy rapidly multiplying cells in the body, including cancer cells.

Neoadjuvant chemotherapy: This term refers to chemotherapy used before surgery in rectal cancer, most often to treat any possible spread to other sites.
Adjuvant chemotherapy: This type of chemotherapy is used after surgery. The goal is to destroy any remaining cancer cells that weren’t removed by the operation and reduce the chances of cancer returning.

Radiation therapy

Several types of radiation therapy are used to treat rectal cancer, which uses high-energy beams or radiation seeds to destroy cancer. You may have radiation therapy for a few different reasons, such as shrinking a tumor before surgery in conjunction with chemotherapy, and rarely as an alternative to surgery or to relieve the symptoms of rectal cancer.

Immunotherapy

Immunotherapy is a treatment that uses your immune system to help fight rectal cancer. These drugs are used most often in advanced rectal cancer. Checkpoint inhibitors are the most common immunotherapy currently approved by the FDA for certain types of rectal cancer.

Targeted drug therapy

Monoclonal antibody therapy is a targeted therapy for rectal cancer. It uses specific proteins to help your body recognize and fight cancer cells. Targeted therapies may be used with other treatments or as another option when rectal cancer doesn’t respond to other treatments.

Rectal Cancer Symptoms, Diagnosis and Treatment

What is rectal cancer?

Symptoms of rectal cancer

What causes rectal cancer?

Genetic testing for rectal cancer

Rectal cancer diagnosis