Diagnosing Rectal Cancer

About Rectal Cancer

At Penn Medicine, patients with rectal cancer receive their care from a multidisciplinary team of nationally recognized experts in the diagnosis, treatment and research of rectal cancer.

The rectum is a 5-inch structure located at the end of the colon. The rectum is usually empty except when stool is propelled by the upper colon into the rectum just prior to a bowel movement.

Rectal cancer is cancerous tissue that grows along and invades the wall of the rectum. Rectal cancer and colon cancer are very similar and share many common features.  The difference in location creates important differences in how each is treated.   Rectal cancer, like colon cancer, may start as a polyp that becomes cancerous.

Penn Medicine’s multidisciplinary approach to cancer diagnosis and treatment provides better outcomes and gives patients access to the most advanced treatment, surgical techniques and clinical trials.

Because navigating a cancer diagnosis and treatment options can be difficult, patients who wish to connect with a cancer specialist at Penn Medicine can speak with a cancer nurse, who can help them make an appointment with the right physician.

To connect with a cancer nurse at Penn Medicine, patients should call 800-789-PENN (7366).

Read more About Rectal Cancer

Diagnosing Rectal Cancer

An accurate cancer diagnosis from trusted cancer specialists is the first step in getting personalized treatment options to treat rectal cancer.

Patients who choose Penn’s Abramson Cancer Center benefit from a multidisciplinary team of cancer specialists including gastroenterologists, radiologists, pathologists and surgeons who work together to provide a diagnosis and treatment plan custom designed for each patient with rectal cancer.

Cancer specialists at Penn Medicine are highly experienced in using the most advanced techniques for diagnosing rectal cancer and are actively researching better and more precise ways to detect rectal cancer.

Because an accurate diagnosis is a critical step in planning cancer treatment, it’s important patients know that when they come to the Abramson Cancer Center, they are taking an important step in getting the best cancer treatment.

Navigating a cancer diagnosis and treatment options can be difficult, patients who wish to connect with a cancer specialist at Penn Medicine can speak with a cancer nurse, who can help them make an appointment with the right person. Penn Medicine’s contact center has experienced cancer nurses available and ready to guide patients in finding the cancer specialist right for them.

To connect with a cancer nurse at Penn Medicine, patients should call 800-789-PENN (7366).


Screening for Rectal Cancer

A digital rectal exam is useful for detecting rectal cancers residing in the distal rectum, near the anus. In this test, the anus and lower rectum are examined. The physician or nurse inserts a lubricated, gloved finger into the lower part of the rectum to feel for lumps or anything else unusual. 

Most rectal cancer is found through a colonoscopy. During a colonoscopy, while the patient is under sedation, the physician places a thin, tube-like instrument with a light and a lens for viewing inside the rectum and colon. The scope also has a tool to remove polyps or tissue samples, which are checked for cancer in a lab.

Colonoscopies are recommended for men and women over the age of 50 as a standard preventive test. People at high risk for colon and rectal cancer or those with a family history of cancer should talk with their physicians about recommendations for screening.

Diagnostic Tools for Rectal Cancer

If physicians suspect rectal cancer, they might perform or order one or more of these tests to diagnosis and stage rectal cancer.

  • Medical history and physical exam. An exam of the body to check general signs of health, including checking for signs of disease, and anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments is also taken.
  • Digital rectal exam. The anus and rectum are examined by a physician or nurse inserting a lubricated, gloved finger into the lower part of the rectum to feel for abnormalities.
  • Colonoscopy. Most rectal cancer is found through a colonoscopy. A colonoscopy is a procedure done while a patient is under sedation. The physician places a thin, tube-like instrument with a light and a lens for viewing inside the rectum and colon. The scope has a tool to remove polyps or tissue samples which are checked for cancer in a lab.
  • Imaging tests. Pictures of the inside of the body can help find out whether a suspicious area might be cancerous, to learn how far cancer may have spread, and to help determine if treatment is working.
    • Endoscopic ultrasound (EUS). Ultrasound uses sound waves to create a picture of the internal organs. This procedure is often done at the same time as the upper endoscopy. The endoscopic ultrasound can show enlarged lymph nodes, which may indicate a tumor or advanced disease. EUS is an important tool for staging rectal cancer.
    • Chest X-ray. An X-ray is a type of energy beam that can go through the body creating a picture of areas inside the body. If rectal cancer is found, a chest X-ray may be done to determine if the cancer has spread to the chest.
    • Computed tomography (CT) scan. A CT scan creates a three-dimensional X-ray of the inside of the body. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. A CT scan is used to see if the tumor has spread beyond the rectum to other organs. Sometimes, a contrast medium (dye) is used to provide better detail.
    • Positron emission tomography (PET) scan. A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive substance is injected into a patient’s body. The tumor absorbs the radioactive substance, and a scanner detects this substance to produce images.
    • Magnetic resonance imaging (MRI). Magnetic fields are used to create detailed images of the body. A contrast medium may be injected into a patient’s vein to create a clearer picture.
  • Biopsy. When tests find a change that is possibly cancer, a sample of the suspicious area is removed and viewed under a microscope. A biopsy is the only way to tell if cancer is really present.
  • Lab tests. A physician may order blood tests that measure the level of carcinoembryonic antigen (CEA) in the blood. CEA is released into the bloodstream from cancer and normal cells. When found in higher than normal amounts, it may be a sign of cancer.

Staging Rectal Cancer

Staging is a way of describing a cancer. Doctors use diagnostic tests to determine the cancer's stage, so staging may not be complete until all the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's chance of recovery.

Staging cancer attempts to discover:

  • The size of the tumor.
  • Whether the cancer has spread to nearby tissues and lymph nodes.
  • Whether the cancer has spread to other parts of the body.

The “staging diagnosis” for rectal cancer is as follows:

  • Stage 0. Abnormal cells are found in the innermost layer of the rectum. Also called carcinoma in situ.
  • Stage I. Cancer has formed in the innermost layer of the rectum and has spread to the next layer. Cancer may have spread to the muscle layer.  
  • Stage II. One of the following
    • IIA. Cancer has spread through the muscle layer and to the outermost layer of the rectum
    • IIB. Cancer has spread through the outermost layer of the rectum but not to nearby organs.
    • IIC. Cancer has spread through the outermost layer of the rectum and to nearby organs.
  • Stage III. One of the following:
    • IIIA.  Cancer may have spread through the two innermost layers and may have spread to the muscle layer. Cancer has spread to at least one but no more than three nearby lymph nodes or cancer cells have formed in tissues near lymph nodes. Or cancer has spread through the two innermost layers of the rectum. Cancer has spread to at least four, but no more than six nearby lymph nodes.
    • IIIB. Cancer has spread through the muscle layers to the outermost layer or has spread through the outermost layer but not to other organs. Cancer has spread to at least one but no more than three nearby lymph nodes, or cancer cells have been found in tissues near the lymph nodes. Or cancer has spread to the muscle layer of the rectum wall, or to the outermost layer. Cancer has spread to least four but no more than six nearby lymph nodes. Or, cancer has spread through the two innermost layers of the rectum and may have spread to the muscle layer. Cancer has spread to seven or more nearby lymph nodes.
    • IIIC. Cancer has spread through the outermost layer of the rectum but not to nearby organs. Cancer has spread to at least four but no more than six lymph nodes. Or, cancer has spread through the muscle layer into the outermost layer of the rectum, or has spread through the outermost layer but has not spread to nearby organs. Cancer has spread to seven or more lymph nodes. Or, cancer has spread through the outermost layer of the rectum and has spread to nearby organs. Cancer has spread to one or more lymph nodes of cancer cells have formed in the tissues near the lymph nodes.
  • Stage IV. The cancer has spread (metastasized) from where it started to lymph nodes, nearby organs and distant parts of the body.
    • IVA. Cancer may have spread through the rectum wall and to nearby organs or lymph nodes. Cancer has spread to one organ that is not near the rectum or to a distant lymph node.
    • IVB. Cancer may have spread through the rectum wall and may have spread to nearby organs or lymph nodes. Cancer has spread to more than one organ that is not near the rectum or into the lining of the abdominal wall.

Rectal Cancer Treatments

Following the diagnosis and staging of rectal cancer, cancer specialists at Penn’s Abramson Cancer Center develop a personalized treatment plan. Penn’s treatment options for rectal cancer include:

  • Surgery
    • Local excision via the anus through transanal endoscopic microsurgery (TEM) or endoscopic mucosal resection (EMR)
    • Laparoscopic, robotic-assisted or open excision
    • Pelvic exenteration (removal of other affected organs in the pelvis)
  • Radiation therapy
    • Three-dimensional conformal radiation
    • Intensity-modulated radiation therapy (IMRT)
    • Proton therapy
    • Volumetric-modulated arc therapy
  • Chemotherapy and biologic therapies
    • Chemotherapy
    • Monocolonal antibiody therapy
  • Clinical trials
    • Monoclonal antibody therapy
  • Other treatments
    • Integrative medicine and wellness
    • Palliative care
    • Penn Home Care and Hospice Services

Because navigating a cancer diagnosis and treatment options can be difficult, patients who wish to connect with a cancer specialist at Penn Medicine can speak with a cancer nurse, who can help them make an appointment with the right physician.

To connect with a cancer nurse at Penn Medicine, patients should call 800-789-PENN (7366).

Read more Rectal Cancer Treatments

Rectal Cancer Survivorship

Survivorship programs at Penn Medicine are a distinct phase of cancer care and are designed to help patients' transition from their cancer treatment routine to a post-cancer care lifestyle.

There are more than 12 million cancer survivors living and thriving today as a result of advances in cancer treatment. However, cancer treatments can result in physical, emotional and financial complications long after the therapy is complete.

Read more Rectal Cancer Survivorship


Suzi F. Garber

Suzi F. Garber, of Reading, PA., a neuroendocrine tumor patient at the Abramson Cancer Center, writes about her experience so that others might benefit from her story and become proactive advocates for themselves and their loved ones.

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