How is rectal cancer diagnosed?
To diagnose rectal cancer, your doctor will ask you about your symptoms and do routine screening tests. This may include a digital rectal exam (DRE), which involves gently inserting a gloved, lubricated index finger into the rectum to feel for any abnormalities. Additionally, your doctor may do one or more of the following tests or procedures to diagnose rectal cancer.
A colonoscopy screening test can both detect and treat colorectal polyps and detect rectal cancer. It is also crucial in determining the location of cancers when they do exist. A thin, flexible, lighted tube (colonoscope) is inserted into the colon to look at the interior walls of the rectum and the entire colon. This is done as an outpatient procedure with sedation for comfort.
A biopsy is the only way to confirm a colorectal cancer diagnosis, even if other tests suggest cancer is present. During a biopsy, your doctor removes a small tissue sample with a special instrument that’s passed through a scope. A pathologist then analyzes the sample under a microscope for signs of cancer.
This lab test screens for hidden blood in three consecutive stool samples to help diagnose rectal cancer. FOBTs can detect tiny amounts of blood that are not visible to the naked eye.
This procedure uses a flexible, lighted tube (sigmoidoscope) to look at the interior walls of the rectum and part of the colon.
This office procedure uses ultrasound sound waves to specifically define and stage some rectal cancers. The test may also be used to map the anal sphincters pre-operatively in those with fecal incontinence requiring repair.
An MRI is the best way to check how far rectal cancer has spread because it gives clear pictures of the muscles, organs, and tissues around the cancer. It can also show the lymph nodes near the rectum and the different layers of tissue in the rectal wall better than a CT scan.
What is the first step after a rectal cancer diagnosis?
After you are diagnosed with rectal cancer, your Penn Medicine care team will assess the size and location of the growth. Our rectal cancer pathologists and radiologists use their expertise to accurately stage rectal cancer. The detailed information they provide ensures that you get the most appropriate treatment based on your diagnosis.
Rectal cancer typically progresses through stages, which indicate the extent of the disease.
- Stage 0: Also known as carcinoma in situ, cancer cells are found only in the innermost lining of the rectum and have not invaded deeper tissues.
- Stage I: Cancer has grown beyond the inner lining of the rectum into deeper layers of tissue but has not spread beyond the rectum.
- Stage II: Cancer has spread through the wall of the rectum but has not reached nearby lymph nodes or distant organs.
- Stage III: Cancer has invaded nearby lymph nodes but has not spread to distant organs.
- Stage IV: Cancer has spread to distant organs, such as the liver, lungs, or bones, indicating metastatic disease.
Rectal cancer diagnostics at Penn Medicine
Penn Medicine providers who specialize in rectal cancer collaborate as a team with other specialists within Penn Medicine to provide a diagnosis you can trust and understand.
Our rectal surgeons and team members are recognized nationally and internationally for their clinical, scientific, and educational contributions. All have completed fellowship training in colon and rectal surgery and are board-certified by the American Board of Surgery and the American Board of Colon and Rectal Surgery.
Your Penn Medicine doctors use advanced diagnostic tests and tools to pinpoint the most accurate diagnosis and inform your care plan.
Rated “exceptional” by The National Cancer Institute
Penn Medicine’s Abramson Cancer Center is a world leader in cancer research, patient care, and education. Our status as a national leader in cancer care is reflected in our continuous designation as a Comprehensive Cancer Center by the National Cancer Institute (NCI) since 1973, one of 7 such centers in the United States. The ACC is also a member of the National Comprehensive Cancer Network, one of a select few cancer centers in the U.S., that are working to promote equitable access to high-quality, advanced cancer care.