Symptoms and diagnosis

Diagnosing rectal cancer

Rectal cancer usually starts with the development of growths inside the colon. These growths are called polyps. Polyps found in the lowest part of the colon (the rectum) can become cancerous.

If you have early-stage rectal cancer, you might have no symptoms. If symptoms do occur, they could include:

  • Abdominal pain

  • Bleeding

  • Change in bowel habits 

  • Mucus in stool

  • Painful bowel movements

  • Shortness of breath

  • Weakness or tiredness 

  • Unexplained weight loss

Tests used to diagnose rectal cancer

This is the most reliable test for finding cancerous polyps or tissue. It involves looking at your rectum and colon with a video camera attached to a long, flexible tube. After you undergo a bowel cleansing procedure, a doctor passes the tube through your rectum and colon. 

This test uses a CT scan to view your rectum and colon after a bowel cleansing procedure.

These tests involve you providing a stool sample. Doctors examine the sample for hidden blood or altered DNA. These could be signs of polyps or cancer.

The test involves passing a thin, lighted tube through your rectum. Doctors use it to look for polyps in the portion of your colon closest to your rectum and your rectum itself. The rectum is the lowest portion of your colon where your body stores stool. Like a colonoscopy, this test requires bowel cleansing beforehand.

Tests and prevention

Screening as prevention

There are a number of known risk factors for developing rectal cancer. Older adults, African-Americans and people with a family history of colon or rectal cancer are at increased risk.

Other risk factors include:

  • Diabetes 

  • Heavy alcohol use

  • History of colon or rectal polyps

  • Inactive lifestyle

  • Inflammatory intestinal conditions, including Crohn’s disease and ulcerative colitis

  • Low-fiber, high-fat diet

  • Obesity

  • Previous abdominal radiation

  • Smoking

Having regular colonoscopy screenings is the best way to prevent and screen for rectal cancer. Doctors recommend routine colonoscopies beginning at age 50. If you have a family history of rectal or colon cancer, or other known risk factors, your doctor might suggest earlier screenings.

Treatments and research

Advanced rectal cancer treatment

Rectal cancer is slow growing and very treatable if caught early.

However, rectal cancer treatment can be complex. That’s because the rectum is located so close to other organs. UW Health | Carbone Cancer Center colorectal surgeons offer the most advanced surgical treatments for rectal cancer.


For smaller rectal cancers, your doctor might recommend removing cancerous tissue or polyps during a colonoscopy. Surgeries performed during a colonoscopy include:

During this procedure, surgeons remove cancer tissue and a small amount of healthy tissue lining the rectum.

During this procedure, surgeons remove cancerous polyps. 

Other surgical options

In cases where rectal cancers are located close to the anus, both the rectum and anus must be removed. After an abdominoperineal resection, your surgeon creates an opening in your abdomen (stoma) so waste can leave your body. 

Rectal cancers may require removal of all or part of the rectum. A proctectomy is also called a segmental resection. Proctectomy can be done through traditional open surgery or a minimally invasive laparoscopic approach. During a laparoscopic procedure, a surgeon makes small incisions in your abdomen. These incisions are used to insert a tiny camera and special surgical instruments.

Some early-stage rectal cancers can be removed using a transanal approach. During this procedure, no incisions are made in the abdomen. Instead, surgeons use the anal canal to remove rectal cancers or a portion of the rectum. 

In cases where the entire rectum is removed, surgeons might be able to connect the remaining colon directly to the anus. This helps to preserve bowel function.

Additional treatments

Many people with rectal cancer will need additional treatments before or after surgery. These include:

Medication treatments for rectal cancer include chemotherapy, targeted therapy and immunotherapy. Chemotherapy works by killing cancer cells. Targeted therapy slows cancer cell growth. Immunotherapy makes your immune system attack cancer cells.  

Radiation therapy uses radiation to kill cancer cells. 

Understanding rectal cancer

We want to prevent cancer and find better treatments. To do this, UW Carbone Cancer Center rectal cancer experts conduct laboratory research and clinical trials. 

Learn more or find a clinical trial

UW Health | Carbone Cancer Center

The experts at the UW Health | Carbone Cancer Center intimately understand every type of cancer. We will get to know you and design a treatment plan that works for you and your family.

Learn more

Meet our team

A dedicated team of experts

At the UW Health | Carbone Cancer Center, we work together to provide the exact care you need, when you need it. 

Our team includes: 

  • Colorectal surgeons

  • Digestive disease specialists

  • Genetic counselors

  • Integrative medicine physicians

  • Medical oncologists

  • Nutritionists

  • Palliative care professionals 

  • Pathologists

  • Psychologists

  • Radiation oncologists

  • Social workers

Medical oncology
Surgical oncology
Radiation oncology


How to find us

If you have rectal cancer, you will be cared for by doctors and surgeons within the UW Health | Carbone Cancer Center. The Carbone Cancer Center is designated as a Comprehensive Cancer Center by the National Cancer Institute. This is the highest designation given by the nation’s leading cancer research group. 

Patient and support services

Support you can use

Three sets of hands holding a yellow ribbon symbolizing cancer
UW Health | Carbone Cancer Center
Patient Guide

To help you feel comfortable during your stay at the UW Health | Carbone Cancer Center, we invite you to learn about our facility and the services we offer.