Rectal Cancer: The Basics

Author: Marisa Healy, BSN, RN
Last Reviewed: October 25, 2023

The rectum is part of your large intestine. It is at the end of the colon. The rectum is empty except for when you are about to have a bowel movement. Stool goes from your colon, through the rectum, and out of your body. Rectal cancer is caused by rectal cells growing out of control. As the number of cells grow, they form a tumor.

Rectal cancer that has spread from the rectum to another part of the body is called metastatic cancer.

Risks

Rectal cancer risks are:

  • History of polyps.
  • Changes in genes (called genetic mutations) such as inherited colorectal cancer syndromes (FAP, HNPCC). Inherited means passed down from your parents.
  • Ulcerative colitis or Crohn’s disease.
  • Eating foods high in fat, a lot of red meat, and not eating enough fruits and vegetables.
  • Not exercising.
  • Being overweight.

Signs of Rectal Cancer

The signs can be:

  • Red blood in your stool.
  • Having constipation and diarrhea at the same time.
  • A change in the shape of your stool.
  • Feeling like you have to have a bowel movement when you don’t have to.

Diagnosis of Rectal Cancer

When your healthcare providers think you may have rectal cancer, they will do a full exam of your body and ask you questions about your health. They also may order tests:

These tests are important, but a biopsy is the only way to know for sure if you have cancer. A biopsy:

  • Looks at a piece of the rectum for cancer cells.
  • Is used to find out the cancer type, how normal it is (grade), and if it has spread.
  • May look at samples from lymph nodes to check for cancer.

A pathology report sums up these results and is sent to your healthcare provider. This report is an important part of planning your treatment. You can ask for a copy of your report for your records.

Staging Rectal Cancer

To guide treatment, rectal cancer is "staged." This stage is based on:

  • The size of the tumor and where it is.
  • If there are cancer cells are in the lymph nodes.
  • If there are cancer cells are in other parts of your body.

Stages range from stage I (1, smallest tumors) to stage IV (4, tumors that have spread to other parts of the body, also called metastatic cancer). The stage of rectal cancer will guide your treatment plan.

Treatment

Often, these treatments are used:

  • Surgery is most often used to treat rectal cancer.
  • Radiation, the use of high-energy x-rays to kill cancer cells, can be used alone or with other treatments.
  • Chemotherapy, the use of medicine to kill cancer cells, can be used alone or with other treatments.

This article is a basic guide to rectal cancer. You can learn more about your type of rectal cancer and treatment by using the links below.

Rectal Cancer: Staging and Treatment

Surgical Procedures: Surgery and Staging for Rectal Cancer

References

American Society of Clinical Oncology (ASCO). 2022. Colorectal Cancer: Stages. Taken from https://www.cancer.net/cancer-types/colorectal-cancer/stages

National Cancer Institute (2017) Rectal cancer treatment. Retrieved 8 Nov 2017, https://www.ncbi.nlm.nih.gov/books/NBK65965/

National Comprehensive Cancer Network (NCCN). 2023. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®), Rectal Cancer; Version 5.2023. Taken from https://www.nccn.org/professionals/physician_gls/pdf/rectal.pdf

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