Home > Medical Reference > Patient Education

Services at the UM Medical Center

See a complete list of Specialty Services and Departments at UMMC.

Colon and rectal cancers

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of colorectal cancer.


Alternative Names

Colorectal cancer


Staging

A diagnosis of cancer will lead to staging and other tests to help determine the outlook and the appropriate treatments.

Structure of the colon
The large intestine is a long hollow organ lined with mucous membrane (mucosa). Muscle layers wrap around the entire length and help move food material through to the rectum.

Staging

Unlike many other cancers, the size of the tumor is not a major factor in determining the outcome of colorectal cancer. Of greater importance is how far the cancer has spread. To determine this, doctors will assign a stage to the tumor. There are several methods for staging. The older system, known as Dukes', categorizes four basic stages: A, B, C, and D. A more recent system refers to these stages as I, II, III, and IV but divides the categories slightly differently. The term "5-year survival" means that patients have lived at least 5 years since diagnosis. Most patients who live 5 years without a recurrence are considered to be cured of their disease.

Stage

Condition

5-Year Survival

A or I

Tumor superficially involves the inner lining of the intestine.

More than 90%

B or II

Tumor has penetrated through the muscle wall of the intestine but has not reached the lymph nodes.

70 - 85%

C or III

Lymph nodes are involved.

65% or below

D or IV

Tumor has spread to other organs (metastasized), usually the liver first.

5 - 9%

Tumor Markers

Researchers are continually seeking to identify tumor markers, substances (usually found in blood samples) that will assist in the diagnosis of cancer and in monitoring effects of treatment.

Carcinoembryonic Antigen (CEA). High blood levels of a protein called carcinoembryonic antigen (CEA) sometimes indicate the presence of colon cancer. Unfortunately, it is also elevated in other cancers and in some noncancerous conditions. CEA is not effective as a screening tool for healthy people, but might eventually be helpful for patients with cancer.

Defective P53 Gene. The presence of a defective p53 gene is a marker for very poor prognosis in patients with advanced colon cancer. In its normal state, the gene is important for regulation of cell growth. Testing for this abnormality, however, is not widely done because it is not clear how to use this information.

Other Tumor Markers. Other tumor markers under investigation include a protein called GLUT1, cancer antigen 19-9 (CA 19-9), matrix metalloproteinase-9 (MMP-9) RNA, HER-2/neu oncoprotein, transforming growth factor beta-1 (TGF-beta-1), and CD44.

Sentinel Node Biopsy

A technique known as a sentinel node biopsy is increasingly performed by experienced surgeons in selected patients. This procedure is used to determine if cancer has spread beyond the nodes, possibly reducing the need for complete axillary lymphadenectomies. It involves the following:

It is still not known if the sentinel node biopsy has any survival advantages compared to the standard procedures with lymph nodes removal. However, a 2002 study indicated that careful and complete removal of potentially cancerous lymph nodes is still very important for improving survival in Stage II and III patients.


A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process . A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997-2007 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
adam.com