First, the good news about colorectal cancer:

The five-year survival rate is nearly 98 percent for people with colorectal cancer confined to a polyp and 94 percent for those whose cancer has invaded the superficial layers of the bowel.

Now for the not-so-good news:

The colorectal cancer survival rate plummets to 6 percent if the disease is diagnosed when it already has spread to other organs such as the liver. Once symptoms of colorectal cancer develop, such as pencil-thin stools and unexplained weight loss, the disease often is advanced and may have spread to other organs.

The lesson from these facts is simple, said Charles Lynch, M.D., Ph.D., professor of epidemiology and medical director of the State Health Registry of Iowa.

"Screening is a key to reducing the mortality rate from colorectal cancer," he said. "The American Cancer Society says screening should begin at age 50 for both men and women. People with a family history of colorectal cancer or certain colorectal diseases, such as familial polyposis, should be screened earlier."

Nearly 95 percent of all persons with colorectal cancer in Iowa are diagnosed after age 50, so if you have no increased risk factors for the disease, age 50 is a good time to start, Lynch said.

"Screening is so important because it can detect pre-malignant colorectal cancer, which takes the form of polyps," he said. "When you remove these polyps, you can prevent a person from developing colorectal cancer."

Colorectal cancer is a special emphasis in Cancer in Iowa: 2003, an annual report of cancer facts and projections issued by the State Health Registry of Iowa.

Links to the Cancer in Iowa: 2003 report are available at www.public-health.uiowa.edu/shri/pubs/pdf/Cancer_2003.pdf. Copies of the report are available by calling the State Health Registry of Iowa at 319-335-8609.

For more information about cancer, call the Cancer Information Service, part of the Holden Comprehensive Cancer Center at The University of Iowa, toll-free at 800-237-1225, or go to the UI Health Care Web site, www.uihealthcare.com/cis.

 Colorectal cancer screening takes several forms

• Fecal occult blood test every year, which involves an easy-to-use at-home kit
• Flexible sigmoidoscopy every five years, which allows examination of the area of the colon and rectum where the majority of cancers occur
• Fecal occult blood test plus flexible sigmoidoscopy every five years
• Double-contrast barium enema every five to 10 years, which provides a radiologic visualization of the entire large bowel
• Colonoscopy every 10 years, which provides an examination of the entire large bowel