Calcium, Vitamin D Offer Hope for Colon Cancer

Role of Supplements Studied in Lesion Development

Taking a combination of vitamin D and calcium supplements may prevent the development of pre-cancerous colorectal polyps, according to scientists who are beginning a new, clinical trial at nine sites throughout the country.

Previous research studies have focused on screening for the presence of early cancers. However, this is one of the few prospective, randomized trials to look at preventing the development of premalignant lesions, according to Robert Bresalier, M.D., professor and chair of the Department of Gastrointestinal Medicine and Nutrition at M. D. Anderson.

Preventing lesion development

In past research studies, vitamin D and calcium each have been found to offer protection against the development of polyps in the large intestine. "We have pretty good evidence that each individually could have an impact, so it makes sense to look at both calcium and vitamin D together," Bresalier says.

Nine institutions, including M. D. Anderson, are conducting the research study, which began this spring. The study, funded by the National Institutes of Health (NIH), will involve the recruitment of 2,400 people.

The other study sites are: Dartmouth University (New Hampshire), Cleveland Clinic Foundation, University of Iowa, University of Minnesota, University of North Carolina, University of Southern California, Emory University (Georgia) and University of Colorado.

Participants in this trial must:

• Be considered at average risk for colon cancer development and have already had adenomas (polyps) recently removed
• Be men or women of any age, although most people do not develop adenomas until after age 50
• Have no strong genetic history of colon cancer

During the study, participants will:

• Take either calcium alone, vitamin D alone, a calcium/vitamin D combination or a placebo
• Complete food frequency questionnaires and other surveys
• Receive an annual colonoscopy and routine blood tests
• Receive follow-up telephone calls to determine their compliance with the program
• Receive follow-up care for three to five years

During a colonoscopy, patients are given full sedation before a flexible, lighted tube is inserted into the rectum and slowly guided into the colon. This instrument, called a colonoscope, transmits an image of the inside of the colon, so physicians can carefully examine the lining for growths. The American Cancer Society (ACS) recommends that everyone have this test every 10 years starting at age 50 to help detect colorectal cancer.

"This study will not put a big burden on patients," Bresalier says. "We've usually found good compliance with such studies."

Colon cancer facts

Although colorectal cancer is the third most common cancer in the United States, it is the second deadliest. The ACS estimates that approximately 56,730 Americans will die from the disease this year. Screening can catch changes in the colon before they become cancerous, or can find cancer in its early stages, when chances of a cure are better.

Joining the trial

For more information, please contact the M. D. Anderson Information Line at 1-800-392-1611, option 3.