Spots Global Cancer Trial Database for Calcium/Vitamin D, Biomarkers & Colon Polyp Prevention

Study Description

Brief Summary: The study team has developed a set of biomarkers of risk for colon cancer; this study tests 1) whether or not calcium and/or vitamin D supplementation can favorably affect these biomarkers in persons who are at higher than average risk for colon cancer (ie, have already undergone the removal of colon growths, called adenomatous polyps, which are known to be precursors to developing colon cancer), and 2) whether effects on the biomarkers predict who will get new colon polyps or not.

Detailed Description: This study is an add-on study ('adjunct study') to a clinical trial that is already being conducted (the 'parent study'). Study participants will be composed of persons who are already participating in the parent study, "Vitamin D/Calcium Polyp Prevention Study". In the parent study, a total of 1,964 people nationally are being randomly assigned to four different treatment groups: 1) calcium supplements, 600 mg twice a day; 2) vitamin D supplements, 500 IU twice a day; 3) both the calcium and vitamin D supplements twice a day; and 4) placebo tablets twice a day. The treatment period lasts three to five years at the end of which study participants undergo a follow-up colonoscopy to look for new polyps. The parent study began about a year prior to the start of this adjunct study, thus, there are already some patients in the trial who are receiving their study 'treatments' (i.e., have been 'randomized'), but more patients will be recruited into the parent study. Depending on whether someone has already been randomized, participants of the parent study will be invited to take part in the adjunct study in one of two ways: 'Aim 1' only, or 'All Aims'. First, patients who have already been randomized will be asked to allow biopsies to be made of their rectal tissue during their 3- or 5-year follow-up colonoscopy (Aim 1). Biopsies, which will be used for our biomarker measurements, are very tiny pieces of tissue that can be examined under the microscope. Second, patients who have not yet been randomized will be invited to participate more fully (All Aims) in the adjunct study. This involves having outpatient rectal biopsies taken immediately after their first phone call, their 1-year follow-up visit, and 7 - 21 days before their 3- or 5-year follow-up colonoscopy. Finally, during their 3- or 5-year colonoscopy, biopsies will be taken from three areas of the colon: the rectum (same area as the outpatient biopsies), the sigmoid colon, and the ascending colon. From all of the biopsies taken from all of the visits and colon sites, biomarker measurements will be of normal proteins that occur in the surface cells lining the colon. Study researchers will then analyze whether calcium and/or vitamin D affect these biomarkers and whether the effects predict who gets new polyps.

Keywords

Eligibility

Minimum Age: 45 Years

Eligible Ages: ADULT, OLDER_ADULT

Sex: ALL

Healthy Volunteers: No

Locations

Contact Details

Useful links and downloads for this trial