Ochsner Colorectal Cancer Screening Frequency Study Presented at American Society of Colon and Rectal Surgeons Annual Meeting

David Beck

Patients with a family history of colon cancer and a personal history of polyps should be screened with colonoscopy every 3 years, according to a new study presented at the American Society of Colon and Rectal Surgeons (ASCRS) Annual Meeting June 3–8 in Chicago. The study also concluded that patients with a family history of colon cancer who are not found to have polyps when initially screened for colon cancer should receive a follow-up colonoscopy every 5 years and that women may not need to be screened as frequently as men.

Conducted by Ochsner colorectal surgeons, the study involved 832 patients with a family history of colon cancer who underwent periodic colonoscopies from 1981 to 2001.

“What we didn't know and wanted to determine was how frequently high-risk patients should be screened for colon cancer, given that it can most effectively be treated if detected early and even prevented,” said study researcher David Beck, MD, Chairman of the Ochsner Clinic Foundation Department of Colon and Rectal Surgery.

Patients in the study were on average 59 years of age (with a range of 11 years) at baseline colonoscopy; 52% were female. The median interval for the development of adenomatous polyps was 9.3 years. Patients fell into two groups: those who had a positive baseline colonoscopy, defined as the discovery of at least one adenomatous polyp at the time of their initial screening, and those who had a negative baseline colonoscopy in which no polyps were discovered at the time of initial screening.

Two-hundred seventy-eight patients (33.4%) had positive baseline colonoscopies. These patients developed polyps in a significantly shorter period of time compared with negative baseline colonoscopy patients (p<0.0005). Three years after baseline colonoscopy, 22% had developed additional polyps; 48% after 5 years. Of the 554 patients with negative baseline colonoscopies, only 3% developed polyps after 3 years and 13% after 5 years.

Analysis of patients by gender showed that females took significantly longer to develop polyps than males (p<0.0005): 14% at 3 years and 30% at 5 years for males compared with 5% and 18%, respectively, for females. No patients developed invasive cancer during the study period.