Fecal immunochemical test (FIT) kits were sent to around 700,000 people, who participated in the Kaiser Permanente Northern and Southern California health plans, in 2007 and 2008.

According to Douglas A. Corley, MD, PhD, of the Kaiser Permanente Division of Research, in Oakland, and colleagues, these participants (between 50-70 years of age) had not undergone colonoscopy in last 10 years, a sigmoidoscopy in last five years or a fecal blood test during the last year.

The team received the completed kits through mail from 48% of the participants during the first year. The team then followed up with these enrollees over a course of a minimum of four subsequent annual screening rounds. The returning participants were 46% female, 55% white and 82% between the ages of 50 and 64 years. The complete kit received from 323, 349 Kaiser Permanente participants were examined and 80% of the colorectal cancer (CRC) diagnosis among them were found, with 5% positivity rate as well as positive predictive value (PPV) of 3% for colorectal cancer and 52% for adenoma.

During the second round of annual screening, participants with positive FIT results, the development of CRC, exiting of health plan and those who died, were excluded. This reduced the enrollees’ pool to 244,476, and in this round, 75% of the enrollees returned the completed kits. In the third annual round, 195, 693 participants were left and out of them, 83% responded. Finally, the fourth round saw 168,853 participants, with 86% response rate.

During the first round, CRC was detected in 645 enrollees, and in second round, it was detected in 195 participants. In the third round, 188 enrollees were diagnosed with CRC, with 164 being diagnosed in the fourth round. Annual FIT screening was associated with high sensitivity for CRC, with high adherence to annual follow-up screening among initial participants. “The findings indicate that annual programmatic FIT screening is feasible and effective for population-level CRC screening”, said the team.