(HealthDay News) — A single flexible sigmoidoscopy (FS) screening at age 55 to 64 years in adults at average risk reduces colorectal cancer (CRC) incidence and mortality, according to a study published online Nov. 9 in the Annals of Internal Medicine.
Carlo Senore, M.D., from the University Hospital Città della Salute e della Scienza in Turin, Italy, and colleagues assessed long-term outcomes of a parallel randomized controlled trial, conducted at six centers in Italy, that involved persons aged 55 to 64 years who expressed interest in having FS screening if invited.
Participants were recruited from 1995 to 1999 and followed until 2012 for incidence (median follow-up, 15.4 years) and until 2014 to 2016 for mortality (median follow-up, 18.8 years). Data were included for 34,272 persons (17,136 each in a once-only FS screening group and control group); 9,911 participants in the intervention group had screening.
The researchers found that when comparing persons screened in the intervention group with controls, there was a 19 percent reduction in incidence of CRC in the intention-to-treat (ITT) analysis and a 33 percent reduction in the per protocol (PP) analysis (rate ratios, 0.81 and 0.67, respectively). Reductions of 22 and 39 percent were seen in CRC mortality in the ITT and PP analyses (rate ratios, 0.78 and 0.61, respectively). CRC incidence was significantly reduced among men and women, while CRC mortality was significantly reduced for men but not women.
“Such strong evidence of long-lasting protection from a single FS screening would suggest the need to revise existing guidelines, which still recommend repeated FS screening,” the authors write.