Lay Summary
Colon cancer is a leading cause of cancer deaths. Leading guidelines recommend flexible sigmoidoscopy (FS) every 10 years as a screening option for average-risk people. One area of progress involves a method called water exchange (WE). This is useful for cancer screening. We performed a randomized controlled trial on 90 average-risk individuals aged 50-74. They were tested with 2 methods: unsedated extended FS using either WE or the standard method of gas insufflation (GAS). Both methods showed similar success in examining the whole colon. More participants were satisfied with WE than GAS. Both groups felt little pain. Our study shows that modern methods, especially using WE, are effective and safe. They may remove the need for sedation, making it easier to include in large-scale screening programs.