Men benefit more from sigmoidoscopy screening for CRC than women

Sigmoidoscopy screening has reduced the colorectal cancer (CRC) incidence and death, and these benefits tend to be more pronounced in men than in women, according to a Norway study.

Researchers conducted a randomized controlled trial involving individuals aged 50‒64 years without CRC at randomization. Participants underwent screening with once-only sigmoidoscopy, with or without one faecal immunochemical test, or no screening.

Of the 100,210 participants randomized, 98,654 were included in the intention-to-screen analyses: 20,552 in the screening group and 78,102 in the no-screening group. Participation with screening was 61.4 percent in men and 64.7 percent in women.

The 23-year cumulative CRC risk in men was 4.3 percent in the screening group and 6.0 percent in the no-screening group, corresponding to a risk difference of ‒1.7 percentage points (95 percent confidence interval [CI], ‒2.2 to ‒1.2). In women, the corresponding risks were 4.2 percent and 4.7 percent, with a risk difference of ‒0.5 percentage points (95 percent CI, ‒1.0 to ‒0.1).

For CRC death, the cumulative risk in men at 23 years was 1.4 percent in the screening group and 2.2 percent in the no-screening group, yielding a risk difference of ‒0.8 percentage points (95 percent CI, ‒1.1 to ‒0.5). In women, the corresponding risks were 1.3 percent and 1.4 percent, with a risk difference of ‒0.1 percentage points (95 percent CI, ‒0.3 to 0.1).

“The effect was strongest for rectosigmoid cancer,” the researchers said. “The addition of faecal blood testing to sigmoidoscopy did not change screening benefits.”