Missed Diagnosis

Sigmoidoscopies miss advanced precancerous colon growths in almost two-thirds of women—a failure rate twice as high as that in men. Sigmoidoscopies evaluate only one-quarter or one-half the colon and do not allow for removal of precancerous growths.

Self-defense: Everyone age 50 and over—and women, in particular—should have regular colonoscopies to screen for colon cancer. Many insurers will cover only sigmoidoscopies—colonoscopy is more expensive ($500 or more, depending on location) and requires use of a sedative.