Suppose that 50,000 women who have never had a breast cancer diagnosis are available and willing to participate in a new screening program of computerized digital mammography. One thousand one hundred thirty-two (1132) women had a positive screening test. All of these positive women had a breast biopsy, and 136 were diagnosed with breast cancer. Of the 48,868 who screened "negative" on the test, 24 were in fact in the detectable pre-clinical phase. This was determined by following these women and observing that all 24 were diagnosed with breast cancer within one year of the screening test.
-Lead time bias makes it erroneously appear that survival is better for screened versus unscreened cases.

Question

Quizplus · Accepted Answer

Lead time bias occurs when early detection through screening appears to improve survival time without actually affecting the course of the disease, as the diagnosis is made earlier but the time of death remains unchanged.

Suppose That 50,000 Women Who Have Never Had a Breast