Part 6/11:
Another facet of the illusion involves when survival time is measured. Since survival is typically counted from the date of diagnosis, earlier detection automatically boosts survival statistics, even if the cancer’s course isn’t altered.
For instance:
Jennifer feels a lump at age 50 in 1970 and dies at 55—her survival time is 5 years.
In 1990, with screening, her cancer is detected at age 48, even though her biology remains the same. She still dies at 55, but her recorded survival time since diagnosis is now 7 years. The clock started earlier, inflating survival statistics without any real gain in longevity.