Letters Section Editor: Robert M. Golub,
MD, Senior Editor.
In Reply: Dr Zahl and colleagues suggest that
as many as one third of all cancerous tumors detected by mammography screening
among women aged 50 to 69 years would not have been detected during the individual’s
lifetime without screening, and therefore represent overdiagnosis.1 They suggest further that many subclinical cancerous
tumors, invasive and noninvasive, may regress spontaneously without treatment.
They base this hypothesis on the high breast cancer detection rates in the
screened cohorts of women compared with nonscreened cohorts, the absence of
a substantial and durable decline in detection rates following screening,
and the time trends of breast cancer incidence rates that increase markedly
(as much as 50%) in the screened cohorts after initiation of population-based
mammography screening. A strong tendency of many of the tumors detected by
mammography screening to undergo apoptosis and even regress spontaneously
would be consistent with a favorable outcome of cancerous tumors of similar
size found outside of screening.
Joensuu H, Lundin J. Spontaneous Regression of Cancerous Tumors Detected by Mammography Screening—Reply. JAMA. 2004;292(21):2579-2580. doi:10.1001/jama.292.21.2580-a