Digital Mammography: Its Impact on Recall Rates and Cancer Detection Rates in a Small Community-Based Radiology Practice
July 21st, 2009 Posted by: admin
OBJECTIVE. The purpose of our study was to retrospectively evaluate
the impact on recall rates and cancer detection when converting from
film-screen to digital mammography in a small community-based radiology
practice.
MATERIALS AND METHODS. Audits of our institution’s records were
compiled during a 4-year period: the year before conversion to digital
mammography, and the first, second, and third years after conversion. We found
that 4,838 film-screenings were performed during the period of audit 1 without
the use of the digital system; 6,875 screenings were performed using the
digital system during audit 2; 7,379 screenings during audit 3; and 7,294
during audit 4. Cancer detection and recall rates for each of the audits were
determined retrospectively. Results were compared between audits using the
chi-square test.
RESULTS. Cancer detection rates increased from 4.1/1,000 during
film-screenings to 7.9/1,000 (p = 0.01) the year after the
introduction of digital mammography. Recall rates also increased the year
after digital mammography was introduced, from 6.1% to 10.2% (p <
0.001). Audit 3 showed no statistically significant difference in cancer
detection rates from those in audit 1, decreasing to 5.1/1,000 (p =
0.42). However, audit 4 noted an increase in the cancer detection rate to
6.9/1,000.
CONCLUSION. In this community-based mammography practice, an
increase in the cancer detection rate occurred initially during the conversion
from film-screen to digital mammography, which subsequently decreased but
remained higher than before digital conversion. This study suggests that the
new technology alone is responsible for the increased number of cancers
detected in patients with dense breasts that were not previously found using
film-screening.
