The National Health Insurance Service (NHIS) has achieved a 24.1 percentage point reduction in deferred diagnosis rates at breast cancer screening facilities following targeted inspections of institutions with excessively high deferral rates, resulting in savings of hundreds of millions of won in additional testing costs.
The NHIS announced on the 12th that after analyzing 2024 breast cancer screening deferral rates and conducting on-site and written investigations of the top 100 facilities, the average deferral rate among surveyed institutions improved from 66.8% to 42.7%, a 24.1 percentage point decrease.
Mammography results are classified into four categories: no abnormality, benign condition, suspected cancer, and deferred diagnosis. "Deferred diagnosis" refers to cases requiring re-imaging due to interpretation difficulties or additional testing. Follow-up examinations including repeat screenings and ultrasounds generate additional national health insurance expenditures.
In 2024, approximately 4.565 million people underwent breast cancer screening, of which 500,000 (10.9%) received deferred diagnoses. While the average deferral rate was 10.9%, rates varied significantly by institution, ranging from a minimum of 1.6% to a maximum of 92.9%. Among all 3,530 facilities, 1,144 (32.4%) had deferral rates exceeding 13%.
The NHIS selected the top 100 institutions with excessively high deferral rates and conducted on-site and written investigations in September last year. Key causes identified during the investigation included excessive deferrals for dense breast tissue, inconsistent application of interpretation standards, and inadequate quality control management.
Following the investigation, deferral rates at 97 target institutions dropped from an average of 66.8% to 42.7%. This resulted in 3,155 fewer deferred cases and estimated savings of approximately 352 million won based on breast ultrasound examination costs.
One clinic saw its deferral rate plummet by 85.4 percentage points, from 94.3% to 8.9%, after reviewing lesion risk assessments for dense breast tissue and standardizing interpretation criteria.
By breast tissue type, dense breast tissue showed a deferral rate of 12.8%, higher than fatty breast tissue at 8.0%. Dense breasts contain more fibrous tissue and mammary glands, making imaging interpretation relatively more difficult. However, the NHIS emphasized that "issuing excessive deferrals solely because of dense breast tissue is not appropriate."
NHIS Chairman Chung Ki-suk said, "We have confirmed that analyzing causes and managing institutions with high deferral rates can lead to improved testing accuracy and health insurance fiscal savings," adding, "We will continue to strengthen evidence-based health screening quality management to provide screening services that the public can trust."