Medical audit of diagnostic mammography examinations: Comparison with screening outcomes obtained concurrently

OBJECTIVE. We performed a medical audit of our diagnostic mammography pract ice and compared clinical outcomes with those of screening mammography exam inations performed concurrently. MATERIALS AND METHODS. We analyzed 46,857 consecutive mammography examinati ons (10,007 diagnostic, 36,850 screening) from 1997 to 2000. including data on demographics. image interpretation, and biopsy (including size. nodal s tatus, and cancer stage). RESULTS. The mean age at diagnostic mammography was 55.8 years (mean age at screening mammogram, 59.1 years: p < 0.0001). Among patients who underwent diagnostic examinations. 14.7% had a strong or very strong family history of breast cancer (screening, 11.6%: p < 0.0001). Examination findings were interpreted as abnormal in 14.4% (screening, 5.2%; p < 0.0001). Biopsy was performed in 11.9% (screening. 1.4%; p < 0.0001). Forty-six percent of the biopsies were positive for malignancy (screening, 38%: p < 0.0001), The can cer detection rate was 55 per 1000 (screening, 5/1000; p < 0.0001). Of canc ers found, 74.3% were stage 0 or I (screening, 89.3%; p < 0.0001), average size was 18.0 mm (screening, 12.9 mm: p < 0.0001), and axillary nodes were positive for malignancy in 19.9% of invasive cancers (screening, 6.3; p < 0 .0001), Differences between diagnostic and screening outcomes were attribut able predominantly to the subgroup of diagnostic examinations performed for evaluation of palpable masses. CONCLUSION. Medical auditing of diagnostic mammography examinations yields substantially different results compared with those of screening examinatio ns, including different patient demographics: higher number of positive bio psies; higher cancer detection rates; and larger, more advanced-stage cance rs. Diagnostic and screening data should be segregated during auditing, or if this is not possible, analysis of combined results should be based on kn own differences between diagnostic and screening outcomes.