Standardized Abnormal Interpretation and Cancer Detection Ratios to Assess Reading Volume and Reader Performance in a Breast Screening Program

PURPOSE: To determine the relationship between annual screening volume and radiologist performance in the Screening Mammography Program of British Columbia, Canada.

MATERIALS AND METHODS: Standardized abnormal interpretation ratios and standardized cancer detection ratios were constructed for 35 readers with at least 3 years of experience with the Screening Mammography Program of British Columbia. The ratios were used to compare individual reader performance with the mean program performance after adjustment for the age and screening history (first versus subsequent screening examinations) of the women who underwent screening.

RESULTS: The mean standardized abnormal interpretation ratio was better for readers of 2,000–2,999 (n = 8) and 3,000–3,999 (n = 9) screening mammograms per year than for those of less than 2,000 (n = 9) and 4,000–5,199 (n = 9) screening mammograms per year. Differences in the mean standardized abnormal interpretation ratios were significant (P < .05) between the readers of less than 2,000 and of 2,000–2,999 screening mammograms per year, between readers of less than 2,000 and of 3,000–3,999 screening mammograms per year and between readers of 3,000–3,999 and of 4,000–5,199 screening mammograms per year. The mean standardized cancer detection ratio improved gradually with increasing annual volume, but the differences between groups were not statistically significant. Five of the eight readers of 2,000–2,999 mammograms were reading 2,475 or more screening mammograms per year.

CONCLUSION: Standardized abnormal interpretation ratios and standardized cancer detection ratios provide a method of comparing two important performance measures in a screening program. A minimum of 2,500 interpretations per year is associated with lower abnormal interpretation rates and average or better cancer detection rates.

References

  • 1 U.S. Department of Health and Human Services. Small entity compliance guide: an overview of the final regulations implementing the Mammography Quality Standards Act of 1992 Rockville, Md: U.S. Department of Health and Human Services, 1997; 16-19.
  • 2 National Health Services Breast Screening Programme. Quality assurance guidelines for radiologists The Royal College of Radiologists, June 1990. Oxford, United Kingdom: Screening Publications, 1990.
  • 3 National Health Services Breast Screening Programme. Quality assurance guidelines for radiologists National Health Services Breast Screening Programme publication no. 15. Sheffield, United Kingdom: National Health Services Breast Screening Programme, 1997.
  • 4 Sickles EA. Quality assurance: how to audit your own mammography practice. Radiol Clin North Am 1992; 30:265-275.
  • 5 National Program for the Early Detection of Breast Cancer. National accreditation requirements: March 1994 Canberra, Australia: Commonwealth Department of Human Services and Health, 1994.
  • 6 Ciatto S, Del Turco MR, Giorgi D, et al. Assessment of lesions detected at mammographic screening: performance at first or repeat screening in the Florence programme. J Med Screen 1994; 1:188-192.
  • 7 Bryant HE, Desautels JEL, Castor WR, et al. Quality assurance and cancer detection rates in a provincial screening mammography program: work in progress. Radiology 1993; 188:811-816.
  • 8 Clay M, Hislop TG, Kan L, et al. Screening mammography in British Columbia: 1988–1993. Am J Surg 1994; 167:490-492.
  • 9 Otten JDM, van Dihck JAA, Peer PGM, et al. Long term breast cancer screening in Nijmegen, the Netherlands: the nine rounds from 1975–92. J Epidemiol Community Health 1996; 50:353-358.
  • 10 Fracheboud J, de Koning HJ, Beemsterboer PMM, et al. Nation-wide breast cancer screening in the Netherlands: results of initial and subsequent screening 1990-1995. Int J Cancer 1998; 75:694-698.
  • 11 Libstug AR, Moravan V, Aitken SE. Results from the Ontario breast screening program, 1990-1995. J Med Screen 1998; 5:73-80.
  • 12 Sickles EA, Ominsky SH, Sollitto RA, Galvin HB, Monticciolo DL. Medical audit of a rapid throughput mammography screening practice: methodology and results of 27,114 examinations. Radiology 1990; 175:323-327.
  • 13 Warren Burhenne LJ, Hislop TG, Burhenne HJ. The British Columbia mammography screening program: evaluation of the first 15 months. AJR Am J Roentgenol 1992; 158:45-49.
  • 14 Warren Burhenne LJ, Burhenne HJ, Kan L. Quality-oriented mass mammography screening. Radiology 1995; 194:185-188.
  • 15 Screening Mammography Program of British Columbia. Annual report, 1996/97 Vancouver, British Columbia, Canada: British Columbia Cancer Agency, 1997.
  • 16 Neter J, Wasserman W. Applied linear statistical models Homewood, Ill: Irwin, 1974.
  • 17 National Health Services Breast Screening Programme. NHS Breast Screening Programme review 1997 Sheffield, United Kingdom: National Health Services Breast Screening Programme, 1997.
  • 18 Blanks RG, Day NE, Moss SM. Monitoring the performance of breast screening programmes: use of indirect standardization in evaluating the invasive cancer detection rate. J Med Screen 1996; 3:79-81.

Article History

Published in print: May 2000