Diagnostic Reproducibility: What Happens When the Same Pathologist Interprets the Same Breast Biopsy Specimen at Two Points in Time?
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Surgeons may receive a different diagnosis when a breast biopsy is interpreted by a second pathologist. The extent to which diagnostic agreement by the same pathologist varies at two time points is unknown.
Pathologists from eight U.S. states independently interpreted 60 breast specimens, one glass slide per case, on two occasions separated by ≥9 months. Reproducibility was assessed by comparing interpretations between the two time points; associations between reproducibility (intraobserver agreement rates); and characteristics of pathologists and cases were determined and also compared with interobserver agreement of baseline interpretations.
Sixty-five percent of invited, responding pathologists were eligible and consented; 49 interpreted glass slides in both study phases, resulting in 2940 interpretations. Intraobserver agreement rates between the two phases were 92% [95% confidence interval (CI) 88–95] for invasive breast cancer, 84% (95% CI 81–87) for ductal carcinoma-in-situ, 53% (95% CI 47–59) for atypia, and 84% (95% CI 81–86) for benign without atypia. When comparing all study participants’ case interpretations at baseline, interobserver agreement rates were 89% (95% CI 84–92) for invasive cancer, 79% (95% CI 76–81) for ductal carcinoma-in-situ, 43% (95% CI 41–45) for atypia, and 77% (95% CI 74–79) for benign without atypia.
Interpretive agreement between two time points by the same individual pathologist was low for atypia and was similar to observed rates of agreement for atypia between different pathologists. Physicians and patients should be aware of the diagnostic challenges associated with a breast biopsy diagnosis of atypia when considering treatment and surveillance decisions.
KeywordsBreast Density Atypical Ductal Hyperplasia Agreement Rate Intraobserver Agreement Breast Pathology
The authors appreciate the efforts of the pathologists who participated in this study. Supported in part by the National Cancer Institute of the National Institutes of Health (R01 CA140560, U54 CA163303, KO5 CA104699, and R01 CA172343); and by the National Cancer Institute–funded Breast Cancer Surveillance Consortium (HHSN261201100031C). The content is solely the responsibility of the authors and does not necessarily represent the views of the National Cancer Institute or the National Institutes of Health. The collection of cancer and vital status data used in this study was supported in part by several state public health departments and cancer registries throughout the United States. A full description of these sources is available online (http://www.breastscreening.cancer.gov/work/acknowledgement.html).
The authors declare no conflict of interest.
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