Do Physicians Remember Cases? Implications for Longitudinal Designs in Medical Research and Competency Assessment

In pathology and other specialties of diagnostic medicine, longitudinal studies and competency assessments often involve physicians interpreting the same images multiple times. In these designs, a washout period is used to reduce the chances that later interpretations are influenced by prior exposure.

The present study examines whether a washout period between 9-39 months is sufficient to prevent three effects of prior exposure when pathologists review digital breast tissue biopsies and render diagnostic decisions: faster case review durations, higher confidence, and lower perceived difficulty.

In a longitudinal breast pathology study, 48 resident pathologists reviewed a mix of five novel and five repeated digital whole slide images during Phase 2, occurring 9-39 months after an initial Phase 1 review. Importantly, cases that were repeated for some participants in Phase 2 were novel for other participants in Phase 2. We statistically tested for differences in participants' case review duration, self-reported confidence, and self-reported difficulty in Phase 2 based on whether the case was novel or repeated.

No statistically significant difference in review time, confidence, or difficulty as a function of whether the case was repeated or novel in a Phase 2 review occurring 9-39 months after initial viewing; this same result was found in a subset of participants with a shorter (9-14-month) washout.

These results provide evidence to support the efficacy of at least a 9-month washout period in the design of longitudinal medical imaging and informatics studies to ensure no detectable effect of initial exposure on participant's subsequent case review.