, diminishing the value and accuracy of an independent analysis.
In a novel effort to determine whether previous interpretations sway second opinions, 149 dermatopathologists were asked to read melanocytic skin biopsy specimens without access to the initial pathology report. A year or more later they read them again but now with access to the initial reading.
Dr. Joann G. Elmore
The study showed that the participants, independent of many variables, such as years of experience or frequency with which they offered second options, were more likely to upgrade or downgrade the severity of the specimens in accordance with the initial report even if their original reading was correct.
If the goal of a second dermatopathologist opinion is to obtain an independent diagnostic opinion, the message from this study is that they “should be blinded to first opinions,” according to the authors of this study, led by Joann G. Elmore, MD, professor of medicine, University of California, Los Angeles. The study was published online in JAMA Dermatology.
Two-phase study has 1-year washout
The study was conducted in two phases. In phase 1, a nationally representative sample of volunteer dermatopathologists performed 878 interpretations. In phase 2, conducted after a washout period of 12 months or more, the dermatopathologists read a random subset of the same cases evaluated in phase 1, but this time, unlike the first, they were first exposed to prior pathology reports.
Ultimately, “the dermatologists provided more than 5,000 interpretations of study cases, which was a big contribution of time,” Dr. Elmore said in an interview. Grateful for their critical contribution, she speculated that they were driven by the importance of the question being asked.
When categorized by the Melanocytic Pathology Assessment Tool (MPAT), which rates specimens from benign (class 1) to pT1b invasive melanoma (class 4), the influence of the prior report went in both directions, so that the likelihood of upgrading or downgrading went in accordance with the grading in the original dermatopathology report.
As a result, the risk of a less severe interpretation on the second relative to the first reading was 38% greater if the initial dermatopathology report had a lower grade (relative risk, 1.38; 95% confidence interval [CI], 1.19-1.59). The risk of upgrading the second report if the initial pathology report had a higher grade was increased by more than 50% (RR, 1.52; 95% CI, 1.34-1.73).
The greater likelihood of upgrading than downgrading is “understandable,” Dr. Elmore said. “I think this is consistent with the concern about missing something,” she explained.
According to Dr. Elmore, one of the greatest concerns regarding the bias imposed by the original pathology report is that the switch of opinions often went from one that was accurate to one that was inaccurate.
If the phase 1 diagnosis was accurate but upgraded in the phase 2 diagnosis, the risk of inaccuracy was almost doubled (RR, 1.96; 95% CI, 1.31-2.93). If the phase 1 report was inaccurate, the relative risk of changing the phase 2 diagnosis was still high but lower than if it was accurate (RR, 1.46; 95% CI, 1.27-1.68).
“That is, even when the phase 1 diagnoses agreed with the consensus reference diagnosis, they were swayed away from the correct diagnosis in phase 2 [when the initial pathology report characterized the specimen as higher grade],” Dr. Elmore reported.
Conversely, the risk of downgrading was about the same whether the phase 1 evaluation was accurate (RR, 1.37; 95% CI, 1.14-1.64) or inaccurate (RR 1.32; 95% CI, 1.07-1.64).
Downward and upward shifts in severity from an accurate diagnosis are concerning because of the likelihood they will lead to overtreatment or undertreatment. The problem, according to data from this study, is that dermatologists making a second opinion cannot judge their own susceptibility to being swayed by the original report.