Pathology Reports: Discrepancy Patterns of Second Opinions in a Referral Cancer Center

To evaluate the diagnostic mismatch (discrepancy) of pathology reports in consulted specimens referred for second opinion.

This cross-sectional study was conducted at a major cancer center, Omid Hospital. In this study, 350 primary pathology reports and 350 reviewed pathology reports were extracted from the archives of Omid Hospital from 2011 to 2020 and assessed in terms of the extent of discrepancy, by two pathologists and one oncologist. The required data for each sample were entered into a checklist and then statistically analyzed. Cases with the same diagnosis on both reports were assigned to the matched group and the rest were assigned to the minor or major mismatch (discrepancy) group. Minor mismatches included changes in diagnosis that did not lead to changes in treatment (may lead to changes in prognosis or provide additional information to the oncologist) and major mismatches included changes in diagnosis leading to changes in treatment or remedies.

Two hundred seven cases (59.1%) out of three hundred fifty cases had concordant results between the diagnosis of the first pathologist and the reviewing pathologist. In one hundred forty-three cases (40.9%) mismatch (discrepancy) was observed, including eighty- two cases (23.4%) with minor mismatches (discrepancy) and sixty-one cases (17.4%) with major mismatches (discrepancy). In the major mismatch group, fifteen cases (4.3%) changed from malignant to benign, eighteen cases (5.1%) changed from benign to malignant, two cases (0.6%) changed from one stage to another stage of Disease and twenty-six cases (7.4%) had changes in the type of malignancy. In this study, it was found that there was no significant relationship between anatomical areas of sampling and diagnostic mismatch (p = 0.254). The study also found that the rate of diagnostic mismatch in specimens obtained by resection or excisional biopsy was greater than that of small biopsies (eighty cases (22.8%) and sixty-two cases (17.7%, respectively)). There was no significant relationship in this regard (p = 0.077).

Compared to most similar studies, the present study reported the highest discrepancy between the diagnosis of the first pathologist and the reviewing pathologist (40.9%).