EVALUATION OF INTEROBSERVER DISCREPANCY IN HISTOLOGIC GRADING OF BREAST CARCINOMA, PAPILLARY BLADDER CARCINOMA, AND SOFT TISSUE SARCOMA

Histologic tumor grading is a well-documented useful, inexpensive and easily
done prognostic factor but it shows many differences when viewed by multiple pathologists. The aim of
the present study was to determine the interobserver differences in tumor grading among pathologists
in Urmia, Imam Khomeini Hospital.
Materials & Methods: In this descriptive, analytical retrospective study, 50 cases of breast carcinoma,
urothelial papillary tumor and soft tissue sarcoma were evaluated. Three pathologists reviewed all slides
and graded the tumors after codifying and without any knowledge of the opinion of each other. The
interobserver concordance was determined by K statistics. A p< 0.05 is considered significant.
Results: The interobserver concordance was fair in grading of breast, and bladder carcinoma and
moderate in soft tissue sarcoma (Kappa was 0.3, 0.13 and 0.603, respectively). Based on the evaluation
of factors included in histologic grading, the agreement was higher for pleomorphism in breast cancer,
cellular thickness layer in bladder tumor, and cellular differentiation in soft tissue sarcoma (Kappa was
0.8, 0.28 and 0.65, respectively).
Conclusion: According to our results, interobserver concordance in the grading of different tumors was
fair. To solve this problem, it is suggested to do grading more than one time and in different microscopic
fields. Simultaneous grading by two pathologists with multi-head microscope or considering the average
of what two pathologists achieve separately can be useful.