Table 3.
Interobserver concordance of histological grading for invasive breast carcinoma among different pathologists interpreting the same cases (interobserver concordance) by study phase and interpretive format (22 invasive cases)
| Interobserver concordancea | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Phase of study and format | Number of pathologists | Number of paired interpretations | κb (95% CIs) | Agreementc (95% CIs) | ||||||
| T | N | M | Nottingham grade | T | N | M | Nottingham grade | |||
| Phase I | ||||||||||
| Glass slide format | 115 | 17,162 | 0.51 (0.50-0.52) | 0.22 (0.21-0.24) | 0.42 (0.40-0.43) | 0.48 (0.47-0.49) | 71 (69-73) | 58 (56-59) | 74 (72-77) | 68 (66-70) |
| Digital format | 93 | 10,562 | 0.40 (0.39-0.42) | 0.22 (0.20-0.23) | 0.25 (0.23-0.27) | 0.32 (0.31-0.34) | 67 (65-70) | 58 (56-61) | 70 (67-73) | 60 (57-62) |
| Phase II | ||||||||||
| Glass slide format | 86 | 9362 | 0.47 (0.45-0.48) | 0.25 (0.23-0.27) | 0.45 (0.44-0.47) | 0.49 (0.48-0.51) | 71 (68-73) | 56 (54-59) | 76 (73-78) | 69 (67-71) |
| Digital format | 86 | 9472 | 0.37 (0.35-0.38) | 0.17 (0.15-0.19) | 0.23 (0.21-0.25) | 0.36 (0.34-0.37) | 65 (62-67) | 56 (53-58) | 68 (65-70) | 62 (60-64) |
aAll pairwise combinations excluding overlapping pathologists, bSimple κ coefficient, cGEE multivariable modeling. CIs: Confidence intervals, T: Tubular score, N: Nuclear pleomorphism grade, M: Mitotic score, GEE: General estimating equation