Table 2.
Comparison of three-panel member’s independent reviews and final consensus interpretations according to MPATH-Dx diagnostic class (n = 201)
| Interpretations from independent reviews | Interpretations from consensus reviews
|
||||
|---|---|---|---|---|---|
| Nevus/mild atypia, n = 22 N (%) |
Moderate atypia, n = 33 N (%) |
Severe atypia/melanoma in situ, n = 55 N (%) |
T1a melanoma, n = 42 N (%) |
T1b melanoma, n = 49 N (%) |
|
| Nevus/mild atypia | |||||
| 0 of 3 pathologists agreed | 0 | 15 (45) | 53 (96) | 42 (100) | 49 (100) |
| 1 of 3 pathologists agreed | 1 (5) | 15 (45) | 2 (4) | 0 | 0 |
| 2 of 3 pathologists agreed | 8 (36) | 3 (9) | 0 | 0 | 0 |
| All 3 pathologists agreed | 13 (59) | 0 | 0 | 0 | 0 |
| Moderate atypia | |||||
| 0 of 3 pathologists agreed | 16 (73) | 2 (6) | 35 (64) | 41 (98) | 49 (100) |
| 1 of 3 pathologists agreed | 5 (23) | 10 (30) | 15 (27) | 1 (2) | 0 |
| 2 of 3 pathologists agreed | 1 (5) | 16 (48) | 5 (9) | 0 | 0 |
| All 3 pathologists agreed | 0 | 5 (15) | 0 | 0 | 0 |
| Severe atypia/melanoma in situ | |||||
| 0 of 3 pathologists agreed | 19 (86) | 16 (48) | 1 (2) | 24 (57) | 48 (98) |
| 1 of 3 pathologists agreed | 3 (14) | 13 (39) | 8 (15) | 13 (31) | 1 (2) |
| 2 of 3 pathologists agreed | 0 | 4 (12) | 21 (38) | 5 (12) | 0 (0) |
| All 3 pathologists agreed | 0 | 0 | 25 (45) | 0 | 0 (0) |
| T1a melanoma | |||||
| 0 of 3 pathologists agreed | 22 (100) | 33 (100) | 42 (76) | 0 | 44 (90) |
| 1 of 3 pathologists agreed | 0 | 0 | 13 (24) | 5 (12) | 5 (10) |
| 2 of 3 pathologists agreed | 0 | 0 | 0 | 17 (40) | 0 |
| All 3 pathologists agreed | 0 | 0 | 0 | 20 (48) | 0 |
| T1b melanoma | |||||
| 0 of 3 pathologists agreed | 22 (100) | 33 (100) | 55 (100) | 39 (93) | 0 |
| 1 of 3 pathologists agreed | 0 | 0 | 0 | 3 (7) | 0 |
| 2 of 3 pathologists agreed | 0 | 0 | 0 | 0 | 6 (12) |
| All 3 pathologists agreed | 0 | 0 | 0 | 0 | 43 (88) |
MPATH-Dx, Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis.
Kappa coefficients: Pair 1 – 0.54 (absolute agreement – 63.7%); Pair 2 – 0.59 (absolute agreement – 67.2%); Pair 3 – 0.61 (absolute agreement – 70.2%); 3-way overall – 0.58 (95% CI: 0.52–0.64).
Table 2 shows the full extent of agreement and where disagreements lie among the reference diagnosis panel members, ranging from no agreement to complete agreement according to diagnostic classes. The diagonal cells shaded in grey indicate agreement within each diagnostic category and the unshaded cells indicate where levels of agreement occurred across categories rather than within categories. Thus, for 95% of the cases with a reference consensus diagnosis of nevus/mild atypia cases, two or all three panel members interpreted those cases as such during their initial independent reviews, and none of them interpreted those cases as T1a or T1b melanoma. The majority of pathologists on the panel (two of three or all three of three) were also in agreement with the consensus diagnosis for severe atypia/melanoma in situ cases (83%), T1a melanoma cases (88%), and T1b melanoma cases (100%). The lowest level of agreement was for moderate atypia, where for 63% of cases the majority of panel members agreed that the case was moderate atypia in their initial interpretations. Interpretations for this category tended to cross over into severe atypia/melanoma in situ.