Table 1.
Clinicopathological characteristics of the model development and validation cohorts
| EORTC (n = 3180) | MIA (n = 4235) | P † | |
|---|---|---|---|
| Age at diagnosis (years) * | 55 (44–67) | 58 (47·5–68·5) | |
| Sex | < 0·001 | ||
| M | 1668 (52·5) | 2463 (58·2) | |
| F | 1510 (47·5) | 1772 (41·8) | |
| Missing | 2 (0·1) | 0 (0) | |
| Primary tumour site | < 0·001 | ||
| Head and neck | 259 (8·1) | 716 (16·9) | |
| Upper limb | 556 (17·5) | 844 (19·9) | |
| Lower limb | 996 (31·3) | 1060 (25·0) | |
| Trunk | 1360 (42·8) | 1615 (38·1) | |
| Missing | 9 (0·3) | 0 (0) | |
| Breslow thickness * | 1·7 (1·1–3·0) | 1·8 (1·0–2·6) | |
| Tumour mitotic rate (per mm 2 ) * | n.a. | 3·0 (0·5–5·5) | |
| 0 | 39 (1·2) | 417 (9·8) | < 0·001 |
| ≥ 1 | 112 (3·5) | 3631 (85·7) | |
| Missing | 3029 (95·3) | 187 (4·4) | |
| Ulceration | 0·944 | ||
| No | 2264 (71·2) | 2890 (68·2) | |
| Yes | 788 (24·8) | 1002 (23·7) | |
| Missing | 128 (4·0) | 343 (8·1) | |
| Melanoma subtype | < 0·001 | ||
| Superficial spreading melanoma | 1739 (54·7) | 1731 (40·9) | |
| Nodular melanoma | 885 (27·8) | 1295 (30·6) | |
| Acral lentiginous melanoma | 93 (2·9) | 62 (1·5) | |
| Lentigo maligna melanoma | 139 (4·4) | 85 (2·0) | |
| Other | 46 (1·4) | 442 (10·4) | |
| Missing | 278 (8·7) | 620 (14·6) | |
| Clark level | < 0·001 | ||
| I–II | 271 (8·5) | 58 (1·4) | |
| III | 1230 (38·7) | 1147 (27·1) | |
| IV | 1354 (42·6) | 2615 (61·7) | |
| V | 140 (4·4) | 326 (7·7) | |
| Missing | 185 (5·8) | 89 (2·1) | |
| Regression | |||
| None | n.a. | 1228 (29·0) | |
| Early/intermediate | n.a. | 2011 (47·5) | |
| Late | n.a. | 348 (8·2) | |
| Missing | n.a. | 648 (15·3) | |
| Vascular invasion | |||
| No | n.a. | 3371 (79·6) | |
| Yes | n.a. | 81 (1·9) | |
| Missing | n.a. | 783 (18·5) | |
| Lymphovascular invasion | |||
| No | n.a. | 2876 (67·9) | |
| Yes | n.a. | 77 (1·8) | |
| Missing | n.a. | 1282 (30·3) | |
| Total no. of SNs * | 1 (1–2) | 2 (1–3) | |
| Drainage site of identified SNs | |||
| Axilla | n.a. | 2215 (52·3) | |
| Groin | n.a. | 1174 (27·7) | |
| Neck | n.a. | 794 (18·7) | |
| Other | n.a. | 52 (1·2) | |
| No. of drainage sites | |||
| 1 | n.a. | 3436 (81·1) | |
| 2 | n.a. | 717 (16·9) | |
| 3 | n.a. | 73 (1·7) | |
| 4 | n.a. | 9 (0·2) | |
| No. of SN fields | < 0·001 | ||
| 1 | 2768 (87·0) | 3436 (81·1) | |
| > 1 | 412 (13·0) | 799 (18·9) |
Values in parentheses are percentages unless indicated otherwise;
*
values are median (i.q.r). EORTC, European Organisation for Research and Treatment of Cancer; MIA, Melanoma Institute Australia; n.a., not available; SN, sentinel node.
†
Pearson's χ2 test.