Table 1.
Classification of patients with T1 invasive melanoma according to the 2001 and 2009 AJCC staging and classification system (N = 106).
| Melanoma categories | 2001 AJCC, 6th edition | 2009 AJCC, 7th edition | Reclassified T1 melanomas according to 2009 AJCC staging | Median BT in mm (range) | ||||
|---|---|---|---|---|---|---|---|---|
| Clark level | Mitosis | Ulceration | T1a | T1b | T1a | T1b | ||
| II | − | − | 31 | 0 | 31 | 0 | No | 0.30† (0.12–1.0) |
| II | + | − | 3 | 0 | 0 | 3 | Yes | 0.70 (0.44–0.80) |
| II | − | + | 0 | 1 | 0 | 1 | No | 0.64 (0.64–0.64) |
| II | + | + | 0 | 0 | 0 | 0 | No | — |
| III | − | − | 14 | 0 | 14 | 0 | No | 0.55 (0.38–0.85) |
| III | + | − | 12 | 0 | 0 | 12 | Yes | 0.79 (0.35–1.0) |
| III | − | + | 0 | 0 | 0 | 0 | No | — |
| III | + | + | 0 | 3 | 0 | 3 | No | 0.90 (0.65–0.94) |
| IV | − | − | 0 | 16 | 16 | 0 | Yes | 0.55 (0.32–0.98) |
| IV* | + | − | 0 | 26 | 0 | 26 | No | 0.70 (0.44–0.98) |
| IV | − | + | 0 | 0 | 0 | 0 | No | — |
| IV | + | + | 0 | 0 | 0 | 0 | No | — |
|
| ||||||||
| Total | 60 | 46 | 61 | 45 | 31 | 0.60 (0.12–1.0) | ||
Reclassified T1a and T1b cohorts are listed in bold. Median BT of 0.30 mm was significantly lower compared to BT in other categories†: (P < 0.01). Mitosis “+”: 1 or more dermal tumor mitosis/mm2; mitosis “−”: <1 or 0 dermal tumor mitosis/mm2; ulceration “+”: histological absence of epidermis with accompanying inflammatory crust; ulceration “−”: histologically intact epidermis; BT: Breslow thickness; *category with positive sentinel lymph node biopsy (SLNB).