Table 2.

Clinical characteristics by metastasis status and class prediction for the development, training, and validation cohorts of patients with cutaneous melanoma

Training set (n = 164)Validation set (n = 104)
NonmetastasisMetastasisClass 1Class 2NonmetastasisMetastasisClass 1Class 2
(n = 97)(n = 67)(n = 88)(n = 76)Pa(n = 69)(n = 35)(n = 61)(n = 43)P
Follow-up time (y), median (range)6.8 (0.06–13.7)7.3 (2.3–13.7)6.6 (0.1–11.5)7.3 (0.5–11.9)7.3 (0.8–11.9)7.4 (0.5–10.5)
Time to metastasis (y), median (range)1.5 (0–7.8)2.7 (0.6–7.8)1.3 (0–7.6)1.4 (0–9.17)4.1 (0–9.2)1.4 (0–5.8)
Age (y), median (range)57 (23–87)68 (23–89)58 (31–86)64 (23–89)0.0455 (18–86)63 (28–94)54 (18–82)66 (28–92)0.002
AJCC stage<0.001<0.001
 01501500000
 I549576560506
  IA325352380371
  IB213204150105
 II2839165113211024
  IIA161510217658
  IIB817520611512
  IIC370100404
 III018018012111
 IV01010202
Breslow thickness (mm)<0.001<0.001
 Median (range)1.0 (0.3–10.4)2.8 (0.15–16)0.8 (0–5.2)2.9 (0.15–16)0.8 (0.13–7)3.99 (0.9–10)0.7 (0.1–7)3.4 (0.9–10)
 <1 mm386572431431
 1–1.99 mm1911181211478
 2–3.99 mm182810361112716
 >4 mm720126417417
Ulceration<0.001<0.001
 Absent782673315694817
 Present1135640523424
Mitotic rate0.320.06
 <1/mm218161815133134
 ≥1/mm25245425438263233
Location0.180.25
 Head and neck2426212815101312
 Trunk22111915238229
 Extremity5130483331172622

NOTE: P values reflect differences in class prediction and were determined by χ2 or Fisher exact tests.