Fig. 1
Dissemination of melanoma cells as function of tumour thickness. a Yellow function: estimated cumulative probability of dissemination as a function of tumour thickness (Turnbull) (n = 1027 patients). Blue line: Standard log-logistic distribution incorporating a fraction of patients without long-term dissemination (95% CI: blue dashed lines). Upper black dashed line: only 65.2% of melanomas disseminate lymphatically (95% CI: 60.4–70.0%). Fifty percent of this value (32.6%) provides the median thickness (0.5 mm, 95% CI: 0.3–0.7 mm) of disseminating melanomas (lower black dashed line). b Comparative analysis of histopathological and immuncytological SLN halves. Displayed are representative examples with immunocytological scores of DCCD ≤ 100, 100 < DCCD ≤ 1000 and DCCD > 1000. Samples LN 72 and LN 89 are stained against melan A LN 10, LN 135 and LN 168 against S100. LN 154 shows a highly pigmented melanoma in H&E staining. A close-up of the subcapsular region 3 is shown in the main figure; more central or core regions 1 and 2, see Supplementary Fig. 4a for higher magnification. c Evaluation of histopathological findings in corresponding sections of samples with a positive DCCD < 100. d Percentage of DCC-positive patients (n = 525) with colonisation (DCCD > 100) according to the Turnbull estimate (yellow). The percentage of colonisation (blue curve, 95% CI blue dashed curves) is described by a cumulative exponential distribution function (median 10.3 mm; 95% CI: 8.4–13.0 mm). e Hazard functions for dissemination (yellow line), and colonisation (blue line) describing the instantaneous risk per unit thickness for an event (dissemination, n = 1027; colonisation, n = 525) for those tumours, for which it has not yet occurred (de novo dissemination/ colonisation). f Survival analysis of melanoma patients (n = 1027) according to T stage (T1: ≤ 1 mm (n = 83); T2: 1.01–2.0 mm (n = 496); T3: 2.01–4.0 mm (n = 315); T4: >4 mm thickness (n = 133); log-rank test, p < 0.001)
