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. Author manuscript; available in PMC: 2011 Aug 25.
Published in final edited form as: Stat Med. 2010 Nov 30;30(7):709–717. doi: 10.1002/sim.4131

Table III.

(a) Pertinent summary statistics on the survival endpoints of interest. Disease-free survival (DFS) is defined as time until a clinically detectable recurrence at any site (no melanoma deaths occurred without recurrence). Distant-disease-free survival (DDFS) is specific to recurrence at a distant site and includes death from melanoma without a distant recurrence. The two subgroups are patients with sentinel-node metastases (node +) and those absent metastases (node −). (b) Results from the two-sample ITT analysis estimating the effectiveness of the new standard of care; the parameter estimates are from Weibull accelerated failure time models. (c) Results from a model to estimate efficacy of lymphadenectomy on node-positive patients without covariates. (d) Follow-up analysis of DDFS to investigate covariate effects.

Treatment, node + (N = 122) Treatment, node − (N = 642) Control (N = 500)
(a) Summary statistics on survival endpoints (N = 1264)
Recurrence at any site—per cent 44.3 16.0 26.8
Distant recurrence—per cent 36.9 12.3 17.8
DFS (months)—median 37.9 59.1 54.5
DDFS (months)—median 43.8 59.8 59.9
(b) Two-sample intention-to-treat test of effectiveness (N = 1264)
Effectiveness 95 per cent interval p-Value
DFS 0.344 (0.0782, 0.609) 0.0112
DDFS 0.0708 (−0.201, 0.343) 0.610
(c) Two-sample test of efficacy in node-positive subgroup (N = 1264)
Efficacy (ψ̂1) 95 per cent interval p-Value
DFS 1.593 (1.167, 2.019) 2.4E–13
DDFS 0.937 (0.119, 1.755) 0.0247
(d) Regression analysis of DDFS with covariates (N = 1147)
Shared parameters Estimate 95 per cent interval p-Value
 Breslow thickness −0.528 (−0.739, −0.318) 8.6E–7
 Trunk (site) −0.486 (−0.766, −0.205) 6.8E–4
Node +
 Treatment efficacy 1.135 (0.402, 1.869) 0.0024
 Ulceration 0.179 (−0.377, 0.735) 0.527
Node −
 Ulceration −0.639 (−1.007, −0.270) 6.8E–4