Development and Validation of Nomograms to Predict Local, Regional, and Distant Recurrence in Patients With Thin (T1) Melanomas.PURPOSE
 Each nomogram performance was evaluated using calibration plots defining low-risk and high-risk groups as the lowest and top 5% of the nomogram risk score, respectively.  The nomograms' C-statistics were compared with those of a model including the current American Joint Committee on Cancer staging parameters (T-stage and sentinel node status).


 Using the nomogram, the C-statistic was increased by 9%-12% for the development cohort and by 11%-15% for the validation cohort, compared with a model including only T-stage and sentinel node status.


 The presented nomograms can accurately identify a subgroup at high risk. 
Nomogram
Multivariable Cox models were generated for local, regional, and distant recurrence-free survival (RFS). 
Cox models
Discrimination was assessed using Harrell's C-statistic for each outcome. 
Harrell's C-statistic
Each nomogram performance was evaluated using calibration plots defining low-risk and high-risk groups as the lowest and top 5% of the nomogram risk score, respectively.  Calibration plots showed a good match between predicted and observed rates. 
calibration plots
An online calculator is available at www.melanomarisk.org.au.
online calculator