Reviewer response for version 1
This paper is generally well-written, with a clear and concise description of the problem and challenge. 
The author adopted a two-step feature selection procedure: a penalized L 1 regression for Cox PH model (R package "glmpath") in the first step, and forward selection in the second step. 
Features are selected to optimize the iAUC (integrated time-dependent AUC) in 10-fold cross validation.
Major comments:
I am confused about how the two-step feature selection procedure works. 
The author mentioned the following
- " Among selected features described above, my procedure further implemented a forward feature selection to narrow the list of clinical variables ."
- " This figure shows that the step maximizing AUC is the sixth step which includes six clinical variables ALP, AST, ECOG_C, HB, MI and PLT. 
These clinical variables were finally selected to predict global risks and survival times of patients ."
" 
Therefore, I assume the second step starts with the features selected from the first step. 
However, the features shown in Table 2 don't appear to be a subset of the features shown in Table 1. 
Also, the feature "MI" doesn't appear to be in Table 1.
Minor comments:
- The difference between sub-challenge 1a and sub-challenge 1b is not documented in the Introduction. 
Please explain that in sub-challenge 1a, the submissions consist of the risk scores, while in sub-challenge 1b, the submissions consist of the predicted survival time.
- Under Results and "Selected clinical variables", the author mentioned that " My method removed clinical variables having a lot of missing values and then it used only 14 numerical clinical variables and 56 categorical clinical variables with less number of missing values .". 
What are the exact criteria for filtering clinical variables given that there are 150+ clinical variables to start with?
- Please explain what the clinical variables mean (e.g. ENTRTPC, ALP, HB, AST, ECOGC, NEU, PLT, PSA and LDH in Table 1).
- Please expand the captions for Table 1 and Table 2 to put these tables in the context of the 2-step feature selection procedure.
- In Table 3, I assume the circle means "yes" and the cross means "no". 
Please add a legend to the caption.
Structure
Strength
Recap
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Structure
Weakness
Other
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Other
Other
Weakness
Weakness
Structure
Weakness
Todo
Recap
Todo
Todo
Todo
Other
Todo