Survival analysis

Hello there,

A package called maxstat can be used to select the "optimal cutoff" in survival analysis based on a biomarker (such as gene expression in TCGA): r-addict.com/2016/11/21/Optimal-Cutpoint-maxstat.html. Is this kind of over fitting? Say, given a random gene, choosing an optimal cutoff will increase the likelihood of getting significant result, which increases type 1 error.

This "optimal cutoff" method seems to be useful in classification or prediction task, but not for general test of the clinical significance of a gene.