Survival analysis for PAN-TCGA dataset

Question

[rt.cgen]

I am trying to run survival analysis (KM plot) for a set of genes on PAN-TCGA dataset, I am aware of tools like RTCGAToolBox that can help in downloading and running these analysis for a cancer type at a time. I have also tried cbioportals' web-API and R package ("cgdsR"). I finally resorted to using R package "survival" but that isn't helpful either. There are easy ways to run survival analysis for one cancer type but so far I haven't found anything that computes survival analysis for many cancer type for a set of genes.

TL;DR - Survival analysis for cumulative TCGA dataset (spanning a few TCGA dataset) for a set of genes.

Any help would be greatly appreciated. TIA