consider that from my personal search and email one or two years ago, to the main contributors and directors of the TCGA project-which "evolved" to GDC, i got the following answer : "The criterion used for all of the TCGA projects, is that samples be obtained from the primary tumor site from patients who have not received any prior treatment"-
moreover, consider the fact that it would not make any impact, if for the initial characterization of primary cancers of different origins, specimens used from patients that had any type of therapy-
however, i don't know about extra information, adjuvant therapy that applied after initial treatment (that is surgery), etc.
I think all is included in the clinical tab information in GDC, which is available for every project.
Also, you should have also checked firstly the relative publication:
https://www.nature.com/articles/nature13385#s1 - it has a section as every similar TCGA paper, describing the patient cohorts and characteristics.