What is the clinical benefit of preoperative chemoradiotherapy with 5FU/leucovorin for T3-4 rectal cancer in a pooled analysis of EORTC 22921 and FFCD 9203 trials: Surrogacy in question?

Preoperative CRT does not prolong OS or PFS. pCR or LC do not qualify as surrogate for PFS or OS while PFS is surrogate. Phase III trials should use OS or PFS as primary endpoint.