Would you offer consolidative RT to a patient with early stage, non-bulky, high-grade non-Hodgkin's lymphoma of the orbit after 6 cycles of RCHOP + IT chemotherapy?  

Yes I would. The high grade nature of disease and the location would be enough to convince me. There are now several large, single institution series that show that the pattern of failure is the same in patients with unfavorable DLBCL (non GCB type, DH/DL, Ki-67> 90, CD5+, Burkitt’s type DL...