The best arm of the RICOVER-60 trial ( 6R-CHOP-14 +2 R [ R-CHOP administered once every 2 weeks plus two additional applications of rituximab ] plus involved-field RT [ 36 Gy ] to sites of initial bulky [ 7.5 cm ] disease and extralymphatic involvement ) was compared with a cohort receiving the same immunochemotherapy but without RT in an amendment to the RICOVER-60 trial ( RICOVER-noRTh ) in a prospective fashion .