PFS for Control Schedule and Schedule X for 5 Alliance trials enrolling patients with untreated FL from 2008-2016. Kaplan-Meier curves for C50701 (phase 2, epratuzumab/rituximab), C50803 (phase 2, lenalidomide/rituximab), C50904 (phase 2, ofatumumab/bendamustine vs ofatumumab/bendamustine/bortezomib), C50901 (phase 2, ofatumumab), and A051103 (phase 1, rituximab/lenalidomide/ibrutinib) demonstrate minimal difference in 2- and 4-year PFS when scans are performed according to protocol (Control Schedule) vs omitting every other scan (Schedule X).