as Say again s l o w l y and North County Pilot both know, I had NHL diagnosed last July after a laparotomy to remove a tumour. Has 6 months of chemo and have just got my Class One medical back, no OML or other restrictions - I'm back doing single pilot emergency services helicopter work.
The bone marrow biopsy was hell, but don't worry, your ache in your bum will ease after a while....
In terms of timescale, the CAA needed 6 months wait from the final dose of chemo and then a full cardio review...24hr ECG, echocardiogram, treadmill ECG etc
It was the effects of the chemo drugs, not the disease, that worry them on the medical front.
If your doc says you're getting Rituximab and CHOP then that's what I had. I can email you the CAA flowchart for anthracycline treatment if you want to see the process of getting your medical back. Straightforward, just took a while. The gap in my logbook is from 22 Jun 06 to 29 Aug 07, so 14 months or so...but my chemo was largely precautionary as they took the tumour out (plus a huge margin inc bits of guts, spleen etc) and only lasted 6 cycles.
PM for a chat, more details etc Good luck!