Stopping treatment - or are there some options?

Hi All.

I've been having treatment for stage 4 bowel cancer over the last two years (one 17mm met in liver & four ~12mm mets in lungs). I've had a range of chemo drugs and targeted drugs. For a while the drugs seemed to at least be holding things in balance, but at my last scan back in January the tumours had all grown. My Dr suggested that it may be the time to consider stopping treatment to at least have a degree of quality of life for however long was left. They felt the treatments were no longer working. I opted for another course of Folfox (the very first treatment I had two years ago, as this was the most successful of all the drugs I had). My thinking was just maybe this would knock it back a bit and at least inform on whether there was another course to keep me going for longer. A long-shot. 

Throughout my treatment the side effects have been miserable (lots of nausea, sickness etc), regardless of the different anti-sickness I've tried - so I know that continuing with drugs like Folfox or Folfiri longer term is not a viable option. 

I guess I'm seeking any advice that I could then discuss with my Dr from anyone whose tried and succeeded with other drugs/techniques please? I know my cancer can't be cured, but if there were things out there that can extend, whilst allowing some quality of life. 

I've had Folfox, Folfiri (with Cetuximub), Lonsurf (with Bevicizimub) so far. Approx 30 cycles in total. The Dr mentioned there was a 4th line that could be considered but felt that it was highly unlikely to work and would just cause more side-effects for no gain.

Many thanks for any help

Thanks

Dave