Hello Phil, my cancer was different but I would like to offer my best wishes for a positive outcome. I would say definitely make a sperm bank donation so you can be assured of your ability to look forward to building your family after you recover from this traumatic event for both of you. You can still ask if it’s ok when going thru treatment. Even after treatment I think it’s a good idea to keep a reserve bank. I am being monitored and tested for the same possibility of cancer. I don’t have the worry you have about starting a family as I’m 77 and have a daughter. Please keep your strength up and be positive about the treatment in front of you  take care Phill and if you can… send me an update now and then.  Good wishes from Ron and Pauline.