I could feel a mass in my right lower abdomen. That's what took me to the doc. I thought (hoped) it was a hernia. It wasn't. 18months earlier I explored persistent pain in the same area, had a ct scan then that showed nothing too remarkable. Now I wish I'd been more agressive in pursuing a cause for the pain. i perhaps could have been diagnosed at stage 1 rather than 3. Oh well, as the nurse told me, "You can't go back there now." But I can hope that others learn from my experience. Be agressive about your own care. Be a nuisance even!
My Oncologist as well could feel tumors when I was being examined.
I can feel some of mine - however they were identified on a scan first. My Oncologist often gets med students to comment on them (he often has a student with him at appointments) - they invariably suggest they are scar tissue before suggesting they are tumours.