Heal testicular tumor without surgery?

Hello,

I was diagnosed with a testicle tumor of 5mm size in my testicle this morning through sonography. I somehow can't believe it, as I thoroughly searched it for any abnormalities when I had an unfortunate hit to the groin about two weeks ago.
I could swear, there was nothing of a lump back then. Now yesterday I found this really small, but slighty hard lump. The doc today recommended to go to a hospital and have surgery. He seemed to believe in a tumor. Problem is, since I'm in Japan right know, there is probably a lot I'm missing through language barrier (or not being told to not make things complicated) and he didn't even find it at first and wanted to send me home. Now he wants a surgery after just a sonography.
Now I can't believe a cancer has developed within like two weeks and want to rule out, that cutting out a testicle is necessary and its just a scar or something from the groin hit before.

I'm thinking about postponing the surgery date as much as safely advisable and Water Fast till then, which might be about a week at most I guess. Maybe I can see a reduction in size till then, telling me if I'm on the right track? It is just 5mm and it feels strange to loose a testicle to something thats smaller than an average pea.

I find tons of people who fasted instead of going for chemo therapy, but are there actually any people who used it as an alternative for the surgery?
What would be the danger of waiting and fasting, could I worst case at least expect the fast to halt the growth for the time being in as not making worse till a postponed surgery?
Many thanks in advance!
Mike