That can be dangerous. One of my uncles had a mole removed from the back of his arm, that was diagnosed as pre-cancerous. The doctors told him chemo probably wasn't necessary, but offered it as an option. He told them, if they thought it wasn't necessary, he wouldn't have it. 6 months later he had cancer in pretty much every major organ in his body, and he died not long after.
Prostate cancer can be detected so early now that the doctors probably think chemo isn't necessary. I'm hoping for Sir Ian's sake they're right.
I hope that's right. I had two family members diagnosed with cancer. Both did chemo and radiation and one did surgery. All it did for them was make their last months miserable.