The only way to know is to talk to a broker and find out. Since it was benign you can probably just call a few insurance companies and ask for quotes.
I'm not sure how that specific tumor will affect your rates, but here's my story. I had metastatic testicular cancer in 2012. Now, after chemo and surgery I've been in remission for two years. I pay $340/mo for a $250k 20 year term policy.
Edit to add: that $340/mo includes an additional premium for the first five years of the policy, then it drops to standard rate (like $300/year total). It's definitely not $340/mo for all 20 years.