How much does it cost to become a pediatric oncologist?

2 yrs general pediatric, 2 yrs pedi neurology, 2-3 yrs pedi neuro-oncology fellowship. it estimates a total of 6-7 yrs to become a pedi-neuro-oncologist. There are about a total of 60 -70 (or less) pedi neuro-oncologists in the world.