i think you are right for most of these. i believe rad onc is a year of transition + 4 years rad onc. i think most people who do onc generally always do heme also because of leukemia etc. i think people may do oncology by itself and thus choose not to deal with blood disorders, but i think the opposite is untrue. it would be very difficult to sustain a practice with just hematology (it makes up 20-30% of an heme-oncologists practice).
in terms of deciding between rad onc and heme/onc...
on one hand rad-onc definately seems to have a good lifestyle in residency and afterward. but you can get that in heme/onc too depending on the practice you choose. you may not make as much money in heme-onc. residency in heme/onc does require 3 years on internal med which may not be appealing for everyone. rad onc is quite different, in that you focus on radiation therapy, its dosing, its location and is usually more procedural. Heme onc relies on the chemotherapeudics and often requires referrals to the radiation oncologist. some say that you get to know patients better in heme onc since you are often their primary cancer doctor and thus its more personal.
good luck deciding. either way, they are great fields with great potential.
