If the OP is seriously in rad onc, the "do what you want, where you want, for the salary you want" (choose 2 of the above only) is 100% true for his specialty (as it is for the majority of other specialties). Hell, given the market for Rad Onc, he can probably choose all 3 of the above.
I am a rad onc resident. This is untrue. Some of the other information in this thread paints an unrealistic picture of radiation oncology.
The rad onc job market is tight this year. This is a small specialty that is taking some reimbursement cuts (
https://www.astro.org/Advocacy/Medicare-Cuts.aspx). Private practices and hospitals are nervous about hiring these days, since they are worried about these and future cuts to the specialty. Because the field is so small, a drop in hiring dramatically influences the job market for new graduates. Since it's bad this year, a lot of doom and gloom has spread among some residents. It's no better in academics, where grants are very tight. Less scrupulous groups and hospital systems are happy to hire graduates with limited job opportunities and exploit their revenue earning potential while paying them little.
This isn't just theoretical. Competitive job markets have been terrible in rad onc for years. Obtaining a permanent position in major northeastern cities, California, and some other areas are practically impossible for new graduates without serious connections. Even for well established attendings, these job markets can be extremely difficult. There are many senior attendings in SoCal kicking around practice after practice still trying to find something decent. Sure, you may find a job in the competitive location you want, but the salary and practice specifics may be particularly bad. In some areas, you may not even find any position within a 50+ mile radius.
Regardless of the reality check, I love rad onc and wouldn't trade this specialty for anything else. That said, there are some fairly malignant programs in the specialty that work their residents very hard. There are some programs that are not educationally driven, using residents as servants for lazy attendings who teach little. But, there are many graduates of those programs who read, work hard, and go on to achieve their goals.
The reality is that no matter what happens to the specialty, you will almost certainly have a high paying job in the end. Whatever you do find, it will likely pay well over the average physician pay of 200k/year. The average pay in consulting is nowhere near that. Do not give up the stable career you have worked so hard for! A lot of people at my own institution seem to have a "grass is greener on the other side" mentality for other medical specialties and careers. They focus on the positives and the big success stories, and forget that other specialties have downsides. They forget that positions in other industries are nowhere near as secure as medicine.
You have invested so much to become a radiation oncologist, and you have only a relatively short period of time to go. You don't even need a fellowship in this specialty to find a great position! To throw all of that hard work away now seems incredibly shortsighted to me. Finish residency, look at the job market, get board certified, and then consider whether you want to continue being a radiation oncologist or want to dabble in the business or some other world. Because the grass looks greener now, but I suspect it truly is not.