The odds of staying in are pretty good if you work hard and don't succumb to the stress. Many surgeons do not like to retire. In fact, it is an urban legend that surgeons die within a year after retirement because they don't know what to do with themselves. A brain surgeon in their 70s is not uncommon. At least you know they've got a lot of experience. By staying sane and fit, you too can make it a lifelong career.