>You don't have to worry about some other doctors accessing your information in bulk to try and conduct a study on cancer rates.

This not only happens, it's my job (though I'm not a doctor). Of course, it's tightly controlled on my end. I work for the government, but health systems have their own analysts. As part of my job, I have access to sensitive and identifying information.

This isn't to be contrairian. There are existing systems using very personal data in bulk for analysis. The wheel doesn't need reinvented.