Who Do Doctors Sue for Malpractice?

A recent study produced some curious findings:
Physicians may choose riskier treatment for themselves than they'd recommend for their patients, according to a study that highlights a need for candid discussions about patients' preferences.
 The article goes on to explore some possible explanations:
The study asked more than 700 primary-care doctors to choose between two treatment options for cancer and the flu — one with a higher risk of death, one with a higher risk of serious, lasting complications.

In each of the two scenarios, doctors who said they'd choose the deadlier option for themselves outnumbered those who said they'd choose it for their patients.

That's likely because doctors are taught to do no harm, and death would be the ultimate harm. But also, some doctors likely reacted emotionally, recoiling at the notion of enduring "these kind of icky [is this a medical term?] side effects," and they tended to put more faith in patients' ability to cope with lasting side effects, said Ubel.
To my inexpert mind, the most obvious explanation is that doctors are probably less likely to sue each other (and are certainly less likely to sue themselves) than the average patient would be.  Curiously, the article doesn't even touch on the concept of "malpractice," yet I think fear of a lawsuit is one of the biggest reasons we have such an overly-cautious, over-MRI'ed, conservative, risk-averse (etc.) approach to medicine in America today.