Doctors making treatment decisions often misinterpret patients' preferences, such as overestimating how much priority women with cancer place on keeping their breasts, a new review finds.

A doctor can't recommend the right treatment without understanding how the patient values trade-offs, researchers said in this week's British Medical Journal.

Authors offered physicians three steps to ensure patients' preferences aren't misdiagnosed. (IStock)

In one study, doctors believed that 71 per cent of breast cancer patients rated keeping their breasts as a top priority, but only seven per cent said so.

In another example, people with dementia placed much less value than doctors believed on continuation of life with severely declining cognitive function.

More than a century ago, Canadian Dr. William Osler urged medical students to "listen to the patient: he is telling you the diagnosis."

The rise in accuracy of diagnostic tests has allowed doctors to rely less on listening when determining the cause of symptoms, but listening is more important than ever when deciding which treatment option best fits each patient's priority, said Albert Mulley of the Dartmouth Center for Health Care Delivery Science in Hanover, N.H., and his co-authors.

"A preference misdiagnosis is a silent misdiagnosis," they wrote.

Study authors' advice for doctors

The authors offered physicians three steps to ensure patients' preferences aren't misdiagnosed:

• Adopt a mindset of scientific detachment, resisting the instinct to ask themselves, "What would I do in this situation?" because the patient may value the risks, benefits, and side-effects of the treatment options differently.
• Form a provisional diagnosis based on available data on what a patient’s preference is likely to be, without assuming that the patient in front of them is the "average" patient.
• Engage patients in shared decision-making by informing them of the options; discussing the risks, benefits, and side-effects of each, including non-treatment options like watchful waiting; and inquiring if they feel ready to make a decision.

Patients who become better informed frequently change their decisions, the authors noted. For example, a randomized trial of a decision aid (tools such as videos or posters) for coronary heart disease in Toronto showed reduction in preference for surgical treatment for patients with stable angina.

By observing how patients react when presented with each possible course of action, doctors can gather information on their preferences, the authors suggested.