Doctors' and patients' preferences for participation and treatment in curative prostate cancer radiotherapy

Physicians hold opinions about unvoiced patient preferences, so-called substitute preferences. We studied whether doctors can predict preferences of patients supported with a decision aid.

A total of 150 patients with prostate cancer facing radiotherapy were included. After the initial consultation, without discussing any treatment choice, physicians gave substitute judgments for patients' decision-making and radiation dose preferences. Physicians knew that several weeks later, patients would be empowered by a decision aid supporting a choice between two radiation doses involving a trade-off between disease-free survival and adverse effects. Subsequently, patient preferences for decision making (whether or not they wanted to choose a radiation dose) and for treatment (low or high dose) were obtained. The chosen radiation dose actually was administered.

Of the patients studied, 79% chose a treatment; physicians believed that 66% of the patients wanted to choose. Agreement was poor (64%; = 0.13; P = .11), and was better as patients became more hopeful (odds ratio [OR] = 4.4 per unit; P = .001) and as physicians' experience increased (OR = 1.09 per year; P = .02). Twenty percent of physicians' preferences, 51% of physicians' substitute preferences, and 71% of patients' preferences favored the lower dose; agreement was again poor (70%; = 0.2; P = .03).

Physicians had problems predicting the preferences of patients empowered with a decision aid. They slightly underestimated patients' decision-making preferences, and underestimated patients' preferences for the less toxic treatment. Counseling might be improved by first informing patients-possibly using a decision aid--before discussing patient preferences.