Long-term health outcomes of a decision aid: data from a randomized trial of adjuvant! In women with localized breast cancer

Abstract

Purpose: Women with localized breast cancer face difficult decisions about adjuvant therapy. Several decision aids are available to help women choose between treatment options. Decision aids are known to affect treatment choices and may therefore affect patient survival. The authors aimed to model the effects of the Adjuvant! decision aid on expected survival in women with early stage breast cancer.

Patients and methods: Data were obtained from a randomized trial of Adjuvant! (n = 395). To calculate the effects of the decision aid on survival, the authors used the Adjuvant! survival predictions as a surrogate endpoint. Data from each arm were entered separately into statistical models to estimate change in survival associated with receiving the Adjuvant! decision aid.

Results: Most women (approximately 85%) chose a treatment option that maximized predicted survival. The effects of the decision aid on outcome could not be modeled because a small number of women (n = 12, 3%) chose treatment options associated with a large (5%-14%) loss in survival. These women-most typically estrogen receptor positive but refusing hormonal therapy-were equally divided between Adjuvant! and control groups and were not distinguished by medical or demographic factors.

Conclusions: Expected benefit from treatment is a key variable in understanding patient behavior. A small number of women refuse adjuvant treatment associated with large increases in predicted survival, even when they are explicitly informed about the degree of benefit they would forgo. Investigation of the effects of decision aids on cancer survival is unlikely to be fruitful due to power considerations.

Figure 1

Difference between groups in predicted outcome of treatment choice by maximum benefit. Light gray lines indicate 95% confidence intervals.