Negative patient expectations are associated with an increased risk of treatment-related adverse events, nocebo side effects, and nonadherence to treatment in patients with breast cancer undergoing endocrine therapy, a study published in the journal Annals of Oncology has shown.1

For the 2-year prospective clinical cohort study, investigators enrolled 111 postoperative patients with hormone receptor-positive breast cancer receiving routine primary care and scheduled to begin adjuvant endocrine therapy.

Participants completed structured patient-reported assessments of side effects, side effect expectations, quality of life, and adherence during the first week postsurgery and after 3 and 24 months of endocrine therapy.

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Results showed that after 2 years of endocrine therapy, patients reported high rates of adverse events, including arthralgia (71.3%), weight gain (53.4%), and hot flashes (46.5%), as well as breathing problems (28.1%) and dizziness (25.6%) that were not directly attributable to endocrine treatment.

After controlling for relevant medical and psychological variables, researchers found that patient expectations prior to initiating endocrine therapy significantly predicted long-term adverse events and quality of life.

Specifically, patients with high negative expectations at baseline had an 83% (relative risk [RR], 1.833; 95% CI, 1.032-3.256) higher risk of experiencing adverse events after 2 years of endocrine treatment compared with those who had low negative expectations.

The study also revealed a significant association between baseline expectations and adherence to treatment after 2 years of treatment.

“Optimizing individual expectations might be a promising strategy to improve side-effect burden, quality of life, and adherence during longer-term drug intake,” the authors conclude.


1. Nestoriuc Y, von Banckenburg P, Schuricht F, et al. Is it best to expect the worst? Influence of patients’ side-effect expectations on endocrine treatment outcome in a 2-year prospective clinical cohort study. Ann Oncol. 2016 Aug 22. doi: 10.1093/annonc/mdw266. [Epub ahead of print]