Breast cancer patients on endocrine therapy reveal more symptoms when self-reporting than in pivotal trials: an outcome research study.

Objectives: The purpose of this investigation was firstly to assess the overall frequency of subjectively experienced symptoms self-reported by patients receiving endocrine therapy and secondly to compare these symptoms with side effects assessed by clinicians in pivotal trials.

Methods: Unselected patients with early and advanced breast cancer receiving endocrine therapy were approached consecutively during a routine outpatient visit. They received a questionnaire called Checklist for Patients with Endocrine Therapy (C-PET), a validated self-assessment tool to determine prespecified symptoms associated with endocrine therapy.