Core Outcome Set Measures Are Underreported in Breast Cancer Randomized Clinical Trials: A Cross-Sectional Study

Randomized controlled trials (RCTs) are the gold standard in oncology for the discovery of new therapeutic approaches and treatment management. As medicine takes a more patient-centered approach, patient-reported outcomes (PROs) have become imperative, particularly in clinical trials. The need for standardization of PROs in research led to the development of the International Consortium for Health Outcomes Measurement (ICHOM). ICHOM has published literature describing its methodology and the development of a breast cancer core outcome set (COS). Our primary aim was to investigate the completeness of reporting within breast cancer clinical trial registries after the publication of the ICHOM breast cancer COS.

A cross-sectional analysis was performed using the ClinicalTrials.gov database. COS information and trial characteristics were extracted from the trial registries in a masked manner. The completeness of reporting of the COS was analyzed.

After our final inclusion criteria were applied, our final sample of 237 RCTs was assessed. Systemic therapy was the most commonly reported type of intervention (216/237; 91.1%). The average completeness of reporting was only 28.5% across all of the intervention types, and over three-fourths of the RCTs reported less than half of the COS measures.

As PROs and patient-centered healthcare are coming to the forefront of medicine, particularly in oncology, a standardized COS, like ICHOM's, offers trialists an endorsed resource to thoroughly capture and report the patient perspective in clinical research. We have offered recommendations to improve the reporting of PRO measures to capture within breast cancer RCTs.