Reporting of older subgroups in registration breast cancer trials 2012-2021

Adequate reporting of data specific to older populations enrolled to breast cancer trials is critical, given the high incidence of the disease among this demographic. This study aimed to examine the completeness of reporting of older subgroups among patients recruited to registration clinical trials investigating systemic treatments for breast cancer.

Clinical trials leading to a US food and drug administration (FDA) approval in breast cancer between 2012 and 2021 were included. Primary study reports and and all available secondary publications were systematically and objectively assessed with regard to the availability of data regarding efficacy, baseline characteristics, safety, and health-related quality of life (HRQOL) outcomes among older subgroups.

27 trials and 216 publications were assessed. 20.3% of patients were aged ≥65. 70.0% of patients had an eastern cooperative oncology group (ECOG) performance status of 0. Although complete reporting of primary endpoints was adequate (72.7%), most protocol-defined primary endpoints were surrogate endpoints (84.8%). Overall survival data among older populations was unavailable in 50.0% of studies. Reporting was poor for secondary efficacy endpoints (81.8% unreported), baseline characteristics (70.4% unreported), toxicity (55.6% unreported), and health-related quality of life outcomes (87.5% unreported).

The findings underline significant deficits in the reporting of age-specific data in breast cancer registration trials. The underreporting of key efficacy, safety, and HRQOL outcomes highlights the need for mandatory reporting standards and a dedicated emphasis on older populations' priorities and needs in the reporting of registration clinical trials.