Overlooked and underreported: A systematic review of quality of life in recent Phase III metastatic breast cancer trials

Abstract

Background

In metastatic breast cancer (MBC), where treatment is non-curative, patient quality of life (QoL) is a critical consideration alongside traditional survival outcomes. Despite increasing recognition by regulatory bodies, the extent of QoL incorporation into contemporary Phase III trials remains unclear.

Methods

We conducted a systematic review of Phase III randomized controlled trials evaluating therapeutic interventions for MBC published between 2019 and 2023, using the PubMed database. Trials were categorized based on receptor subtype (HR+, HER2 +, TNBC), trial design (superiority vs. non-inferiority), study outcome (positive vs. negative), and journal impact factor. The primary outcome was the incorporation of QoL outcomes in published results.

Results

Among 122 eligible trials, only 36.9 % included QoL measures. Subgroup analysis revealed higher QoL incorporation in hormone receptor-positive trials compared to HER2 + and TNBC subtypes. Non-inferiority trials were more likely to include QoL endpoints (50 %) than superiority trials (33.7 %). QoL reporting was higher in negative studies (45 %) compared to positive studies (33 %), with no significant difference based on journal impact factor.

Conclusion

Despite regulatory emphasis on patient-centered outcomes, QoL assessments remain underreported in publications of Phase III MBC trials. Standardized incorporation of QoL metrics is essential to better capture the holistic impact of therapies, improve clinical decision-making, and align oncologic research with patient priorities.