Variations in time to breast cancer treatment initiation and survival across ethnoracial groups: a DAG-based protocol for a systematic review and meta-analysis

Abstract

Abstract Background Racial disparities in access to care are a known driver of differential health outcomes. There is a need to synthesize knowledge on the impact and mechanisms of ethnoracial variations in initiation of breast cancer treatment. The aim of the study described in this protocol is to systematically review the existing evidence on ethnoracial disparities in initiation of breast cancer treatments and their impact on patients’ survival in the United States. Methods A comprehensive systematic search of databases including PubMed, Ovid, Web of science, and the Cochran library will be performed. An extra search filtered on the title will be carried out on Google Scholar. Two main keywords, ‘breast cancer’ and ‘time to treatment,’ will be used in search strings. The review process will follow Preferred Reporting Items for Systematic Review and the Meta-Analysis Protocols (PRISMA-P) guidelines and will include studies of cohorts of female breast cancer patients who were diagnosed with stage I-III in the US. The Risk Of Bias In Non-randomised Studies – of Interventions (ROBINS-I) tool will be applied for bias assessment, and only studies with low or moderate risk of bias will be included. A modified checklist for applying the Evidence synthesis for constructing directed acyclic graphs (ESC-DAGs) method is developed to describe the causal relationships between ethnoracial group membership, other study variables, delays to treatment, and survival. Discussion This systematic review will summarize the impact of racial disparity on breast cancer survival considering delays in receiving treatments as a mediator. Future directions will be identified to address existing gaps potentially relevant to creating equity for racial and ethnic minority groups. The results can help health authorities to develop approaches for addressing racial disparities in access to breast cancer treatment at the population level.