Cancer care treatment attrition in adults: Measurement approaches and inequities in patient dropout rates - a rapid review.

BACKGROUND

Cancer treatment attrition refers to the discontinuation of prescribed cancer therapies before completion. It can significantly impact patient outcomes and cancer survival rates making it a critical concern. There is growing evidence on inequalities in cancer care, the avoidable systematic differences in the health of different groups of people. Understanding the extent of treatment attrition, why it happens, for whom, and associated inequalities may improve cancer care delivery and patient outcomes.

METHODS

A rapid review was conducted to identify existing evidence on measures of cancer treatment attrition, definitions, reasons for attrition and potential inequalities. The review followed a systematic approach but with abbreviated processes to facilitate quicker evidence synthesis. Searches were restricted to MEDLINE and Embase databases from their inception dates to May 7, 2024. Additional searches were performed in PubMed, Google Scholar, and key grey literature from relevant organizations. Inclusion criteria were adults with any type of cancer undergoing treatment, with studies reporting quantitative or qualitative data on treatment attrition conducted outside of clinical trials. Exclusion criteria included studies on children or adolescents, clinical trials, non-English publications, and various non-research article types. Data extraction and quality assessment were performed using standardized tools, and studies were synthesized narratively.

RESULTS

The search retrieved 1,353 references, with 40 studies meeting inclusion criteria. Most studies were retrospective. Studies covered various cancer types and treatments, reporting measures of attrition and reasons for treatment drop-out. Factors influencing attrition included disease progression, death, clinical deterioration, treatment toxicity, and socioeconomic factors such as lower income or socioeconomic disadvantage.

CONCLUSIONS

This review highlights significant variability in how treatment attrition is measured and defined, and suggests potential inequalities in who discontinues treatment. Standardized measures of attrition and data collection on reasons for discontinuation are essential to improve cancer care outcomes and equity. Future research should focus on developing these standardized metrics and exploring interventions targeting identified disparities to support cancer patients to complete treatment and improve outcomes.