Breast Cancer Treatment Disparities in Patients with Severe Mental Illness: A Systematic Review and Meta-Analysis

Abstract

Background Disparities in breast cancer treatment for people with pre-existing severe mental illness (SMI) have not been well studied compared to disparities in cancer screening and stage at diagnosis.

Aims To conduct a systematic review of the available evidence and investigate whether female breast cancer patients with pre-existing SMI had equitable access to guideline recommended breast cancer treatment compare to those without SMI.

Methods We conducted systematic review and meta-analysis of observational studies that were retrieved from PubMed, EMBASE, CINAHL and PsycINFO databases from 22 February 2021 to 26 March 2021. Female breast cancer patients with SMI were included in the analyses. SMI was defined as Schizophrenia, Bipolar disorder, and major depression. Guideline recommended treatment was defined as surgery, chemotherapy, radiotherapy and adjuvant endocrine therapy. Pooled odds ratios, and other estimates, such as hazard ratios and risk ratios were presented. Risk of bias was assessed using Newcasle-Ottawa scale. DerSimonian-Laird random effects models were used.

Results 3,325 citations were identified; 10 studies were included, and 4 studies were meta-analysed. Pooled analyses suggested that people with SMI were less likely to receive guideline recommended breast cancer treatment than those without SMI (OR: 0.83; 95% CI: 0.77 to 0.90). Breast cancer patients with schizophrenia had a reduced likelihood for receiving adjuvant radiotherapy (Crude RR: 0.81, 95% CI: 0.77 to 0.85), while those with major depression and bipolar I disorder had lower likelihood of receiving adjuvant chemotherapy (Crude RR: 0.71, 95% CI: 0.60 to 0.84).

Conclusions This review identified disparities in breast cancer care for individuals with pre-existing SMI, which contributed to poorer prognosis and excess mortality. Improving collaboration between psycho-oncology teams is advised to address patients’ needs for treatment. Future research is necessary for identifying disparities in primary and systemic treatments and investigating the reasons for treatment inequity.