Elderly patients with breast cancer who also have preexisting mental illnesses may experience an increase in all-cause mortality, according to a study published in The Journal of Clinical Oncology.

For this retrospective cohort study, investigators analyzed the data collected from 19,028 women with breast cancer who were older than 67 years with stage I to IIIa breast cancer. Patients were identified as mentally ill if they had a prior diagnosis of bipolar disorder, schizophrenia, or other psychotic disorder based on the International Classification of Diseases, Ninth Edition.

Patients with mental illness were followed for up to 5 years after a breast cancer diagnosis, at which point they were compared with patients without breast cancer to evaluate survival outcomes.

Of the patients in the study, nearly 3% were found to have preexisting severe mental illness. The all-cause mortality hazard was approximately doubled in patients with severe mental illness compared with those who had no mental illness, after adjusting for age, income, ethnicity, geographic location, and marital status (adjusted hazard ratio [aHR], 2.19; 95% CI, 1.84-2.60). An insignificant increase of 20% in breast cancer-specific mortality was observed (aHR, 1.20; 95% CI, 0.82-1.74).

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Patients with severe mental illness also reported increased rates of tobacco usage and comorbidities, and were also more likely to have aggressive tumor characteristics and advanced breast cancer, perhaps due to a delay in diagnosis.

The study authors concluded that “More research is needed to determine models of coordination that work best to improve outcomes among patients with severe mental illness and to further elucidate the causal pathways between mental illness and reduced survival among patients with breast cancer. An understanding of how factors such as care use and quality and treatment decisions influence outcomes in this vulnerable population can help to inform changes in clinical practice.”

Reference

1. Iglay K, Santorelli L, Hirshfield KM, et al. Impact of preexisting mental illness on all-cause and breast cancer–specific mortality in elderly patients with breast cancer [published online September 21, 2017]. J Clin Oncol. doi: 10.1200/JCO.2017.73.4947