Consequences of Late Effects

The impact of schizophrenia on breast cancer mortality: a nationwide population-based cohort study in Denmark

In Denmark breast cancer treatment is standardized through the protocols administered by the Danish Breast Cancer Coorporative Group in order to ensure high and equal standard of breast cancer management on a population basis.

However, a number of women are not able to in all cases enroll in these protocols and thus to a lesser degree will receive standardized treatment. One such group include women with severe psychiatric disorders.

The objective of this study is to compare overall and breast cancer specific mortality in breast cancer patients with and without schizophrenia and related disorders. We will use Danish national registries to identify all women diagnosed with breast cancer 1995–2011. We will investigate the likelihood for receiving a protocolized breast cancer treatment among women with schizophrenia and related disorders and further, compare survival rates for overall and breast cancer specific mortality both among populations following a protocol and for those who did not receive a standard treatment.

This study will contribute to our knowledge in regard to cancer outcomes in a vulnerable population group.

Mortality after breast cancer among women treated for depression: a Danish nationwide cohort study

We will investigate if women treated for depression before diagnosis of breast cancer have higher mortality, increased risk for metastasized disease at diagnosis and increased risk for not being allocated to protocolized breast cancer treatment.

In Danish nationwide registers we identified all 47,130 women diagnosed with breast cancer in Denmark 1998–2011 as well as individual information on education, cohabitation, comorbidity and detailed clinical information on breast cancer and treatment.

We defined previous treatment of depression as hospital contacts with depression and/or use of antidepressants prior to diagnosis of breast cancer and used multivariate logistic regression to assess if women treated for depression had increased risk for metastasized breast cancer at diagnosis and not being allocated to protocolized breast cancer. Multivariate Cox regression analyses were used to compare all-cause and breast cancer-specific mortality after breast cancer between women treated and not treated for.

Women treated with antidepressants before diagnosis of breast cancer were less likely to have metastasized breast cancer at diagnosis, however had increased risk for not being allocated to protocolized breast cancer treatment.

Further, among 39,404 women diagnosed with non-metastasized breast cancer who were allocated to protocolized breast cancer treatment, we found that women treated with antidepressants had significantly increased all-cause (HR 1.26, 95% CI 1.16-1.36) and breast cancer-specific (HR 1.18, 95% CI 1.07-1.30) mortality after breast cancer.

Women treated for depression before breast cancer had increased risk for not receiving protocolized breast cancer treatment and further, independently of this, had increased all-cause and breast cancer-specific mortality.