Depression linked to lower survival rates in breast cancer patients, Markey study finds

A recent University of Kentucky Markey Cancer Center study reveals that having depression before or after a breast cancer diagnosis was associated with a lower likelihood of survival. The findings are published by Wiley online in Cancer, a peer-reviewed journal of the American Cancer Society.

For the study, Bin Huang, Dr.P.H., director of population-based cancer research at the Kentucky Cancer Registry, and his colleagues analyzed data from the Kentucky Cancer Registry to identify adult women diagnosed with primary invasive breast cancer from 2007–2011. Utilizing the health claims-linked cancer registry data, the team classified patients in one of the following categories: having no depression diagnosis, depression diagnosis only before cancer diagnosis, depression diagnosis only after cancer diagnosis, or persistent depression (defined as depression before and after cancer diagnosis). The team also assessed patients’ receipt of first course guideline-recommended treatment as indicated by the National Comprehensive Cancer Network breast cancer treatment guidelines.

Among 6,054 patients, 4.1%, 3.7%, and 6.2% of patients had persistent depression, depression pre-diagnosis only, and depression post-diagnosis only, respectively. Analyses indicated that 29.2% of patients did not receive guideline-recommended breast cancer treatment. Also, during a median follow-up of four years, 26.3% of patients died.

Compared with patients with no depression, patients with post-diagnosis only or persistent depression had a similar likelihood of receiving guideline-recommended treatment, but patients with depression pre-diagnosis only had 25% lower odds of receiving guideline-concordant care, although this finding was marginally significant. Additional research is needed to determine the potential reasons for this association. 

Depression pre-diagnosis only and depression post-diagnosis only (but not persistent depression) were linked with worse survival compared with no depression. Specifically, depression pre-diagnosis was associated with a 26% higher risk of death, and depression post-diagnosis was associated with a 50% higher risk. Also, patients who did not receive guideline-recommended treatment faced a 118% higher risk of death than those who received recommended care.

Compared with patients residing in non-Appalachian Kentucky, patients residing in Appalachia were 18% less likely to received recommended care, but investigators did not find any significant differences in survival.

The findings suggest that diagnosing and treating depression at the time of breast cancer diagnosis and beyond can be critical to patient care and survival. 

“A surprising result from this study is that patients with persistent depression did not experience worse survival compared with patients with no depression,” said Huang. “Given that under-diagnosis and under-treatment of depression are common among cancer patients, persistent depression could be an indication that patients’ depression may have been well managed. Hence, this particular result suggests the importance of depression screening and management throughout a cancer patient’s care.”

Huang noted that population-based cancer registry data enhance population-based cancer outcomes research.

“Utilizing linked health claims data and cancer registry data in this study demonstrated the value of data linkages across various sources for examining potential health disparities and identifying where improvements in cancer care are needed,” he said. “More rigorous studies are needed in depression management and across various cancer sites and patient populations. Subsequently, results from these research studies may further shape policies and guidelines for depression management in cancer care.”