Could Depression Increase All-Cause Mortality Risk in Breast Cancer Patients?

A team of researchers from King’s College London have found that women with breast cancer who subsequently received a depression diagnosis were at a 45% greater risk of all-cause death.

The investigators evaluated the cancer registration and hospital records of 77,173 women in South East England. The authors followed the participants, all of whom had been diagnosed with breast cancer between the years 2000 and 2009, until the end of 2010. Overall, 422 of these patients already had a recorded history of depression before receiving a breast cancer diagnosis, and 533 were diagnosed with depression after learning they had breast cancer.
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The team found that the connection between a new diagnosis of depression and survival was still evident after accounting for factors such as older age at cancer diagnosis, the degree of cancer advancement at the time of diagnosis, socioeconomic status, and the presence of other diseases.

After taking these variables into consideration, the relative risk of death over the follow-up period was 1.45 times, or 45%, higher than in women without recorded depression in that time, according to the authors, who note that the decreased survival of women with depression could be linked to an impact on cancer progression or to other effects of depression that increase death risk. In total, 55% of all participants with recorded depression were still alive 5 years after receiving their breast cancer diagnosis, while 75% of those without recorded depression were still alive after 5 years had passed.

Elizabeth Davies, PhD, MSc, a clinical reader in cancer studies and public health sciences at King’s College London, and a co-author of the study, notes that the medical notes analyzed in this study may not be complete, and that less severe depression may not necessarily be entered into hospital records in all cases.

Davies adds, however, that previous research has found “women who have had previous episodes of depression are likely to be most at risk of depression after a cancer diagnosis.”

Family physicians, who “generally have more prior knowledge of women and their situations,” she says, “are also well-placed to assess and support affected women.”

—Mark McGraw

Reference

Kanani R, Davies E, et al. The association of mood disorders with breast cancer survival: an investigation of linked cancer registration and hospital admission data for South East England. Psycho-Oncology. 2015.