Depression may explain why some older men don’t seek treatment for prostate cancer, even after receiving diagnoses.

As many as 200,000 men in the United States received prostate cancer diagnoses in 2010, according to the Centers for Disease Control and Prevention. That year, another 30,000 died of the disease. At least some of those deaths were preventable, as mental illnesses such as depression hampered men from either seeking treatment or following the recommended treatment for their particular stage of cancer, researchers from the University of California at Los Angeles said.

“We traditionally think of disparities in health care by race and socioeconomic status, but our research demonstrates that mental illness can also be a significant driver of treatment choice and outcomes in terms of prostate cancer,” researcher Jim Hu told Reuters. His study appeared in the Journal of Clinical Oncology.

Past research has found associations between depression among cancer patients, and a greater chance of receiving inadequate treatment, leading to worse outcomes. In studying the effect on older men with prostate cancer, Hu and his colleagues focused on 1,894 Medicare patients who had been diagnosed with localized prostate cancer between 2004 and 2007, and had also been diagnosed with depression during the two years prior to their cancer diagnoses.

Hu said the findings describe a vulnerable population among older adults suffering multiple health problems. “First, we found that men with prostate cancer who were older, lower income, with more medical [conditions], white or Hispanic [versus Black and Asian], unmarried, residing in non-metropolitan areas were more likely to be depressed,” Hu said. “In addition, depressed men were less likely to seek out definitive therapy [such as surgery or radiation] in contrast to non-depressed men."

Yet, however problematic depression may be in a person’s life, Hu said the findings surprised him given that depressed men were much more likely than others to have seen a doctor prior to receiving a cancer diagnosis — averaging 43 visits compared to 27 visits, respectively. Moreover, prostate cancer outcomes were worse for depressed men even after considering differences in tumor characteristics and choices in treatment, with a lower survival rate. Depressed men were also more likely to choose a lower tier of treatment, including hormones, or to decline treatment entirely.

Source: Prasad S, Eggener S, Lipsitz S, et al. Effect of Depression on Diagnosis, Treatment, and Mortality of Men With Clinically Localized Prostate Cancer. Journal of Clinical Oncology. 2014.