STRESS AND PROSTATE CANCER MORTALITY

NEW YORK (Reuters Health) - High levels of perceived stress and lack of social support were associated with higher mortality rates among men with prostate cancer, in a study presented February 20 at the annual meeting of the American College of Preventive Medicine in New Orleans.

Researchers analyzed data from 4,105 prostate cancer patients participating in a national follow-up study in Sweden. They had been diagnosed with localized prostate cancer between 1997 and 2002. All were less than 70.

The men were asked to complete Cohen's Perceived Stress Scale, a 14-item questionnaire that asks responders to assess the degree to which various life situations are considered stressful. Their responses were then added together to produce a total perceived stress score. They were also asked questions about the loss of loved ones, difficulty sleeping, and their ability to talk about emotional problems with partners, friends, and family.

Emotional and behavioral factors such as grieving, poor sleep and lack of emotional support were more common among those with higher levels of perceived stress.

During a mean follow-up of 51.3 months after the questionnaires were returned, there were 127 prostate cancer deaths (3.1%) and 276 deaths from other causes (6.7%). Men in the highest tertile of perceived stress had a 66% increased risk of prostate cancer-specific mortality compared to men in the lowest tertile. A sensitivity analysis was performed to ensure that this finding was not biased by rapidly deteriorating health and/or hastened mortality. After excluding men who died of prostate cancer within six months of responding to the questionnaire, the result did not change.

"This is an important study that shows that the perceived impact of stress is associated with survival in prostate cancer," observed Dr. Frank Penedo, Director of the Cancer Survivorship Institute at Northwestern University's Robert H. Lurie Comprehensive Cancer Center. "The next question is what mechanisms link this perceived stress to disease progression and mortality?"

Michael Jan, the lead researcher and an MD/PhD candidate at Temple University School of Medicine, agreed that this is an important next question.

"Our main finding that high stress is associated with increased prostate cancer-specific mortality agrees with a biological mechanism demonstrated in animal models, Jan said. "A group at Wake Forest found that stress actually increases proliferation of prostate cancer cells compared to other cell types in mice. Our study obviously didn't go into the molecular biology of our participants, but there is biological evidence to support our claim of a relationship between stress and prostate cancer."

Dr. Penedo suggested, "We could be seeing evidence of the physiologic impact of stress, such as inflammation and tumor progression, or there could be behavioral factors connected to stress, such as compliance with treatment guidelines and follow up, or we may need to look deeper into comorbid conditions, access to care and socioeconomic status to determine everything that is playing a role here."

Jan added that regardless of the underlying mechanism, he hopes these findings encourage health care practitioners to work harder to identify prostate cancer patients who might benefit from individualized attention to and programs that address stress reduction, sleeping habits, and social support.