The shorter survival times may be attributed to higher quantities of the stress hormone cortisol and inflammatory gene expression, said the researchers from the University of Texas.
"Our findings, and those of others, suggest that mental health and social well-being can affect biological processes, which influence cancer-related outcomes," said Professor Lorenzo Cohen in a university news release.
The findings "also suggest that screening for mental health should be part of standard care because there are well-accepted ways of helping people manage distress, even in the face of a life-threatening illness," Cohen added.
For the study, researchers analysed surveys completed over a five-year period by 217 patients newly diagnosed with advanced kidney cancer. The survey included questions about participantsí religion and spirituality, and also asked about symptoms of depression, social support, quality of life and coping skills.
The patients also provided blood and saliva samples that the researchers used to track changes in the patients' levels of cortisol (a stress hormone).
The average survival rate was 1,8 years after diagnosis, and by the time of the analysis, 64 percent of the patients had died.
The study revealed that 23 percent of patients were clinically depressed, and the investigators noted that depression was associated with shorter survival time. Moreover, the study showed that higher than usual cortisol levels were also linked to shorter survival among the cancer patients.
Using tissue samples from 15 of the patients with the most significant symptoms of depression and 15 samples from the patients with the mildest forms of depression, the researchers then conducted whole-genome profiling to determine if the depression is linked to increased risk of death for cancer patients.
They found specific signalling pathways, which play a key role in regulating cell inflammation, were expressed at increased levels in patients with depression. The study authors concluded the link between patients' mental health and survival time is associated with inflammatory gene regulation.
"Our findings indicate that we're now able to understand some of the possible biological pathways that explain the association between depression and survival," Cohen noted.
Source: HealthDay News