The combination of shortened telomeres, a biological marker of aging associated with cancer development, and elevated depression significantly impacted bladder cancer mortality, according to data presented at the 11th Annual AACR International Conference on Frontiers in Cancer Prevention Research, held here Oct. 16-19, 2012.
"We found that patients with bladder cancer with shorter telomeres and high levels of depression symptoms have a threefold increased risk for mortality," said Meng Chen, Ph.D., an epidemiologist at The University of Texas MD Anderson Cancer Center in Houston.
As part of an ongoing, large-scale epidemiologic study of bladder cancer, Chen and colleagues collected clinical and mental health information on 464 patients with bladder cancer. They assessed patients' depression levels with the Center for Epidemiologic Studies Depression Scale (CES-D).
Depression symptoms alone affected mortality: Patients with CES-D scores of 16 or greater had a median survival time of 58 months, while those with scores below 16 had a median survival time longer than 200 months. In addition, patients with CES-D scores of 16 or greater had a 1.89-fold increased risk for all-cause mortality compared with patients with CES-D scores less than 16.
Telomere length was measured from patient blood samples. Univariate analysis revealed that long telomeres were associated with improved survival, but this finding was not significant in a multivariate analysis.
When evaluating the combination of depression and telomere length, the researchers found that compared with patients without depression symptoms (i.e., CES-D scores less than 16) and long telomeres, patients with depression symptoms (i.e., CES-D scores of 16 or greater) and short telomeres demonstrated more than a threefold increased risk for mortality and significantly shorter disease-free survival (31.3 months versus 199.8 months).
Although the mechanisms behind these findings need to be furthered studied, "these results suggest the potential important role of psychological factors to improve survival in cancer patients," Chen said.
In addition, the researchers pointed to evidence that smoking cessation, weight loss and increased physical activity can slow telomere shortening and potentially improve survival.
"In terms of building a prediction model for bladder cancer mortality, current models only focus on clinical variables, such as treatment and tumor stage and grade," Chen said. "Our study suggests that psychological factors and perhaps lifestyle changes could be included in this prediction model."