According to researchers, low depressive symptoms and a longer telomere length are compelling factors that contribute to a prolonged life for bladder cancer patients. The researchers are from The University of Texas MD Anderson Cancer Center.
In an observational study, a team of MD Anderson researchers analyzed clinical and behavioral data collected from 464 bladder cancer patients, according to research presented at the 11th Annual AACR International Conference on Frontiers in Cancer Prevention Research.
"This is the first study of its kind that analyzes bladder cancer outcomes," said Meng Chen, Ph.D., an instructor in MD Anderson's Department of Epidemiology. "Psychological factors are not usually included in epidemiologic studies"
The patients observed were enrolled in an ongoing study of bladder cancer that provides extensive genetic, epidemiologic and psychological data. The collaboration of MD Anderson epidemiologists and psychologists is led by the study's principal investigator, Xifeng Wu, M.D., Ph.D., professor and chair of the epidemiology department.
Patients' information was analyzed according to four different groups. The first group involved patients with long telomeres and no depressive symptoms; the second identified patients who had long telomeres with depressive symptoms; the third had shortened telomeres and no depressive symptoms, while the fourth group had shortened telomeres and depressive symptoms.
Bladder cancer is the fourth most common cancer of men and is usually diagnosed in people over the age of 60. The American Cancer Society estimates 56,000 men and 18,000 women will have a bladder cancer diagnosis in 2012.
Research has identified shortened telomere length as an aging-associated biomarker in several diseases, including cancer. As people grow older, telomeres on the tips of chromosomes, which protect chromosomes from unraveling as cells replicate, shorten and eventually fail, leading to cell death. MD Anderson researchers analyzed blood samples to measure telomere length.
Depressive symptoms were analyzed using the Center for Epidemiologic Studies Depression Scale (CES-D). The self-report scale - one of the most common screening tests used for finding levels of depression - revealed patients who scored at high levels of depressive symptoms have a 1.89-fold risk of dying compared to those with lower levels of depression, who will live a little over three times longer - 200 months vs. 58 months.
The study also revealed the combination of factors, longer telomeres and low levels of depressive symptoms, increased survival for bladder cancer patients by more than six-fold - 31.3 months vs 199.8 months. Those with short telomeres and high levels of depression had a three-fold risk of mortality.
A certain level of stress, which has also been associated with shortened telomere length, is a dominating factor with many cancer patients. "People are not treating the depression directly, but mainly focused on coping with cancer,"said Chen. "This leads to additional stress that increases mortality."
Enhanced stress management should be an integral part of cancer treatment, "Lifestyle behaviors including a healthy diet, regular exercise and smoking-cessation are factors for reducing stress and ultimately depression in cancer patients"." said co-author Jie Lin, Ph.D., assistant professor in the Department of Epidemiology.
Lin also said the new risk factors such as psychological risk factors identified by the team could be included in future risk prediction models. The team is optimistic that this study will encourage clinicians to incorporate behavioral factors into risk models so interventions can be developed to prolong survival for bladder cancer patients.