Research on psychological interventions for cancer patients is expanding to include important new outcome variables, but is hobbled by the fact that research samples are mainly limited to white women with breast cancer, notes Barbara L. Andersen, PhD, of The Ohio State University in a literature review in this month's Journal of Consulting and Clinical Psychology (JCCP).
The article updates a 1992 review in JCCP (Vol. 60, No. 4), also by Andersen, that looked at quality-of-life and stress outcomes in these interventions. The new review also includes new outcome variables such as health behaviors and disease outcomes, reflecting an expanded theoretical model of cancer stress and disease course called the biobehavioral model.
She concludes that:
Research on psychological interventions is scanty on men, low-income people and people of color who have cancer. "Without increasing diversity, the field is at risk of characterizing intervention outcomes for only middle-age, middle-class women with cancer," Andersen writes.
Psychological interventions produce significant reductions in distress, but their effects may be transitory.
It's difficult to draw general conclusions about the efficacy of such interventions because the intervention strategies are so diverse. Relatedly, researchers need to pay more attention to patient and intervention variables so they can better compare effects across studies.
Interventions that target diet and exercise appear very effective in getting cancer patients to improve their eating and exercise patterns.
Exercise-intervention studies are starting to suggest important health outcomes as well. In a study of bone-marrow transplant patients, for example, patients who joined an exercise program showed better clinical measures and shorter hospital stays than those who didn't exercise.
Two novel, inexpensive and effective interventions for cancer patients point the way for future research. In one, physicians were briefly trained to listen, convey warmth and provide feedback to patients. Patients of these physicians showed less anxiety and depressive symptoms and more satisfaction and sense of personal control than controls whose physicians didn't receive the training, the study found. In another study, patients received either a brief orientation to a medical oncology clinic or not. A week later, intervention patients reported less anxiety, less mood disturbance and fewer depressive symptoms than controls.
With few exceptions, cancer patients in studies that included immune and other biologic measures showed no improvements on these measures as a result of psychological interventions. The reasons for this, Andersen speculates, is that this research is extremely difficult and costly to conduct, leading to a range of methodological difficulties such as high attrition among participants for whom extra blood tests may be too burdensome. "We have to decide very carefully what samples we can do this research on and do a great job of it so we don't spend money and lose half our sample," Andersen comments.
Andersen also concludes that, in general, researchers would do well to identify and include in future research design specific characteristics of cancer patients, including socioeconomic status, predisease conditions and individual differences such as coping strategies and tendency toward optimism. This level of precision will make findings clearer and more meaningful, Andersen says.