In the largest study of its kind to date, Ohio State University researchers have shown that the stress women experience after breast cancer diagnosis and surgery can weaken their immune response, based on at least three different biochemical indicators.
The findings, reported in the January 7, 1998, issue of the Journal of the National Cancer Institute, are the latest in a series of studies documenting the link between conditions of high stress and low immunity.
Barbara Andersen, professor of psychology and a researcher at Ohio States Comprehensive Cancer Center and Institute of Behavioral Medicine Research, said that the results were the strongest evidence to date of a stress-linked immune reduction in cancer patients.
Three Indicators of Immune System Tested
Andersen and her colleagues studied 116 women who underwent surgery for stage II or III invasive breast cancer. Before the women began follow-up adjuvant therapy, they completed an extensive questionnaire intended to gauge their stress levels. Based on how they responded to the questionnaire, they were placed in either a high- or low-stress group.
Blood was drawn from women in both groups and tested for three different indicators of immune status. The first test measured the extent to which natural killer (NK) cells were breaking down. Andersens team also checked how well the NK cells responded to interferon-gamma. The researchers then tested how well the womens T-lymphocytes responded to phytohemagglutinin (PHA) and concanavalin A (Con-A), as well as to monoclonal antibodies.
Their analyses yielded the following findings:
- Compared with the low-stress group, 15.4% more of the NK cells in women in the high-stress group were destroyed.
- The response to interferon-gamma was 2.01% lower in the high-stress women than in the low-stress women.
- The T-cell response to PHA, Con-A, and the monoclonal antibodies was 19.8% less in the high-stress group than in the low-stress group.
I think this is the most reliable effect Ive seen so far in any of the scientific literature, Andersen said. And its occurred in the largest stress and immunity study so far thats focused on cancer patients.
Andersen said that this kind of study is very difficult to do. We were literally recruiting women on what they described as the worst day of their lives. Not only had they just had surgery but theyd also been told they had positive nodes, cutting their prospects for survival in half, Andersen said.
The new findings are the first real results from Andersens 6-year, $4.2 million project. The study was funded by the National Institute of Mental Health and the Department of the Army. Initial grant support came from the American Cancer Society.
The study will eventually involve 235 breast cancer patients, Andersen said, and will include additional testing of other immune system components. A comparable report citing changes in hormone levels key to immune response is expected later next year.
Andersen and her colleagues are also randomly assigning women in the study to one of two groups. The women in the first group will only be monitored and assessed for stress levels, while those in the second group will be taught strategies for lowering their stress levels, improving their diets, and increasing their levels of exercise. At the end of 6 years, the researchers will compare the immune and endocrine responses, health, and survival of women in the two groups.
Other members of the research team included William Farrar, associate professor of surgery; Robert MacCallum, professor of psychology and preventive medicine; Ronald Glaser, professor of microbiology and immunology and of internal medicine; Deanna Golden-Kreutz, project coordinator; Leigh Ann Kutz, laboratory technician, and Mary Elizabeth Courtney, a research associate.