A new study funded by the National Cancer Institute reports that social support and other behavioral factors are related to levels of a circulating protein, which at high levels is associated with a poor prognosis in advanced ovarian cancer.
The study, published in the July 15, 2005 issue of CANCER, a peer-reviewed journal of the American Cancer Society, reports that factors that improved quality life, such as social support, were associated with low levels of a protein released by both immune cells and tumor cells, called interleukin 6 (IL-6). In contrast, negative quality of life factors were associated with higher IL-6 levels.
The study is the first to find this association both in the peripheral blood and in the vicinity of the tumor.
IL-6 is an inflammatory cytokine that in healthy young people is almost undetectable. Levels of IL-6 increase with age, chronic psychological stress, and disease. Previous studies in humans and laboratory animals have shown IL-6 levels are also influenced by behavioral factors.
IL-6 has previously been shown to promote tumor growth, and IL-6 levels are also prognostic in ovarian cancer, with elevated levels associated with higher mortality and metastatic disease. Because depression and chronic stress are commonly associated with ovarian cancer, and IL-6 levels are responsive to psychosocial factors, Erin S. Costanzo, M.A. from the University of Iowa and colleagues investigated whether IL-6 levels were linked to psychosocial factors in 61 women with advanced ovarian cancer.
While levels of IL-6 and the incidence of depression were elevated in these patients, those who reported strong social attachments had significantly lower levels of IL-6 in both the blood and in the ascites fluid surrounding the tumor. Women with weak social attachments had 1.7 times more IL-6 in the circulating bloodstream and 2.5 times more in the ascites fluid surrounding the tumor than women with strong social attachments. Higher levels in the bloodstream were also found among women who reported poor quality of life, such as fatigue and decreased physical function.
The investigators conclude, that "the finding that social attachment is strongly related to IL-6 not only in the periphery but also in the vicinity of the tumor suggests that psychosocial factors may indeed be important clinically" in the course of ovarian cancer.