Stress and Aggressive Breast Cancer: Cause or Effect?

Medical Author: Melissa Conrad Stöppler, MD
Medical Editor: Charles P. Davis, MD, PhD

A research study presented at the Fourth AACR Conference on the Science of Cancer Health Disparities in September 2011 revealed an association between psychological stress and one of the most aggressive types of breast cancer.

The study was performed on 989 women with breast cancer. Two to three months after diagnosis, the women were asked to rate their degree of anxiety, fear, and isolation. These self-reported stress scores were higher for black and Hispanic women than in white women. Further, those women who reported having higher levels of stress tended to have more aggressive tumors (defined as being negative for the presence of estrogen receptors, meaning that therapies designed to block the effects of estrogen will not be effective) than those with lower stress levels. The association between stress level and aggressive tumors was strongest in black and Hispanic women.

The major question, however, remains unresolved: Did the women's stress levels influence the tumors in any way, or is the heightened perception of stress a result of having been told that their tumor is of a more aggressive type? Because the women in the study were interviewed after their cancers were diagnosed, it is not possible to tell if they were indeed overly stressed prior to learning that they had cancer. It is also logical to assume that more aggressive tumors and more severe cases may provoke a greater degree of anxiety and fear in patients than less aggressive cancers that are more responsive to treatment. In addition, the study did not solve why white women had less stress than black or Hispanic women.

To clarify whether stress levels influence a tumor's aggressiveness, it would be necessary to interview women about their psychosocial stressors prior to their developing cancer, ideally over a period of years. Since most women do not develop breast cancer, a very large population of women would need to be interviewed, perhaps yearly, about their psychological stress levels. These women could be followed over a period of years, and those who develop breast cancer could be further studied to determine if high psychologically stressed women developed the most aggressive breast cancer types. Currently, there is no good data that psychological stress is a cause of the most aggressive types of breast cancer.