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.