The theory that there is a "cancer personality" that increases breast cancer risk and reduces survival has been circulating in popular culture for more than two decades. Books such as The Type C Connection: The Behavioral Links to Cancer and Your Health (1992) have been followed by more recent books such as Healing the Cancer Personality (2013) which serve to perpetuate the theory. However, researchers for the most part have found no significant associations between personality traits and breast cancer risk. Now a new study has found no link between five relevant personality traits and the risk of various cancers, including breast cancer.

There is no cancer personality

As noted above, the theory that there is a cancer personality that predisposes women to breast cancer has not been borne out in the numerous studies that have been undertaken to study it. The following personality traits have been ruled out as contributing to the risk of developing breast cancer:

  • Depression
  • Emotional repression
  • Chronic anxiety
  • Neuroticism
  • Introversion or extraversion
  • Anti-emotionality (an absence of emotional behavior or a lack of trust in one’s own feelings)
  • Anger control (whether a lack of control or too much control)
  • Hostility or Type A behavior
  • Psychoticism
  • Cynical distrust
  • Dishonesty
  • Agreeableness
  • Conscientiousness
  • Style of coping behavior
  • Openness to experience
  • Joint effect of personality traits making up a proposed "cancer personality" (variously described, but typically including passive, emotionally inexpressive, conforming and unassertive traits).
Belief in a cancer personality or that personality influences cancer development can serve to stigmatize women with breast cancer and add to their psychological burden. It is notable that the traits posited to be part of a cancer personality generally are regarded negatively or are not regarded as unambiguously positive in our culture. Are happy, well-adjusted women really less likely to get breast cancer?

Latest research finds no link between big five personality traits and cancer

The study referenced at the beginning of this news story was designed to investigate the links between personality traits in the Five Factor Model and risk of cancer and cancer-related mortality. The Five Factor Model assumes that personality can be described in terms of five (the "big five") personality traits, including extraversion, neuroticism, agreeableness, conscientiousness, and openness to experience. To conduct the study, the authors combined and analyzed data from six important prospective studies (British Household Panel Survey; Health and Retirement Study; Household, Income, and Labour Dynamics in Australia; Midlife in the United Survey; Wisconsin Longitudinal Study Graduate; and Sibling samples). The study included 42,843 cancer-free men and women at baseline (55.6% women). A total of 2,156 cancers were diagnosed during an average follow-up period of 5.4 years. Results were adjusted for age, sex, and race/ethnicity.

None of the five personality traits were found to be associated with the overall risk of developing cancer. Nor were they linked to any of the six specific cancers analyzed separately: breast, lung, colon, prostate, skin, and leukemia/lymphoma. In addition, none of the personality traits were associated with cancer mortality in the three studies that included data concerning cancer-specific death. The authors conclude that, based on the study data, personality is not associated with increased risk of cancer or cancer-specific mortality.