Stressful and adverse life experiences in patients with breast symptoms; a prospective case-control study in Kuopio, Finland.

BACKGROUND

Psychosocial stress is widely thought to play a role in the aetiology of cancer in general and breast cancer in particular. Many studies have investigated the association between stressful life events and risk of breast cancer. However, the field of psychosocial cancer research is often problematic and findings have been contradictory, varying from no association to strong association. This inconsistency in results may be explained by the fact that most of the epidemiological data available come from retrospective case-control studies. We have conducted this case-control study with a so called "limited prospective study design"to reduce the potential for recall bias.

MATERIALS AND METHODS

This study is an extension of the Kuopio Breast Cancer Study. Women with breast symptoms were referred by physicians to the Kuopio University Hospital (Finland) and were asked to participate in this study. The women were interviewed and reports on adverse and stressful life events were obtained before any diagnostic procedures were done, so neither the investigator nor the subject knew the final diagnosis of breast symptoms at the time of the interview. The research method used was the semi-structured in-depth interview method. All study subjects were also asked to complete standardised questionnaires (Beck Depression Inventory, Spielberger Trait Inventory).

RESULTS

The clinical examination and biopsy showed breast cancer (BC) in 34 patients, benign breast disease (BBD) in 53 patients, while 28 study subjects showed to be healthy (HSS). The results indicated that BC patients had had significantly (p=0.02) more very severe (Gr IV) and severe (Gr III) stress in the previous 10 years preceding the investigation than the BBD and HSS groups. The BC group also reported significantly more moderate or severe losses than the BBD or the HSS groups (p=0.0009).

CONCLUSION

The results of this study support an overall association between stressful life events and breast cancer risk. The biological explanation of the overall association might be that stress disturbs various areas of the immune systems predisposing to neoplasia.