The role of social and psychosocial factors in the development and course of cancer.

This paper reviews studies dealing with the influence of social and psychosocial factors on the manifestation and course of cancer with special emphasis on breast cancer. Considerable social gradients are seen in the manifestation of malignant diseases. Most cancers (e.g. cervix, ovarian and lung cancer, malignancies of the upper respiratory and digestive organs) demonstrate a social gradient to the disadvantage of individuals from lower social ranks. In contrast, breast cancer is more prominent in middle and higher social groups. Evidence of the effects of social stress, especially concerning life-changing events, stems from retrospective and so-called limited prospective studies. With some exceptions, all these studies deal with breast cancer. In retrospective studies it was found that cancer patients report significantly more stressful experiences than do controls. In limited prospective studies the results are less straightforward, but suggest that severe loss events may be related to the manifestation of malignancies. Population studies found that patients from a lower social status had poorer chances of survival than did individuals from more privileged groups. This holds for most cancers including breast cancer. The few available studies dealing with stressful experiences and the recurrence of cancers are inconsistent, although sound methods have been applied. Nevertheless, the available evidence is no argument against performing more refined studies concerning the role of social factors in the onset and course of malignant diseases. These should provide an integration of psychological and biological perspectives.