Starting from the hypothesis that stressful events, badly elaborated by individuals, can bring a decreasing activity of immunitary system and represent a co-factor in development of breast cancer, analyzing which events are more stressful and as a consequence, which are the ones causing a decreasing of immunitary defence. This study considers the breast cancer in large increasing amongst women. 60 women compiled the Events of Life Questionnaire (Qav) and they have been divided into two groups: 30 elements affected by breast cancer (experimental group) and 30 without evident pathologies (control group). Their age was included between the 25 and 75 years old, they came from the same social class, cultural extraction, instruction level. Throughout every single interview, each one lasting about an a hour with hospitalized patients, we potentially find a depressive personality. The statistic analysis gives extremely interesting results regarding negative events of the affective life: underlining a strong dependence among negative events of affective life relating to the development of the breast cancer This interest start from the evident limit in the medical practice, considering organic problems as the only for disease development, excluding emotional and psychological factors which are part of human being's life. Anyway, today is possible to find especially in onchological medicine, the consciousness that the medical or surgical intervention is not the only duty but is also important to underline, in a more complete view, that the patient's care also depends from the ability of questioning about patient's conditions in every day life; as shown in this study which underlines the necessity of psychotherapeutic intervention for patients affected by breast cancer, specially in pre and post operating phases.