Within five years of the diagnosis of operable breast cancer, the disease recurs in up to one third of women. Although factors such as axillary node status and histologic grade are related to recurrence risk, women with apparently similar cancers have dramatically different recurrence and survival experiences. This difference has led to interest in whether personal and environmental factors could influence recurrence. Studies of stressful life experiences have been difficult to conduct and have shown no consistent relationship between adverse life events, such as the death of a spouse or child, and risk of breast-cancer recurrence. Graham and colleagues conducted a prospective study of breast-cancer survivors to objectively establish the impact of stressful life experiences and depression on the risk of breast-cancer recurrence in the five years following initial diagnosis.
They studied women younger than 60 years who were diagnosed with primary operable breast cancer at a London teaching hospital between 1991 and 1994. Patients with a low risk of recurrence because of a very small tumor (less than 1 cm) and no lymph-node involvement were excluded from the study. The women were interviewed every 18 months for the five years following diagnosis. Interviews were conducted and interpreted using standardized techniques that provided a severity rating for stressful life events. The interview incorporated diagnostic criteria for depression. Clinical data and information on recurrence were abstracted from clinical records.
Of the 222 women eligible for the study, 202 (91 percent) completed the initial interview, and 171 (77 percent) provided complete data for five years or until recurrence. The overall five-year disease-free survival rate was 76 percent. Although disease-related factors were worse in the 54 women in whom breast cancer recurred, sociodemographic factors were similar between these women and the women who remained disease-free. After adjustment for lymph-node status and histo-logic type, the researchers found that the risk of recurrence was not related to severely stressful life experiences or depression during the year before diagnosis. In fact, during the follow-up period, women with depression or severely stressful life experiences had a lower risk of recurrence than other women when disease factors were controlled.
The authors conclude that women who have severely stressful life experiences are not at increased risk of diagnosis or recurrence of breast cancer. Although this finding appears counterintuitive, the methodology of the study is sound, and it is likely that the results are valid. The authors stress that these results can be used to encourage and reassure patients that depression and emotional strain are unlikely to precipitate a return of breast cancer.