The prognostic significance of Gail model risk factors for women with breast cancer.

BACKGROUND: Because many risk factors for breast cancer are related to hormonal factors and hormonal factors influence breast cancer prognosis, risk factors may have prognostic value. In order to assess the prognostic value of risk factors for breast cancer we divided patients with breast cancer into those at high risk and low risk using the Gail model.
METHODS: Patients with available follow-up and information concerning age, age at menarche, number of children, age at first birth, number of first degree relatives with breast cancer, and number of previous breast biopsies were divided into low and high-risk groups by the average relative risk calculated using the Gail model. Risk factors, clinical presentations, pathologic findings, tumor characteristics, extent of disease, treatment and outcomes for the 106 high-risk women were compared with the 206 low-risk women. Stage IV patients were excluded.
RESULTS: The average relative risk of breast cancer was 2.09. The 106 high-risk women were significantly older (58 years versus 53 years; P = 0.001), older at first live birth (30 years versus 23 years; P <0.001), more likely to have a first degree relative with breast cancer (57% versus 0%; P <0.001), and more likely to have previously had a breast biopsy (19% versus 1%; P <0.001). There was no difference in the average age at menarche. Low-risk patients were significantly more frequently nulliparous (40% versus 22%; P = 0.002). Clinical presentation, pathologic findings, extent of disease, and treatment were comparable in high and low-risk patients. Cancers of low-risk patients were more frequently poorly differentiated (39% versus 25%, P = 0.044). Tamoxifen was used more frequently in high-risk patients (56% versus 41%; P = 0.012). High-risk patients exhibited significantly better 5-year (95% versus 88%; P = 0.047) and 10-year distant disease-free survival than low-risk patients (88% versus 79%; P = 0.050). In multivariate analysis only the number of involved lymph nodes was related to local (P = 0.001) and distant (P <0.001) disease-free survival.
CONCLUSIONS: Breast cancer patients considered high risk by the Gail model have significantly better disease-free survival than low-risk patients. This study does not support the notion that risk factors for breast cancer are prognostic factors.