Gail model for determination of the risk factors of breast cancer
Feza Y. Karakayali1, Yahya Ekici1, Şinasi Sevmiş1, Sema Pehlivan1, Zübeyde Arat2, Gökhan Moray1
1Başkent Üniversitesi Tıp Fakültesi, Genel Cerrahi AD, ANKARA
2Başkent Üniversitesi Tıp Fakültesi Halk Sağlığı AD, ANKARA
Purpose: The aim of the presented study was to determine the hormonal and familial risk factors that might play a role in development of breast cancer in Turkish population and to evaluate the reliability of Gail Model in our society.
Materials and Methods: Patients over 35 years old and in whom all breast cancer risk factors are known were selected as the study group, among them; patients who had breast biopsy at least 5 years ago with a diagnosis of non-proliferative lesion was called as Group 1; control patients as Group 2; patients in Group 1 and 2 who were free of breast cancer at the end of the 5 years follow up were called as Group 3; and the patients who had been operated for breast cancer were named as Group 4. Individual risk of breast cancer was calculated for 5 years by Gail Model for the patients in Group 1 and 2, and the patients in whom breast cancer developed during this time period were determined within these groups. Besides, for the determination of the risk factors in development of breast cancer in Turkish Society, all known risk factors of the patients in Group 3 and 4 were evaluated with the multiple regression test.
Results: In Group 1 (n=343), breast cancer developed in the 2.6% of low-risk patients according to Gail Model, while the rate was 12% in high-risk patients (RR=5). In Group 2 (n=601), breast cancer developed in 4.7% of the low-risk patients, and the corresponding rate was 11.7% in high-risk group (RR=2.6). After evaluation of all the risk factors of Group 3 (n=896) and Group 4 (n=630), risk factors which were found to be significant were the first degree family history for breast cancer; second degree family history for breast cancer, nulliparity, nonbreast-feeding and age (p<0.05).
Conclusions: It is found that Gail Model is a reliable model in calculation of individual risk for development of a breast cancer for Turkish Society. It has come to a decision that the main risk factors that determine the risk of a breast cancer development in Turkish Society are familial or genetic factors rather than the hormonal ones, and with the increasing age risk of breast cancer development increases evidently.
Keywords: Breast cancer, Gail Model, risk factors