Mehdi Asadi - Surgical Oncology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Soodabeh Shahidsales - Cancer Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Masoumeh Nouri - Surgical Oncology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Mina Khani - Surgical Oncology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran

Introduction and aim: Several factors are associated with breast cancer, including breast-feeding and the duration of breast-fed. In this study association between breastfeeding and breast cancer risk is investigated. Methods: In this case-control study , each group included 191 women , we studied different factors related to breast cancer, including breast-feeding duration, age at first breast feeding, breastfeeding times, age of menarche, age of menopause, the number of live births and dead birth, the number of abortions , occupation, education, family history of cancer and history of drug addiction . Data were collected and analyzed by SPSS version 16. Results:Duration of breastfeeding had a marginal relationship with breast cancer (P-value = 0.048), have a high age at menarche was observed as a Protective factor for breast cancer (P-value = 0.001), mean age of menarche in two groups respectively 12.45 and 12.91. Education was higher in the control group (P-value = 0.001) such that the percentage of people with education higher than primary was 55.5% and 83.5% respectively in the case and control groups. Less parity (P-value = 0.005), high number of abortions (P-value = 0.001), addiction (P-value = 0.015) family history of cancer (P-value = 0.001) were risk factors for breast cancer. Conclusion: Longer breastfeeding is a protective factor in breast cancer. In addition, parity, high age at menarche, higher education, lack of addiction and a family history of cancer are also factors that reduce the risk of breast cancer.