Onm-4: Reproductive Factors and Breast Cancer Incidence in Premenopousal Patients: A Case-Control Study

Background: Menstrual characteristics may serve as surrogate measures of endogenous estrogen and may be related to breast cancer risk. This case-control study investigated the relationship between menstrual factors and risk of breast cancer incidence in Iranian Center for Breast Cancer (ICBC). Materials and Methods: Forty seven Cases of breast cancer referred to ICBC and 77 controls were studied. Controls were selected through a random sample of non cancer patients of ICBC. The frequency of different menstrual variables such as age at menarche, time to regularity, cycle length, flow length, infertility was compared between two groups. Results: All of the patients were premenopause and their mean age was 37.4 ± 8.05 years. Logistic regression showed that menarche age < 13 years (OR =1.34 (95% CI, 0.59 – 3.07)), flow length >5 days (OR = 1.08 (95%CI, 0.46 – 2.56)), age of first full term pregnancy>30 years (OR = 4.25 (95%CI, 0.4 – 44.9)), cycle length<28 days (OR = 1.56 (95%CI, 0.66 – 1.71)), increased risk of breast cancer. Even though no significant association was noticed. Conclusion: It seems that different reproductive variables may affect on breast cancer incidence. Even though more research with larger sample size are needed to prove this relation, but close observation of patients with menstrual irregularities regarding breast cancer signs can be beneficial.