Breast Cancer Survival and Reproductive Factors: A Follow up Study on Parous Women with Breast Cancer in Iran

Introduction & Aim: Female reproductive indicators such as menarche, age at first full term pregnancy and parity are widely recognised to affect the risk of breast cancer. However, the effect of these reproductive factors on survival from breast cancer needs to be investigated. Method: A prospective cohort study was conducted on 846 parous women recruited at the Cancer Research Centre of Shahid Beheshti University of Medical Sciences (CRC of SBMU) between 2005 and 2017. The patients were followed up until March 2017 whilst being treated. Data were extracted from patients’ hospital records including node CI were calculated. Cox Proportional Hazard Model applied to examine potential predictors of survival using STATA14. Results: Mean follow up time of 790 women included in the final analysis was 3.1 years (SD=1.5). One and Five-year survival rates were 0.97(95%CI:0.95-0.98) and 0.91 (95%CI:0.87-0.93) respectively. Adjusted Cox regression indicated women with more than 3 parities had a 2.86 times excess hazard of death than women with 1 parity(HR=3.86,95%CI:1.18-12.59);4.17 times excess hazard of death for women with age at menarche less than (HR=5.17,95% CI:1.61-16.55); and 15.54 times excess risk of death for women with greater than 30 years old at first full term pregnancy (HR=16.54,95%CI:1.57-174.48). Conclusion: Although reproductive factors have been known to be associated with breast cancer risk, our findings revealed that age at menarche less than 13, more than 3 parities, and first pregnancy age greater than 30 years, negatively, associated with survival time of parous women with breast cancer.

Keywords:

Parous , Breast Cancer , Cohort , menarche , age at first pregnancy