Increased Risk of Breast Cancer in Multiparous and Lactating Women Attending A Breast Care Clinic in Pakistan: A Paradigm Shift?

Aims and Objectives: A changing paradigm shift with multiparity (MP) and breast feeding (BF) has been reported in recent years in breast cancer (BC). Our aim was to observe associations of parity, BF and other risk factors with BC among a local population attending a breast care clinic. Materials and methods: A total of 1,039 women (mean age 39 +/- 15 years) attended for screening or presented with palpable breast lumps at KIRAN, Pakistan. The majority were in middle and low socioeconomic strata. As per American Cancer Society (ACS) guidelines 2003, mammography and ultrasound were performed, along with fine needle aspiration cytology (FNAC) in 195 women with Breast Imaging Reporting and Data Set (BIRADS) IV/V, high risk patients with BIRADS III on mammography and with suspicious ultrasound findings. Results: The study population was stratified into two groups; one with BC on FNAC in 181 women (17% p < 0.001) and other including 858 healthy women after screening for cancer. The BC group had relative predominance of MP (86% p < 0.001), BF (85% p < 0.001), family history FH (8% p=0.106) and post-menopause PM (49% p < 0.001) as compared to the healthy population. Estimated relative risk (RR) of BC in women with MP, BF, F/H and PM was 3.12 (95% CI=2.05-4.73; p < 0.001), 2.47 (95% CI=1.69-3.61; p < 0.001), 1.45 (95% CI=0.93-2.41; p=1.06) and 2.33 (95% CI=1.70-3.02; p < 0.001) respectively. Higher incidence of BC was observed between 30-40 years 23% (p < 0.001) and between 40-50 years 38% (p < 0.001). Conclusion: MP, BF and PM have significant associations with BC in the studied Pakistani women and this possible paradigm shift now needs to be evaluated for confounding factors.