The effect of parity, breastfeeding history, and duration on clinical and pathological characteristics of breast cancer patients.

Background/aim: The study is aimed to determine the relationship between the delivery and breastfeeding history of the patients and the clinicopathological properties of breast cancer. Materials and methods: A questionnaire was utilized for the study, which included the age of diagnosis, the number of children at the time of diagnosis, the age of the children, and the breastfeeding period of each child. Results: The study included 828 patients. The median age at diagnosis was 47 years for parous women and 42 years for nonparous women (p < 0.001). The tumor size of the patients diagnosed within the breastfeeding period was significantly larger compared to the other patients. Estrogen and progesterone receptor positivity were lower in patients diagnosed during breastfeeding. Additionally, the mean number of positive lymph nodes, dissected lymph nodes, and positive lymph node/dissected lymph node ratio in parous and breastfed patients with a nonmetastatic disease were statistically significantly higher in multivariable analysis than those patients who were nulliparous and have not breastfed. Conclusion: Breast cancer is seen at a later age in patients who are parous than those who have never given birth. Patients who are parous and have breastfed tend to present with a higher stage of the disease.