Protective Factors Against Breast Cancer Development: A Retrospective Study on Breastfeeding and Fertility

Objective: Breast cancer (BC) is the most common type of cancer among women. Various risk and protective factors play a role in its development. This study evaluates the association between parity, breastfeeding, and age at BC diagnosis among women with BC. Methods: Between January 2016 and December 2023, data from follow-up records of 1,014 patients diagnosed with BC and admitted to our hospital’s radiation oncology clinic for radiotherapy treatment were analyzed. The collected data were statistically analyzed using Microsoft Access and SPSS 25.0. Results: When patients with BC were grouped into those under and over the age of 55, a significant association was found between parity and later age at BC diagnosis (odds ratio: 2.02, 95% confidence interval: 1.29-3.16; p<0.002). When the number of live births was evaluated, having more than one live birth was associated with a later age at BC diagnosis (p<0.001). Regarding breastfeeding status, the proportion of patients diagnosed with BC under the age of 55 was 70.4% in the non-lactation group, whereas this rate was approximately 55.1% in the lactation group. This finding suggests that lactation may contribute to delaying the age of BC diagnosis (p<0.001). Conclusion: BC is a multifactorial disease with an increasing incidence. Our study demonstrates that parity and breastfeeding are significantly associated with the age at BC diagnosis. These findings should be interpreted as associations within a BC cohort rather than direct estimates of BC risk Future research will help to further explore these interactions in greater detail.