Beschreibung:
<jats:title>Abstract</jats:title>
<jats:p>Background: Although breast cancer in young women (YW, &lt;40 years) only accounts for ∼7% of cases diagnosed annually, tumors in young patients have more aggressive characteristics and higher mortality rates. The cost of breast cancer increases significantly with more aggressive tumors in terms of treatment costs, physical and psychosocial effects on the patient and her family, and lost productivity. Improved understanding of factors associated with etiology of breast cancer in YW is critical to developing more effective prevention strategies and improved treatments, reducing the burden of breast cancer in this population.</jats:p>
<jats:p>Methods: The Clinical Breast Care Project database was queried to identify all YW with invasive breast cancer or benign breast conditions diagnosed after surgical evaluation between 2001 and 2014 that had questionnaire data available from the time of diagnosis. Epidemiological factors including reproductive and health history and lifestyle choices were using Student's t-tests and chi-square analysis with P&lt;0.05 defining significance.</jats:p>
<jats:p>Results: Neither ethnicity nor family history differed significantly between YW with and without breast cancer. Reproductive factors that differed significantly between groups include longer use of oral contraceptives (P&lt;0.001, 93 compared to 66 months), older age at first full-term pregnancy (FFTP, P = 0.002, 24.5 compared to 22.7 years), and longer duration of breastfeeding in parous YW (P = 0.024, 15.1 compared to 10.4 months) in YW with invasive breast cancer compared to those with benign conditions. YW with invasive breast cancer were also significantly more likely to be married (P = 0.043, 78% compared to 68%) and less likely to exercise (P = 0.003, 31% compared to 17%) compared to those with benign breasts.</jats:p>
<jats:p>Conclusions: Of the factors evaluated, including reproductive history, lifestyle choices, and co-morbidities, only five differed significantly between YW with and without invasive breast cancer. Paradoxically, breastfeeding, which has been associated with reduced the risk of breast cancer, was higher in YW who developed invasive breast cancer. In contrast, parity and use of oral contraceptives are associated with transient increases in breast cancer risk. The older age at FFTP of YW with invasive breast cancer combined with the significantly longer exposures to oral contraceptives may create an environment within the breast favorable to tumor initiation and progression.</jats:p>
<jats:p>Citation Format: Allyson L. Toro, Matthew T. Hueman, Craig D. Shriver, Rachel E. Ellsworth. Epidemiological factors associated with breast cancer in young women. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3450.</jats:p>