PhD defence D. (Delal) Akdeniz

Summary:

Women who have been diagnosed with primary breast cancer are at increased risk of developing a second new primary tumor in the contralateral breast (contralateral breast cancer). This thesis focused on identifying risk factors associated with contralateral breast cancer. We found that several factors have been associated with this risk. Having genetic mutations in the BRCA1, BRCA2 or CHEK2 gene have been associated with the highest risk of contralateral breast cancer. Further, family history of breast cancer, young age at primary breast cancer diagnosis, high BMI, having a lobular (or lobular mixed) primary breast cancer, an Estrogen receptor negative primary breast cancer, radiotherapy for primary breast cancer (especially in BRCA1/2 mutation carriers), alcohol use, and being aged > 25 years when giving birth for the first time have been associated with an increased risk of contralateral breast cancer. Primary breast cancer treatment with chemotherapy or endocrine therapy, as well as having more than 3 full-term pregnancies and a young age at menopause have been associated with a decreased risk of contralateral breast cancer.