Background: Although early parity protects against breast cancer later in life, it is a risk factor in the years following pregnancy, particularly when child-bearing is delayed. In a separate study, we have reported that these pregnancy-associated breast cancers (PABC) are more likely to be hormone receptor (HR) negative; we have previously found that random fine needle aspiration (rFNA) of the contralateral breast (CB) frequently have atypia in women with HR negative breast cancer. We now report an analysis of the cytological features of contralateral rFNA in relation to recent parity, with the goal of assessing cytological features which may be risk factors for PABC.
Methods: Women with breast cancer undergoing surgery between 2006 and 2008 were enrolled in a prospective study of rFNA of the CB. Cytological analysis was performed on all the samples, using two scoring systems Masood and Zalles (M and Z). Linear regression analyses were performed relating each score to interval from last pregnancy, stratified for parity, and adjusted for age.
Results: Eighty two patients had rFNA and cytologic analysis. The parous group’s (n=52) interval since last pregnancy was inversely correlated with the overall M score (p=0.034); pleomorphism and (p=0.047 and p=0.013 respectively). M score was also related to age at last pregnancy (p=0.026) as were pleomorphism and chromatin pattern (p=0.044 and 0.035 respectively). In the nulliparous group (n=30), there were no significant relationships between any of the cytological parameters or age.
Conclusion: The CB of women with recent parity display specific cytological abnormalities that are related to risk of breast cancer, particularly HR negative breast cancer. This observation affords the opportunity to further evaluate rFNA as a tool for breast cancer risk assessment following pregnancy, and to identify molecular correlates of nuclear cytological abnormalities that may serve as targets for prevention of ER negative breast cancer.