Prostate-specific antigen in nipple aspiration fluid: menstrual cycle variability and correlation with serum prostate-specific antigen.

OBJECTIVES

To determine the variability of prostate-specific antigen (PSA) in the breast ductal fluid (nipple aspiration fluid, NAF) during the menstrual cycles of healthy premenopausal women.

METHODS

Fifteen female volunteers underwent weekly nipple aspiration of ductal fluid from both breasts for the duration of two menstrual cycles. A highly sensitive and specific Third Generation PSA Assay (IMMULITE); Diagnostic Products Corporation, DPC) was used to detect NAF and serum PSA. Associations between NAF PSA and paired serum hormone levels of the pituitary-ovarian axis were tested using the Spearman rank correlation and the Wilcoxon signed rank test. Analysis of variance on log transformed NAF PSA was used to determine the intra- and intervolunteer variability.

RESULTS

NAF PSA ranged from <0.003 to 133,330 ng PSA/g total protein (median 2,030 ng/g). No repeatable pattern of change was observed for individual volunteers and no significant association between NAF PSA and any pituitary-ovarian axis serum hormone was detected. There was no correlation between serum and NAF PSA.

CONCLUSIONS

Weekly NAF sampling in healthy premenopausal women to provide adequate volumes for PSA analysis was successfully achieved. Considerable variation was observed for NAF PSA, which may limit the future potential for this tumor marker in NAF. This variability was not associated with hormones of the pituitary-ovarian axis and did not show repeated cyclical variability during the menstrual cycle. Serum PSA does not appear to be an acceptable indicator of NAF PSA levels.