Soy isoflavone supplementation for breast cancer risk reduction: a randomized phase II trial.

Soy isoflavone consumption may protect against breast cancer development. We conducted a phase IIB trial of soy isoflavone supplementation to examine its effect on breast epithelial proliferation and other biomarkers in the healthy high-risk breast. One hundred and twenty-six consented women underwent a random fine-needle aspiration (rFNA); those with 4,000 or more epithelial cells were randomized to a double-blind 6-month intervention of mixed soy isoflavones (PTIG-2535) or placebo, followed by repeat rFNA. Cells were examined for Ki-67 labeling index and atypia. Expression of 28 genes related to proliferation, apoptosis, and estrogenic effect was measured using quantitative reverse transcriptase PCR. Hormone and protein levels were measured in nipple aspirate fluid (NAF). All statistical tests were two-sided. Ninety-eight women were evaluable for Ki-67 labeling index. In 49 treated women, the median Ki-67 labeling index was 1.18 at entry and 1.12 post intervention, whereas in 49 placebo subjects, it was 0.97 and 0.92 (P for between-group change: 0.32). Menopausal stratification yielded similar results between groups, but within premenopausal soy-treated women, Ki-67 labeling index increased from 1.71 to 2.18 (P = 0.04). We saw no treatment effect on cytologic atypia or NAF parameters. There were significant increases in the expression of 14 of 28 genes within the soy, but not the control group, without significant between-group differences. Plasma genistein values showed excellent compliance. A 6-month intervention of mixed soy isoflavones in healthy, high-risk adult Western women did not reduce breast epithelial proliferation, suggesting a lack of efficacy for breast cancer prevention and a possible adverse effect in premenopausal women.

Reproducibility of ductal lavage cytology and cellularity over a six month interval in high risk women.

BACKGROUND: Ductal lavage (DL) allows repeat sampling of breast epithelium for serial observation in a chemoprevention setting; however, the reproducibility of duct cannulation, cell yield and cytology has not been addressed. METHODS: We conducted a Phase 2 trial, wherein high risk women chose tamoxifen treatment or observation following an entry DL procedure. We present data from the non-intervention arm of our study to assess the reproducibility of cannulation, cell yield, and cytologic diagnosis from DL of the same duct at two time-points. Inter-observer variability was assessed by a blinded review of Papanicoloau-stained slides by two cytopathologists. RESULTS: Sixty-five women had a successful lavage of 187 ducts at baseline and chose observation; 63/65 (97%) had a successful lavage 6 months later. Successful recannulation of the same duct was accomplished in 63 women (97%) and162 ducts (87%). Total epithelial cell yields >or=100 were obtained from 57/65 women (88%) and 129/187 ducts (69%) at baseline, and 46/63 women (73%) and 80/162 ducts (49%) at both time-points. Cytologic diagnosis was reproducible in 27/63 (43%) women and 77/162 (48%) ducts. Inter-observer variability for cytologic diagnosis between two observers showed good agreement (kappa = 0.62). CONCLUSIONS: Recannulation and lavage of the same duct after a 6 month interval can be achieved with high frequency; however, reproducibility of cell yield and cytologic findings from the same duct is sub-optimal, leading to significant attrition of evaluable subjects. The utility of DL for the serial monitoring of breast epithelium is therefore limited.