Nipple aspirate fluid cytology and the Gail model for breast cancer risk assessment in a screening population.

BACKGROUND: Recent guidelines suggest that chemoprevention with tamoxifen may be appropriate for women who have a 5-year risk of breast cancer greater than 1.66% calculated using the Gail model. OBJECTIVES: To determine whether nipple aspirate fluid (NAF) cytology combined with the Gail model provides breast cancer risk assessment that is superior to either method alone. METHODS: Prospective observational cohort of 6,904 asymptomatic women. Breast cancer cases were identified through follow-up with the women and linkage to cancer registries. We used proportional hazards modeling to recalculate the coefficients for the predictor variables used in the Gail model. NAF cytology was added to create a second model. The two models were compared using the concordance statistic (c-statistic). RESULTS: During 14.6 years of follow-up, 400 women were diagnosed with breast cancer. There were 940 (14%) women with hyperplasia and 109 (1.6%) women with atypical hyperplasia found in NAF. Adding NAF cytology results to the Gail model significantly improved the model fit (P < 0.0001). The c-statistic for the Gail model was 0.62, indicating only modest discriminatory accuracy. Adding NAF cytology to the model increased the c-statistic to 0.64. NAF cytology results had the largest effect on discriminatory accuracy among women in the upper third of Gail model risk. The relative incidence for the highest quintile of risk score compared with the lowest quintile was 7.2 for the Gail model and 8.0 for the model including NAF cytology. CONCLUSION: NAF cytology has the potential to improve prediction models of breast cancer incidence, particularly for high-risk women.

Multiple sampling for increasing the diagnostic sensitivity of nipple aspirate fluid for atypical cytology.

OBJECTIVE: To determine if repeated collection of nipple aspirate fluid (NAF) can improve the diagnostic sensitivity for cytologic atypia, a marker of increased risk of breast cancer. STUDY DESIGN: Two hundred sixty-seven women without known breast disease volunteered for NAF cytology at 5 6-month intervals over 2 years. NAF samples were prepared on Millipore filters (Millipore Filter Corp., Bedford, Massachusetts, U.S.A.) and stained with a modified Papanicolaou method. Fluid availability and cellular abnormalities were evaluated for each collection attempt. Cellular findings were classified as benign, hyperplasia or atypia. RESULTS: NAF was obtained from 178 women (66.6%) at the first visit and from an additional 15, 10, 2 and 4 women at visits 2, 3, 4 and 5, respectively, for a cumulative total of 78.2% by visit 5. The number of women yielding NAF containing hyperplastic or atypical epithelial cells was determined at each visit. Hyperplastic cells were found in 34 (19.1%) at visit 1 and in an additional 20, 10, 5 and 4 women at visits 2, 3, 4 and 5, respectively. Atypical epithelial cells were present in 12 (6.7%) women at the initial visit and in an additional 11, 7, 5 and 1 women at visits 2, 3, 4 and 5, respectively, for a cumulative percent of 18.2 at visit 5. NAF could not be obtained from 58 women at any visit. CONCLUSION: These findings suggest that an optimum collection method for NAF cytology should consist of at least 3 or 4 separate fluid aspiration attempts. Reviewing repeated multiple samples instead of 1 increases the number of women who can be evaluated and the likelihood of detecting cytologic atypia.