Ductal lavage findings in women with known breast cancer undergoing mastectomy

Background: Ductal lavage has the potential to detect cancer by sampling breast epithelium in asymptomatic high-risk women. To assess the utility of ductal lavage as a cancer diagnostic test, we investigated the association between ductal lavage cytologic findings and histologic findings in women with known breast cancer undergoing mastectomy. Methods: Ductal lavage was performed in the operating room before mastectomy on 44 breasts from 32 women with known cancer and on eight breasts from seven women undergoing prophylactic mastectomy, two with occult malignancy. If the ductal lavage sample from one or more ducts contained enough epithelial cells for a cytologic diagnosis, lavaged ducts were injected with a mixture of colored dye, gelatin, and a radiographic contrast compound after mastectomy, and breast tissue was radiographed and sectioned. Histologic findings in ducts with and without dye were recorded. Associations between cytologic results and histologic results were examined by univariate and multivariable analyses. Results: At least one duct was lavaged in 36 breasts (mean = 1.4 ducts per breast); all histologic and cytologic procedures were completed in 28 breasts and in 39 ducts. Markedly atypical or malignant cytology was found in five cancer-containing breasts. In 39 ducts with complete cytologic and histologic data and when marked atypia or malignant cells defined a positive cytologic test, sensitivity was 43% (95% confidence interval [CI] = 23% to 72%), specificity was 96% (95% CI = 86% to 100%), and accuracy was 77% (95% CI = 63 % to 89 %). When mild or marked atypia or malignant cells defined a positive cytologic test, sensitivity was 79% (95% CI = 57% to 96%), specificity was 64% (95% CI 46% to 83%), and accuracy was 69% (95% CI = 55% to 83%). When all 31 cytologically evaluable breasts were analyzed, sensitivity was 17% (95% CI = 7% to 35%), specificity was 100 % (95 % CI = 5 % to 100 %), and accuracy was 19% (95% CI = 9% to 38%). Conclusion: In breasts with cancer, ductal lavage appears to have low sensitivity and high specificity for cancer detection, possibly because cancer-containing ducts fail to yield fluid or have benign or mildly atypical cytology.