Diagnostic Yield of Primary Circulating Tumor Cells in Women Suspected of Breast Cancer: the BEST (Breast Early Screening Test) Study

Purpose: To determine the diagnostic yield of primary circulating tumor cells in women with suspicion ofbreast cancer, detected as a result of an abnormal mammography. Materials and
Methods: Consecutive womenpresenting for breast biopsy as a result of a mammogram BiRADs of 3 or more, had an 8ml blood sampletaken for primary circulating tumor cell (CTC) detection. Mononuclear cells were obtained using differentialgel centrifugation and CTCs identified using standard immunocytochemistry using anti-mammoglobin. A testwas determined to be positive if 1 CTC was detected.
Results: A total of 144 women with a mean age of 54.7 ±15.6 years participated, 78/144 (53.0%) had breast cancer on biopsy, 65/140 (46.3%) benign pathologies and1(0.7%) non-Hogkins lymphoma. Increasing BiRADs scores were associated with increased cancer detection(p=0.004, RR 1.00, 4.24, 8.50). CTC mammoglobin positive had a sensitivity of 81.1% and specificity of 90.9%,with positive and negative predictive values of 90.9% and 81.1% respectively. Mammoglobin positive CTCsdetected 87% of invasive cancers, while poorly differentiated cancers were negative for mammoglobin. Only50% of in situ cancers and none of the intraductal cancers had CTCs detected. Menopausal status did not affectthe diagnostic yield of the CTC test, which was higher in women with BiRADS 4 mammograms. There was asignificant trend (p<0.0001 Chi squared for trends) in CTC detection frequency from intraductal, in situ andinvasive (OR 1.00, 8.00, 472.00).
Conclusions: The use of primary CTC detection in women suspected of breastcancer has potential uses, especially with invasive cancer, but it failed to detect intra-ductal cancer and 50%of in situ cancer. There was no difference in the diagnostic yield between pre and post menopausal women. Toconfirm its use in reducing biopsies in women with BIRADs 4a mammagrams and in the detection of intervalinvasive breast cancer, larger studies are needed.