The significance of circulating
tumor microemboli (
CTMs) in patients with pancreatic ductal
adenocarcinoma (PDAC) is still unknown. Thus, the present study used a epithelial cellular adhesion molecule independent subtraction and immunostaining-fluorescence in situ hybridization (SET-iFISH) platform to enumerate
circulating tumor cells (CTCs) and
CTMs in a total of 86 peripheral blood samples from 19 patients with PDAC. The associations between CTCs and
CTMs with clinicopathologic factors and prognoses were analyzed. Prior to treatment, CTCs were detected in all 19 patients, and
CTMs were detected in 4 patients with different
tumor-node-
metastasis (TNM) stages. A total of 85 of the 86 peripheral blood samples had
cytokeratin 18-negative CTCs. The number of CTCs and
CTMs were significantly associated with
tumor size and vascular invasion. Patients with
CTMs had poorer overall survival and disease-free survival when compared with those without
CTMs (7.3 vs. 25.40 months, P=0.001; and 1.80 vs. 18.97 months, P=0.037). The presence of
CTMs in the peripheral blood prior to surgery was predictive of poor prognosis in PDAC patients.
CTMs could be detected in patients of different TNM stage (II, III and IV). Surgery did not benefit patients with
CTMs, thus, surgeons should take greater consideration when assessing the requirements for surgery in patients with
CTMs.