1654P Circulating tumor cells (CTCs) as prognostic factor for pancreatic cancer: Updated of a prospective study

CTCs have been extensively studied in different neoplasms. There are several techniques for their identification, however, it is not clear which is the most effective. In pancreatic cancer (PC) their significance in different stages of the disease and correlation with tumor markers are poorly understood. Prospective, observational, cohort study in two Spanish centers. We analyzed CTCs at day 0 (before chemotherapy). Isolation was carried out with Isoflux technology, combining cell separation by immunomagnetic particles (positive selection) with a microfluidic system. Four different markers were used, including two mesenchymal markers, EpCAM and EGFR. The count of CTCs was done in a confocal microscope using the iMSRC (intelligent Matrix Screen Remote Control). Primary endpoint was the correlation of CTCs with overall survival (OS). Secondary endpoints: correlation between CTCs with Ca19.9/CEA values and the difference in the median value of CTCs in metastatic compared to locally advanced disease were secondary endpoints. Sixty-three patients were analyzed. Clinical characteristics: (Table) Median follow up was 11.6 months. Median value of CTC-0 was 343 (range 33 - 6259) for metastatic patients while it was 436 (81 - 1082) for locally advanced patients (p = 0.380). Correlation coefficient for Ca 19.9 was 0.03 (p = 0.824); CEA correlation coefficient was 0.121 (p = 0.366). Kaplan-Meier analysis showed an estimated median OS of 9.9 months for > 500 CTCs (95% confident interval [95% CI] 8.1 – 11.6) vs 14.7 (95% confident interval [95% CI] 6.7 – 22.6) for < 500 CTCs (p = 0.021). Table: 1654PClinical characteristicsResultsMedian age (range) - yr65 (45 – 85)Sex – no. (%) Male Female35 (55.67) 28 (44.4)Stage at diagnosis – no. (%) Borderline Locally advanced Metastatic8 (12.7) 16 (25.4) 39 (61.9)BMI – no. (%) Underweight Normal Overweight Obesity2 (3.1) 34 (54) 21 (33.4) 6 (9.5)PS - no. (%) 0 1 212 (19) 43 (68.3) 8 (12.7)CEA – median (range)4.8 (0.5 – 381)Ca 19.9 – median (range)1131 (2 -6627800) Open table in a new tab With an increased number of patients there is still absence of differences of CTC-0 between metastatic and non-metastatic patients as well as no correlation of CTCs with tumor markers at diagnosis. 500 CTCs continues to be a significant cutoff for overall survival.