Circulating tumor cells in locally advanced pancreatic adenocarcinoma: The ancillary study Circe 07 of the LAP 07 trial.

Abstract

4046 Background: Pancreatic carcinoma is one of the leading causes of cancer-related mortality. At time of diagnosis, 30% of patients present with a locally advanced unresectable but non metastatic carcinoma (LAPC). Theoretically, patients with micrometastatic dissemination at diagnosis should benefit from systemic treatments, whereas radiation therapy should be favored in the others. Based on the hypothesis that circulating tumor cells (CTC) count is a surrogate of the cancer metastatic abilities, CTC detection rates and prognostic value were studied in a prospective cohort of LAPC patients. Methods: LAP07 international multicenter randomized study assesses in patients whose LAPC is controlled after 4 months of gemcitabine-based chemotherapy whether to administrate a chemoradiotherapy could increase overall survival versus continuation of chemotherapy alone. A subgroup of patients included in LAP 07 trial were prospectively screened for CTC before the start of the chemotherapy and after two months of treatment, using the CellSearch technique. Clinico-pathological characteristics and survival of patients were obtained prospectively and were correlated with CTC detection. Results: Seventy-nine patients were included in this ancillary study. One or more CTC/7.5ml were detected in 5% of patients before treatment and in 9% of patients after two months of chemotherapy (overall detection rate: 11% of patients). CTC positivity was associated with poor tumor differentiation (p=0.04), and with shorter overall survival in multivariable analysis (RR=2.5, p=0.01), together with anemia (p=0.005). Conclusions: The evaluation of micrometastatic disease using CTC detection appears as a promising tool which could help to personalize treatment modalities in LAPC patients. Clinical trial information: NCT00634725.