Abstract 724: Clinical impact of modified telomerase-specific adenovirus-based identification of viable-peritoneal tumor cells in peritoneal lavage fluid in patients with potentially resectable pancreatic cancer

Abstract

Abstract Pancreatic cancer (PC) is a highly aggressive disease with dismal prognosis. Although only a surgical resection can offer the chance of a cure, the 5-year survival rate after a potentially curative resection have been reported to be a low as 10-30 %. In PC, the presence of peritoneal carcinomatosis preclude the possibility of surgical cure, irrespective of the resectability of the primary tumor. Peritoneal lavage cytology (CY) is used widely in the diagnosis and staging of gastric and pancreatic cancer. Positive CY findings (CY+) in PC is defined as stage IV disease, however, the true value of CY+ for the patient’s prognosis remains controversial. We rise the question of whether CY+ status has predictive value for survival and early intraperitoneal recurrence. The aim of this study was to evaluate use of a new genetically modified telomerase-specific replication-selective adenovirus, expressing GFP (TelomeScan F35) in rapid detection of viable peritoneal tumor cell (v-PTC) dissemination of PC. This human clinical trial sought to determine if the presence of virally-detected, rare v-PTC predict peritoneal recurrence and patient outcome. This study was approved by the Osaka Police Hospital IRB. Patients with resectable cytologically or histologically proven ductal adenocarcinoma of the pancreas were enrolled. Peritoneal lavage fluid was harvested just after a laparotomy in 27 patients with PC. Half of the fluid was examined by cytology with papanicolau staining and MOC-31 immunostaining and the remaining half was used to detect v-PTC with TelomeScan F35. To distinguish between leucocyte and cells with epithelial origin, cells were stained with anti-CD45 Ab. To further distinguish cells with primary tumor origin, cells were labeled with anti-CEA and anti-CA19-9 Abs. GFP-positive and CD45-negative, and either CEA- or CA19-9-positive cells were counted as v-PTC. Patients were followed after surgery to evaluate its clinical significance. Among 27 patients aged 57-91 years (16 males and 11 females), 3 were cytologically positive (CY+), other 3 were virally positive by TelomeScan F35 (v-PTC+). All 27 patients underwent a surgical resection (PD/DP/TP/H-PD=13/7/6/1). One patient was double positive (CY+/v-PTC+), and postoperative peritoneal recurrence early occurred at 5 month after resection despite adjvant chemotherapy. 2 were CY+, but v-PTC-, and no recurrence in the abdominal cavity were observed (0%). On the other hand, other 2 were CY-, but v-PTC+, and one of these 2 patients occurred local recurrence in the abdominal cavity (50%). Remaining 22 patients (CY-/v-PTC-) were observed with neither local recurrence nor distant metastasis. In conclusion, the TelomeScan F35-based v-PTC detection may be an independent prognostic factor in patients with resectable PC and had close association with local or peritoneal recurrence. Citation Format: Masahiro Tanemura, Kenta Furukawa, Soichiro Mori, Masahisa Otsuka, Youzo Suzuki, Mitsuyoshi Tei, Toru Masuzawa, Kentaro Kishi, Yasuo Urata, Hiroki Akamatsu. Clinical impact of modified telomerase-specific adenovirus-based identification of viable-peritoneal tumor cells in peritoneal lavage fluid in patients with potentially resectable pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 724. doi:10.1158/1538-7445.AM2017-724