Abstract 3145: Clinical impact of new liquid biopsy using modified telomerase-specific adenovirus-based identification for viable-peritoneal tumor cells in peritoneal lavage fluid in resectable pancreatic cancer

Abstract

Abstract Pancreatic cancer (PC) is one of the leading causes of cancer-related mortality worldwide. Although surgical resection is the only curable option, less than 20% of the patients diagnosed with localized disease are resectable. The prognosis of these patients after complete resection is extremely poor due to local and systemic recurrence. Peritoneal recurrence is a major recurrence pattern after surgery for PC. Peritoneal lavage cytology (CY) is used widely in the diagnosis and staging of gastric and pancreatic cancer to rule out patients with occult peritoneal metastasis. For gastric cancer, positive cytology (CY+), even in the absence of visible peritoneal metastasis, represents stage IV disease. However, the prognostic significance of CY+ in potentially resectable PC is controversial. We rise the question of whether CY+ status in PC has predictive value for survival and early peritoneal recurrence. Therefore, we conducted this study 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 IRB in Osaka Police Hospital and Rinku General Medical Center. Patients with resectable cytologically or histologically proven ductal adenocarcinoma of the pancreas were enrolled. Peritoneal lavage fluid was harvested just after a laparotomy in 53 patients with PC. Half of the fluid was examined by cytology with papanicolau staining and MOC-31 immunostaining and the remaining half was analyzed 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, anti-CA19-9 and EpCAM Abs. GFP-positive and CD45-negative, and either CEA-, CA19-9 or EpCAM-positive cells were counted as v-PTC by automatic detection system using NIS Elements imaging software. Patients were followed after surgery to evaluate its clinical significance. Among 53 patients aged 53-87 years (30 males and 23 females), 6 were cytologically positive (CY+), other 12 were virally positive by TelomeScan F35 (v-PTC+). All 53 patients underwent a surgical resection (PD/DP/TP=32/14/7). 2 patients were double positive (CY+/v-PTC+), and peritoneal recurrence early occurred at 7 month after surgery despite adjuvant chemotherapy. 4 were CY+, but v-PTC-, and no peritoneal recurrence were observed (0%). On the other hand, other 10 were CY-, but v-PTC+, and 4 of these 10 patients occurred peritoneal recurrence (40%). Remaining 37 patients were double negative (CY-/v-PTC-), peritoneal recurrence were observed in only 4 patients. In conclusion, the TelomeScan F35-based v-PTC(+) status was associated with a significantly increased incidence of peritoneal recurrence in patients with resectable PC, resulting in impaired survival. Citation Format: Masahiro Tanemura, Kenta Furukawa, Manabu Mikamori, Tadafumi Asaoka, Yasuo Urata, Kentaro Kishi. Clinical impact of new liquid biopsy using modified telomerase-specific adenovirus-based identification for viable-peritoneal tumor cells in peritoneal lavage fluid in resectable pancreatic cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3145.