Influence of Endoscopic Stent Insertion on Detection of Circulating Tumor Cells from Obstructing Colon Cancer

Objective: Self-expanding metallic stents (SEMS) have been employed as a palliative treatment for patients with obstructive colorectal cancer or as bridge to surgery for potentially resectable colorectal cancer (CRC). However, concerns have been raised about whether shear forces that act on the tumor during expansion of the stent may result in a release of cancer cells into the circulation (i.e., CTCs). This study was conducted to determine whether insertion of colonic stents results in increased levels of CTCs.

Methods: Between October 2013 and November 2013, three patients who underwent colonic stent insertion for obstructing colorectal cancer were studied. To detect viable CTCs of CRC, we employed a TelomeScanF35 detection system, which was constructed with a GFP-expressing attenuated adenovirus, in which the telomerase promoter regulates viral replication. 7.5ml of peripheral blood samples were obtained before and after stent insertion and after operation.

Results: Three patients were inserted SEMS and performed laparoscopic surgery. In one of these 3 patients, CTCs increased after stent insertion and continued in expression after the operation.

Conclusions: This study demonstrated that endoscopic stent insertion results in dissemination of tumor cells into the peripheral circulation. Although oncological consequences were not examined in this small population, viable CTC detected by TelomeScanF35 may represent a suitable prognostic marker to stratify the risk of patients with distant metastasis following stent insertion for obstructing colon cancer.

Keywords: Bridge to surgery, Circulating tumor cells, Obstructing colon cancer, Self-expanding metallic stent, TelomeScan F35.