Effect of pneumoperitoneum on circulating tumor DNA

Abstract

Background: Release and circulation of tumor DNA could be favored by surgery. No data is available for the effect of laparoscopy on this phenomenon.

Material and methods: The aim of this study was to assess the impact of CO2 laparoscopy on circulating tumor DNA. Two xenografts of ovarian cancer were obtained by intraperitoneal inoculation (IP) of IGR-OV1 or NIH:OVCAR-3 cells in nude rats. CO2 laparoscopy (L), gasless laparoscopy (GL), midline laparotomy (ML) or general anesthesia as a control (C) were randomly carried out when the tumor graft was present in the peritoneal cavity. A sterile blood sample was taken in each case as soon as the experiment was completed. DNA was subsequently extracted and amplified (PCR, primers HLA GH 26 and HLA GH 27 specific for human DNA). In each model, we compared the influence of each surgical approach on circulating tumor DNA. Statistics were performed with the Wilcoxon test and Fisher exact test. 1:

Results: Eighteen rats were included in each group. Our protocol could detect an amount of tumor DNA equivalent to 10 cells/ml of blood. This technique was specific. Circulating tumor DNA was frequently observed in the IGR-OV1 model (45 to 50%), without significant difference between groups (p=0.6). In the NIH: OVCAR-3 model, the detection rate ranged from 22% (control group) to 64% (gasless group); but the overall comparison between the four groups was not significant (p = 0.2).

Conclusion: In this experimental trial, CO2 laparoscopy had no deleterious effect on circulating tumor DNA. Biologic characteristics of tumors could also play a role.