Feasibility of Transvaginal NOTES for Diagnostic Peritoneal Exploration and Biopsy in Peritoneal Carcinomatosis of Unknown Primary Origin: A Prospective Pilot Study

AbstractBackground: Peritoneal carcinomatosis (PC) of unknown primary origin remains a diagnostic challenge. Surgical exploration and tissue sampling are often necessary for histopathological diagnosis and treatment planning. Vaginal natural orifice transluminal endoscopic surgery (vNOTES) has been proposed as a minimally invasive access route; however, data on its feasibility for diagnostic peritoneal assessment in this context are limited. This study aimed to assess the technical feasibility of vNOTES for peritoneal exploration, diagnostic biopsy acquisition, and intraoperative estimation of the Peritoneal Cancer Index (PCI) in selected patients with suspected PC of unknown primary origin.Methods: This single-center prospective pilot study included 11 female patients with radiologically suspected PC and undetermined primary malignancy. All patients underwent peritoneal exploration and biopsy via vNOTES. Intraoperative findings and PCI estimates were recorded and descriptively compared with preoperative radiological PCI assessments. No formal statistical comparison was intended due to the exploratory nature of the study. Perioperative outcomes and early postoperative complications were documented.Results: Transvaginal access and peritoneal exploration using vNOTES were successfully performed in all patients without conversion to alternative surgical approaches. Adequate tissue samples for histopathological diagnosis were obtained in every case. The mean surgical PCI was 28.9±4.0, reflecting advanced disease in the study population. No intraoperative or major postoperative complications occurred, and all patients were discharged after an uncomplicated early postoperative course. Radiological and surgical PCI assessments showed a high degree of concordance, likely due to the advanced extent of disease.Conclusions: vNOTES appears to be a technically feasible diagnostic approach for peritoneal exploration and biopsy in selected patients with advanced PC of unknown primary origin. Given the small sample size, absence of a comparative control group, and limited follow-up, these findings should be considered preliminary. Further studies are needed to evaluate safety, oncologic implications, and comparative effectiveness relative to standard diagnostic laparoscopy.