Detection of peritoneal carcinomatosis by EUS fine-needle aspiration: Impact on staging and resectability (with videos)

Background Peritoneal carcinomatosis (PC) greatly affects cancer staging and resectability. Objective To compare the PC detection rate by using EUS and noninvasive imaging and to determine the impact on staging and resectability. Design Retrospective study. Setting Single tertiary-care referral center. Patients A prospectively maintained EUS database was reviewed to identify patients who underwent EUS-guided FNA (EUS-FNA) of a peritoneal anomaly. Findings were compared with a strict criterion standard that incorporated cytohistologic, radiologic, and clinical data. Intervention EUS-FNA of a peritoneal anomaly. Main Outcome Measurements Safety and diagnostic yield. Results Of 106 patients, a criterion standard was available in 98 (39 female patients; median age, 65 years). The sensitivity, specificity, and accuracy of EUS-FNA versus CT/magnetic resonance imaging (MRI) was 91% versus 28%, 100% versus 85%, and 94% versus 47%, respectively. In newly diagnosed cancer patients, peritoneal FNA upstaged 17 patients (23.6%). Of 32 patients deemed resectable by pre-EUS CT/MRI, 15 (46.9%) were deemed unresectable based solely on peritoneal FNA. The odds of FNA changing the resectability status remained highly significant after adjustment for cancer type, time between CT/MRI and EUS-FNA, and the quality of CT/MRI. The malignant appearance of the peritoneal anomaly but not the presence of ascites on EUS predicted a positive FNA finding (odds ratio 2.56; 95% confidence interval, 1.23-5.4 and odds ratio 0.83; 95% confidence interval, 0.4-1.8, respectively). There were 3 adverse events among 4 patients. Two of the patients developed abdominal pain and one each hypertensive urgency and pancreatitis. Limitations Retrospective design, single-center, bias toward EUS as a diagnostic test. Conclusion Peritoneal EUS-FNA appears to safely detect radiographically occult PC and improve cancer staging and patient care.