Laparoscopic Ultrasound Still Has a Role in the Staging of Pancreatic Cancer: A Systematic Review of the Literature

Jordan Levy¹, Mehdi Tahiri, MD¹, Geva Maimon, PhD¹, Tsafrir Vanounou, MD, MBA², Simon Bergman, MD, MSc¹. ¹Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, ²Hepatobiliary and Pancreatic Surgery, Jewish General Hospital, McGill University, Montreal, Canada

Background: In the last 10 years, the reported incidence of non-curative laparotomies for pancreatic cancer, using standard imaging techniques for preoperative staging, is 20%-50%. The objectives of this study are 1) to determine the diagnostic accuracy of laparoscopic ultrasound (LUS) in assessing resectability of pancreatic tumors; 2) to compare LUS to standard pre-operative imaging; 3) to determine how the accuracy of these modalities has evolved over time.

Methods: A systematic review was carried out with the following search terms: laparoscopic ultrasound, staging, pancreas, tumor and pancreatic cancer. We systematically searched the EMBASE and Medline databases through September 2014. Inclusion criteria were: prospective studies investigating the accuracy of LUS in determining resectability of pancreatic tumors in patients who had undergone standard imaging procedures. Standard imaging consisted of computed tomography complemented in certain studies by endoscopic ultrasound, transabdominal ultrasound, ERCP and MRI. To account for recent technological advances in imaging techniques, a comparison between modalities was carried out for studies published in the last five years.

Results: 99 studies were initially identified and 19 prospective studies (1,573 patients) were included. LUS correctly predicted resectability in 79% (41%-100%) compared to 55% (29%-85%) for standard imaging. Overall, in patients deemed resectable by standard imaging, LUS prevented non-curative laparotomies in 33%. Of those, the most frequent LUS findings precluding resection were liver metastases (16%) and vascular involvement (15%), and a change in diagnosis from malignant to benign (9%). LUS had a morbidity rate of 0.8% with no mortalities. Between 2009-2014 (3 studies), the diagnostic accuracy of LUS and standard imaging was 96% (87-100%) and 68% (33%-88%), respectively. In the only prospective study comparing LUS to multidimensional CT, the accuracy was 100% vs. 78%, respectively.

Conclusion: The addition of LUS to standard pre-operative imaging improves diagnostic accuracy compared to standard imaging alone and may decrease the number of non-therapeutic laparotomies for pancreatic cancer. Even in the most recent studies, there seems to be a benefit to LUS as a staging modality.