Background: Determination of tumor extension and resectability of pancreatic cancer, especially after neoadjuvant chemotherapy, is troublesome on preoperative imaging. The assessment of vascular involvement is particularly important since these are the most affected resection margins, in addition a vascular resection can be performed to aim for a radical resection. The value of intra-operative ultrasound (IOUS) in adequate assessment of tumor extension, vascular involvement and resectability with subsequent IOUS-guided resection has scarcely been studied.

Objective: To assess the added value and diagnostic accuracy of IOUS in predicting resectability of pancreatic cancer.

Study design: Non-randomized prospective multicenter cohort study.

Study population: Patients with (suspected) pancreatic adenocarcinoma planned for curative-intended resection with vascular involvement (excl. splenic vessels) on pre-operative imaging, treated with(out) neoadjuvant chemotherapy, aged 18 years or older.

Primary outcome: Correlation preoperative imaging – IOUS in the assessment of resectability.

Definition of primary outcome:

– Resectable: absence of arterial contactand ≤ 180° venous contact
– Borderline resectable: ≤ 180° arterial contact and reconstructible   venous contact
– Locally Advanced: > 180° arterial contact and unreconstructible venous contact           

Secondary outcomes:

– Change in surgical plan before and after IOUS’
– Correlation between IOUS and pathological examination
– Resection margin status

Sample size: Eighty-five patients are required to achieve 81% power to detect an odds ratio of 7.000 using a two-sided McNemar power test with a significance level of 0.05. The odds ratio is equivalent to a difference between two paired proportions of 0.15. To allow for a valid sub-group analysis, the number of included patients treated with(out) neoadjuvant chemotherapy will be closely monitored.