Contrast-enhanced intra-operative ultrasound as a clinical decision making tool during surgery for colorectal liver metastases: The ULIIS study.

Abstract

422 Background: In the era of parenchymal sparing surgery, detecting more colorectal liver metastases (CRLM) is essential to optimize the treatment. We evaluated the added-value of contrast enhanced intraoperative ultrasound (CE-IOUS) with a prospective design. Methods: We used an optimal 2-stage Simon’s design for this two-center study open for patients with operable CRLMs. Primary objective was the justified clinical utility of contrast-enhanced IOUS. Secondary objectives included detection rate of CRLMs, characterization rate of focal liver lesions, specific toxicity and detection of missing CRLMs. Results: Among the 58 eligible patients, 54 were eligible and assessable. Of these 54 patients, 36 were men (66.7%), median age was 63.6 years (range, 37-81), and 43 patients underwent pre-operative chemotherapy. The median number of CRLMs was 2 (range, 1-11). Pre-operative staging was performed using MRI in all 58 eligible patients, CT scan in 41 (70%) and PET-scan in 21 (36%). Compared to pre-operative staging, IOUS allowed identification of 40 new CRLMs in 11 (20.4%) patients. Furthermore, compared to IOUS, CE-IOUS allowed identification of 9 additional CRLMs in 8 (14.8%) patients. The correct detection rate based on pathological exams was 0.94. No additional missing CRLM was diagnosed. The surgical procedure was altered in 5 (9.26%) patients but was justified only in 4 patients (one lesion was ablated without previous biopsy), leading to a clinical utility rate of 7.70% (95 CI, [3.2, 18.6]). There was no specific toxicity reported. Conclusions: Despite the primary endpoint not met for one protocol violation,the Uliis study demonstrates an added-value for CE-IOUS for surgeons treating CRLMs, especially for advanced cases pre-treated by chemotherapy. Clinical trial information: NCT01880554.