Intraoperative Ultrasound Staging for Colorectal Liver Metastases in the Era of Liver-Specific Magnetic Resonance Imaging: Is It Still Worthwhile?

Abstract EN

Background.

To assess the efficacy of intraoperative ultrasound (IOUS) compared with liver-specific magnetic resonance imaging (MRI) in patients with colorectal liver metastases (CRLMs).

Methods.

From January 2010 to December 2017, 721 patients underwent MRI as a part of preoperative workup within 1 month before hepatectomy and were considered for the study.

Early intrahepatic recurrence (relapse at cut surface excluded) was assessed 6 months after the resection and was considered as residual disease undetected by IOUS and/or MRI.

IOUS and MRI performance was compared on a patient-by-patient basis.

Long-term results were also studied.

Results.

A total of 2845 CRLMs were detected by MRI, and the median number of CRLMs per patient was 2 (1–31).

Preoperative chemotherapy was administered in 489 patients (67.8%).

In 177 patients, 379 new nodules were intraoperatively found and resected.

Among 379 newly identified nodules, 317 were histologically proven CRLMs (11.1% of entire series).

The median size of new CRLMs was 6 ± 2.5 mm.

Relationships between intrahepatic vessels and tumors differed between IOUS and MRI in 128 patients (17.7%).

The preoperative surgical plan was intraoperatively changed for 171 patients (23.7%).

Overall, early intrahepatic recurrence occurred in 8.7% of cases.

To assess the diagnostic performance, 24 (3.3%) recurrences at the cut surface were excluded; thus, 5.4% of early relapses were considered for analysis.

The sensitivity of IOUS was superior to MRI (94.5% vs 75.1%), while the specificity was similar (95.7% vs 95.9%).

Multivariate analysis at the hepatic dome or subglissonian and mucinous histology revealed predictive factors of metastases missing at MRI.

The 5-year OS (52.1% vs 37.8%, p=0.006) and DF survival (45.1% vs 33%, p=0.002) were significantly worse among patients with new CRLMs than without.

Conclusions.

IOUS improves staging in patients undergoing resection for CRLMs even in the era of liver-specific MRI.

Intraoperative detection of new CRLMs negatively affects oncologic outcomes.