Laparoscopic ultrasound for the detection of hepatic metastases during laparoscopic colorectal cancer surgery

Abstract

The search for liver metastases before surgery forms an accepted part of colorectal cancer surgical practice. Intraoperative ultrasound and manual palpation of liver together form the criterion standard as far as screening for metastases is concerned. However, extracorporeal imaging, such as ultrasound and magnetic resonance imaging, are also widely used. The purpose of this study was to demonstrate the efficacy of laparoscopic ultrasound scan in detection of liver metastases during laparoscopic colorectal cancer surgery by comparison with conventional imaging modalities. A prospective, controlled study was undertaken. A total of 76 consecutive patients undergoing laparoscopic colorectal resections for malignancy were recruited. Patients underwent preoperative liver ultrasound scan and intraoperative blinded laparoscopic ultrasound scan examination performed by a single surgeon. Contrast-enhanced magnetic resonance imaging was performed within 30 days of surgery. Conventional ultrasound scan was negative in all cases. Metastases were identified during simple laparoscopic inspection of the liver in one case. Two cases shown by laparoscopic ultrasound scan to have definite metastases were confirmed by magnetic resonance imaging. In seven further instances laparoscopic ultrasound scan identified suspicious liver masses. In three cases these were confirmed to be metastases at magnetic resonance imaging; one was confirmed as a cyst, and the remaining three suspicious lesions were confirmed at serial magnetic resonance imaging scans to be benign and of no significance. Laparoscopic ultrasound scan with a flexible-tipped probe permits satisfactory hepatic examination. It is superior to conventional ultrasound scan and seems to be as effective as magnetic resonance imaging, although the latter modality is still required to delineate identified lesions.