Intra-operative ultrasound for the detection of hepatic metastases from colorectal cancer

Intraoperative Ultrasound as a Screening Modality for the Detection of Liver Metastases during Resection of Primary Colorectal Cancer - A Systematic Review

Colorectal cancer (CRC) is one of the most common cancer diseases worldwide. One in 4 patients with CRC will have a disseminated disease at the time of diagnosis and often in the form of synchronous liver metastases. Studies suggest that up to 30% of patients have non-recognized hepatic metastases during primary surgery for CRC. Intraoperative ultrasonography examination (IOUS) of the liver to detect liver metastases was considered the gold standard during open CRC surgery. Today laparoscopic surgery is the standard procedure, but laparoscopic ultrasound examination (LUS) is not performed routinely. Aim To perform a systematic review of the test performance of IOUS and LUS regarding the detection of synchronous liver metastases in patients undergoing surgery for primary CRC. Method The literature was systematically reviewed using the search engines: PubMed, Cochrane, Embase and Google. 21 studies were included in the review and the key words: intraoperative ultrasound, laparoscopic ultrasound, staging colon and rectum cancer. Results Intraoperative ultrasound showed a higher sensitivity, specificity, positive predictive value and overall accuracy for the detection liver metastases during surgery for primary CRC, compared to preoperative imaging modalities (ultrasound, computed tomography (CT) and contrast-enhanced computed tomography (CE-CT)). LUS showed a higher detection rate for liver metastases compared to CT, CE-CT and magnetic resonance imaging (MRI). Conclusion This systematic review found that both IOUS and LUS had a higher detection rate regarding liver metastases during primary CRC surgery, especially liver metastases<10 mm in diameter, when compared to US, CT, CE-CT and MRI.

Laparoscopic colectomy for colon cancer: comparable to conventional oncologic surgery?

As a result of the obvious benefits of laparoscopic cholecystectomy, minimally invasive techniques have been applied to more complex gastrointestinal procedures, including colorectal resections. The goal in adapting laparoscopic techniques for colorectal surgery is to offer an operation that results in less pain, shorter hospital stay, more rapid return to normal activities, and improved cosmesis compared with conventional operation. The challenge has been to show that this can be done safely and efficiently and that for cancer patients there is no detrimental oncologic effect. The major issues that have been and continue to be addressed are (1) whether an adequate resection can be performed laparoscopically, (2) whether there is a high rate of wound or port site recurrence following these operations, and (3) whether, by using these techniques, we are trading short-term benefits for a poor long-term oncologic outcome. To answer these fundamental questions, several prospective randomized trials have been conducted and several more are under way. The results of these trials indicate that, in terms of cancer outcome, there is no difference in overall survival, disease-free survival, and wound recurrences in patients treated using laparoscopic techniques compared with conventional operation. In addition, there are short-term benefits associated with the use of these techniques. It can now be said that from an oncologic standpoint, in experienced hands, laparoscopic colectomy for curable colon cancer is equivalent to conventional therapy, and it is superior to conventional operation regarding short-term outcomes. Laparoscopic colectomy for colon cancer should be offered to appropriately selected patients.

Intraoperative sonography in patients with colorectal cancer and resectable liver metastases on preoperative FDG-PET-CT

BACKGROUND

Combined fluorine 18-fluorodeoxyglucose-positron emission tomography-CT imaging has been shown to be of good diagnostic value in the preoperative evaluation of patients with colorectal cancer and liver metastases. The adjunctive use of intraoperative sonography (IOUS) may have a limited impact on treatment selection in these patients.

PURPOSE

To compare the diagnostic performance of preoperative positron emission tomography (PET)-CT alone and PET-CT combined with IOUS in the evaluation of patients who are considered for curative resection of hepatic metastases from colorectal carcinoma.

MATERIALS AND METHODS

Patients with colorectal cancer who underwent resection of hepatic metastases and preoperative PET-CT (with or without contrast-enhanced CT) and IOUS were identified. The performance of the imaging techniques was evaluated through review of the radiologic reports, correlation with surgical and histopathologic findings, and clinical follow-up.

RESULTS

Thirty-one patients (mean age, 63.5 years [range, 53-82 years]) were analyzed. Fifteen patients had received preoperative chemotherapy. The mean interval between PET-CT and IOUS was 22.6 days (range, 1-56 days). In 4 cases, neither PET-CT nor IOUS correctly diagnosed the liver metastases. In all 31 patients, the sensitivity of PET-CT alone and PET-CT combined with IOUS was 63% (95% CI 44-80%) and 93% (95% CI 78-98%), respectively; the positive predictive value was 81% and 89%, respectively. In patients without preoperative chemotherapy (n = 16), the sensitivity of PET-CT alone and PET-CT combined with IOUS was 77% (95% CI 49-94%) and 100% (95% CI 79-100%), respectively. In 11 cases (35%), IOUS altered the surgical strategy.

CONCLUSION

In patients with colorectal carcinoma and potentially resectable liver metastases on preoperative PET-CT, IOUS can provide additional information that may alter decision making with regard to surgical technique.

Laparoscopic approach to colonic cancer: critical appraisal of the literature

BACKGROUND/AIMS

As laparoscopic colectomy finds its place in the surgical armamentarium, the literature concerning the safety, efficacy, and oncological rational for treatment of colonic cancer is also enriched. A review and critical appraisal of the literature on this subject was the aim of this paper.

METHODS

A systematic research and a hand search were conducted to gain access to all controlled studies involving laparoscopic colectomy using the Medline, Embase, HealthSTAR, Cumulative Index for Nursing and Allied Health Literature, CancerLit data bases and the Cochrane Central Register of Controlled Trials for the years 1991-2006.

RESULTS

Over 40 controlled randomized trials and ten systematic reviews and/or meta-analyses were found. Several of the completed controlled randomized trials have published either short- or long-term results; only partial and short-term results are available in rectal cancer. The principal conclusions are that the laparoscopic approach affords better short-term outcomes including surgical site morbidity, but with increased operative times and direct costs. Among the proven long-term outcomes, cancer recurrence and survival do not seem to be worse. Whether conversion, a source of increased operative time and costs, is responsible for poorer outcomes or whether specific settings associated with poorer outcomes are among the causes of conversion remains to be shown. However, there are still concerns as regards specific laparoscopic-related complications.

CONCLUSION

There seems to no real safety problems in performing laparoscopic colectomy for cancer; improvement in operative times, conversion rates, and complications should make laparoscopy the best cost-effective approach to colectomy.

Comparison of Multiphase CT, FDG-PET and Intra-Operative Ultrasound in Patients with Colorectal Liver Metastases Selected for Surgery

BACKGROUND

For patients with colorectal liver metastases, resection is the treatment of choice. Careful selection of these patients is crucial in order to reduce the chance of unexpected findings at laparotomy and abandoning further surgical intervention. Here, we evaluate the predictive value of CT and FDG-PET of the liver and extrahepatic findings compared to findings during laparotomy and 6 months follow-up.

METHODS

131 consecutive patients, selected for hepatic surgery for colorectal liver metastases by CT and FDG-PET, were evaluated prospectively. During surgery, the liver was assessed by intra-operative ultrasound, palpation and histology.

RESULTS

In 127 patients (97%), CT was true-positive for liver metastases. In 3 patients, CT was false-positive and in 1 patient false-negative. In 126 patients (96%), FDG-PET was true-positive for liver metastases, in 2 patients FDG-PET was false-negative, in 3 patients true-negative (negative FDG-PET, false-positive CT). At laparotomy a total of 363 liver metastases was identified: 63 lesions <10 mm [10 (16%) detected by both CT and FDG-PET], 172 lesions of 10-20 mm [123 (72%) CT-positive, 129 (75%) by FDG-PET-positive], and 28 lesions >20 mm [124 (97%) CT-positive, 121 (95%) FDG-PET-positive]. CT and FDG-PET missed approximately 30% of the smaller liver lesions, resulting in a significant change in clinical management during surgery in only nine patients.

CONCLUSIONS

CT and FDG-PET have a similar diagnostic yield for the identification of liver metastases; both modalities being adequate on a patient-basis but inadequate to detect the smallest of liver lesions. However, the clinical relevance of the latter is limited.

Follow-up result afters negative findings on unenhanced hepatic MR imaging for hepatic metastasis from rectal cancer

OBJECTIVE

To assess the follow-up results after negative findings on unenhanced hepatic MR imaging in rectal cancer patients who have undergone locally curative surgery.

MATERIALS AND METHODS

From all pertinent imaging reports and medical records, we selected 255 patients who had negative results on unenhanced hepatic MR imaging. When selecting patients who had undergone curative resection, the following patients were excluded from the study: 1) patients in whom extrahepatic metastases were detected on preoperative staging work-ups, 2) patients in whom the surgery was judged to be non-curative due to peritoneal seeding or local aggressiveness. Cases with follow-up periods of less than 18 months were also excluded, as these cases were considered insufficient to confirm the negative outcomes. Thus, a total of 149 patients were ultimately enrolled in our study. The follow-up results of unenhanced MR imagings were assessed according to the assumption that the newly developed hepatic metastases had been false-negative lesions on preoperative MR image.

RESULTS

During a median follow-up period of 29.3 months, 25 hepatic metastases were detected in 13 patients (8.7%), which indicated a negative predictive value of 91.3%.

CONCLUSION

Unenhanced hepatic MR imaging provides a high negative predictive value with regard to the detection of hepatic metastasis in the preoperative evaluation of rectal cancer.

Colorectal liver metastases: CT, MR imaging, and PET for diagnosis--meta-analysis

PURPOSE

To perform a meta-analysis to obtain sensitivity estimates of computed tomography (CT), magnetic resonance (MR) imaging, and fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) for detection of colorectal liver metastases on per-patient and per-lesion bases.

MATERIALS AND METHODS

MEDLINE, EMBASE, Web of Science, and CANCERLIT databases and Cochrane Database of Systematic Reviews were searched for relevant original articles published from January 1990 to December 2003. Criteria for inclusion of articles were as follows: Articles were reported in the English, German, or French language; CT, MR imaging, or FDG PET was performed to identify and characterize colorectal liver metastases; histopathologic analysis (surgery, biopsy, or autopsy), intraoperative observation (manual palpatation, intraoperative ultrasonography [US]), and/or follow-up US was the reference standard; and data were sufficient for calculation of true-positive or false-negative values. A random-effects linear regression model was used to obtain sensitivity estimates in assessment of liver metastases.

RESULTS

Of 165 identified relevant articles, 61 fulfilled all inclusion criteria. Sensitivity estimates on a per-patient basis for nonhelical CT, helical CT, 1.5-T MR imaging, and FDG PET were 60.2%, 64.7%, 75.8%, and 94.6%, respectively; FDG PET was the most accurate modality. On a per-lesion basis, sensitivity estimates for nonhelical CT, helical CT, 1.0-T MR imaging, 1.5-T MR imaging, and FDG PET were 52.3%, 63.8%, 66.1%, 64.4%, and 75.9%, respectively; nonhelical CT had lowest sensitivity. Estimates of gadolinium-enhanced MR imaging and superparamagnetic iron oxide (SPIO)-enhanced MR imaging were significantly better, compared with nonenhanced MR imaging (P = .019 and P < .001, respectively) and with helical CT with 45 g of iodine or less (P = .02 and P < .001, respectively). For lesions of 1 cm or larger, SPIO-enhanced MR imaging was the most accurate modality (P < .001).

CONCLUSION

FDG PET had significantly higher sensitivity on a per-patient basis, compared with that of the other modalities, but not on a per-lesion basis. Sensitivity estimates for MR imaging with contrast agent were significantly superior to those for helical CT with 45 g of iodine or less.

Current status of laparoscopic resection for colorectal cancer

GOALS

To define the current role of laparoscopic resection for colorectal cancer.

BACKGROUND

Perhaps in no other field has so much controversy been generated by laparoscopy as in its application to curative resection of cancer of the colon and rectum. The main controversy centers around the oncologic outcomes of laparoscopic resections. The 3 major issues are: the adequacy of oncologic resection, recurrence rates and patterns, and the long-term survival.

STUDY

A review of published data by search of Medline database with focus on clinical studies.

RESULTS

Laparoscopic colectomy is feasible and safe. Modest benefits in the quality of life are observed. Same oncologic resection can be performed laparoscopically with no adverse influence on the recurrence rates. In particular, wound recurrences are not a specific complication of laparoscopic technique. At least equivalent survival is obtained by laparoscopic colectomy.

CONCLUSIONS

Laparoscopy does not seem to adversely affect chance of cure of colorectal cancer.

Utility of intraoperative liver ultrasound

Intraoperative ultrasound has become an essential tool for the surgeon in the field of hepatobiliary surgery. No preoperative study has been able to duplicate the sensitivity and specificity of IOUS in the identification of occult lesions. With recent improvements in technology, IOUS has now become an indispensable means of defining the extent of disease and respectability, and providing a guide to anatomic and nonanatomic hepatic resections and minimally invasive and percutaneous ablative techniques.

The value of intraoperative ultrasound during hepatic resection compared with improved preoperative magnetic resonance imaging

BACKGROUND

Patients with colorectal metastases confined to the liver may be cured by resection. Combined bimanual palpation and intraoperative ultrasound (IOUS) augment the detection of colorectal hepatic metastases. The importance of IOUS in the surgical management of hepatic tumors has been demonstrated and should arguably be considered the final diagnostic procedure.

OBJECTIVE

To determine the relevance of routine IOUS prior to hepatic resection compared with improved preoperative Magnetic resonance imaging (MRI).

PATIENTS AND METHODS

Eighty patients with metastatic colorectal adenocarcinoma underwent hepatic resection between 1998 and 2001. The IOUS results were compared with preoperative MRI, bimanual palpation, and resection histopathology. The preoperative surgical plan was compared with the surgical procedure performed. Data were retrospectively analyzed.

RESULTS

IOUS provided additional useful information not available preoperatively for 37 (47%) patients, including the identification of subcentimetre metastatic lesions, characterization of the lesion, and the anatomy of the hepatic vasculature. The preoperative surgical plan was changed secondary to the IOUS findings alone in 14/80 (18%) patients. IOUS did not provide any additional useful information for 43 (53%) patients. A correlation was demonstrated between the preoperative diagnosis, intraoperative findings, and resection histopathology.

CONCLUSION

Accurate diagnostic studies facilitate critically decisive actions during planned hepatic resection(s). The current findings suggest that IOUS provide the most useful additional information for hepatic lesions, despite recent improvements in preoperative MRI scanning. Furthermore, routine IOUS should be employed during hepatic resection for colorectal metastases.

Biliary carcinoembryonic antigen in the diagnosis of occult hepatic metastases from colorectal cancer

BACKGROUND AND OBJECTIVES

Twenty five percent of patients who undergo radical surgical treatment for colorectal cancer have occult hepatic metastases that become evident during the follow-up period. We evaluated whether biliary carcinoembryonic antigen (CEA) measurements could be used in these patients to diagnose occult hepatic metastases.

METHODS

Three groups of patients were enrolled in the study. The first group consisted of patients treated for lithiasis of the common bile duct, the second group was affected by colorectal cancer and evident hepatic metastases, and the third group of patients underwent radical surgical treatment for colorectal cancer but had no evident hepatic metastases.

RESULTS

In the first study group, mean biliary CEA level was 0.52 ng/mL (normal value: 0-5 ng/mL) (diagnostic accuracy: 100%), 83.3 ng/mL in the second group (diagnostic accuracy: 91%) and 3.9 ng/mL in the third group. We registered only one false-positive result in the third group, whereas biliary CEA level was above normal values in the three patients in whom hepatic metastases developed (diagnostic accuracy: 89.5%).

CONCLUSIONS

This study suggests that biliary CEA determination could represent an important method to select patients affected by occult hepatic metastases for inclusion in appropriate treatment protocols.

Hepatic metastases in patients with colorectal cancer: relationship between size of metastases, standard of reference, and detection rates

PURPOSE

To determine the relationship between the size of hepatic metastases, the standard of reference, and the reported detection rate in patients with colorectal cancer.

MATERIALS AND METHODS

With use of a MEDLINE search (January 1994 to January 2001), articles were selected that contained original results on detection of hepatic metastases of colorectal cancer, categorized for size in at least two categories, with use of helical computed tomography (CT), helical CT at arterial portography, or magnetic resonance imaging. Results were compared with the size distribution of hepatic metastases in 47 consecutive patients with colorectal carcinoma, which were detected by using a combination of intraoperative ultrasonography (US) and palpation.

RESULTS

Seven studies met all predefined criteria. Four studies involved intraoperative US in all patients and demonstrated a significant negative correlation (-0.988) between detection rate and fraction of small metastases. These studies had a higher fraction and lower detection rate of small metastases and a lower overall detection rate. A majority (58% [145 of 252]) of metastases in the study population were smaller than 20 mm.

CONCLUSION

Few articles adequately describe the standard of reference and size distribution of hepatic lesions. Hepatic metastases of colorectal cancer are frequently smaller than 20 mm. When the standard of reference is suboptimal, many small metastases are excluded from analysis, and detection rates are therefore inflated.

Prospective, blinded comparison of laparoscopic ultrasonography vs. contrast-enhanced computerized tomography for liver assessment in patients undergoing colorectal carcinoma surgery

PURPOSE

To prospectively and blindly compare intraoperative laparoscopic ultrasonography to preoperative contrast-enhanced computerized tomography in detecting liver lesions in colorectal cancer patients. Additionally, we compared conventional (open) intraoperative ultrasonography with bimanual liver palpation to contrast-enhanced computerized tomography in a subset of patients.

METHODS

From December 1995 to March 1998, 77 consecutive patients underwent curative (n = 63) or palliative (n = 14) resections for colorectal cancer. All patients undergoing curative resections were randomized to either laparoscopic (n = 34) or conventional (n = 29) surgery after informed consent. All patients underwent contrast-enhanced computerized tomography, diagnostic laparoscopy, and laparoscopic ultrasonography before resection. In those patients who had conventional procedures, intraoperative ultrasonography with bimanual liver palpation was also done. All laparoscopic ultrasonography and intraoperative ultrasonography evaluations were performed by one of two radiologists who were blinded to the CT results. All hepatic segments were scanned using a standardized method. The yield of each modality was calculated using the number of lesions identified by each imaging modality divided by the total number of lesions identified.

RESULTS

In 43 of the 77 patients, both the laparoscopic ultrasonography and CT scan were negative for any liver lesions. In 34 patients, a total of 130 lesions were detected by laparoscopic ultrasonography, CT, or both. When compared with laparoscopic ultrasonography, intraoperative ultrasonography with bimanual liver palpation identified one additional metastatic lesion and no additional benign lesions. laparoscopic ultrasonography identified two patients with mets who had negative preoperative contrast-enhanced computerized tomography.

CONCLUSIONS

Laparoscopic ultrasonography of the liver at the time of primary resection of colorectal cancer yields more lesions than preoperative contrast-enhanced computerized tomography and should be considered for routine use during laparoscopic oncologic colorectal surgery.

Intraoperative abdominal ultrasonography

BACKGROUND

Ultrasonography during abdominal surgery has been reported since the 1960s, but its use did not become widespread until the recent availability of high-frequency, high-resolution transducers. This review discusses the application of intraoperative ultrasonography to open and laparoscopic abdominal surgery.

METHODS

A literature search (Medline) was undertaken. All papers pertaining to the subject matter that were located were included in the review.

RESULTS

Intraoperative ultrasonography influences surgical strategy in up to 50 per cent of liver resections for malignancy. It is the single most sensitive technique for the detection of occult hepatic metastases at the time of primary colorectal resection. In pancreatic surgery, intraoperative ultrasonography is of value in the localization of islet cell tumours and in the assessment of resectability of adenocarcinoma. The technique may also have a role in staging laparoscopy, and in the operative management of kidney and gastrointestinal diseases.

CONCLUSION

Ultrasonography is an ideal operative tool as it is safe, reproducible and requires no special patient preparation or positioning. It should be regarded as an essential component of major hepatobiliary and pancreatic procedures. The recent availability of flexible laparoscopic probes is likely to lead to a similar impact on minimal access surgery.

Laparoscopic colectomy for cancer: a review

BACKGROUND

The success of laparoscopic cholecystectomy in providing patient benefits in the immediate postoperative period has led to laparoscopic techniques being used for many other intra-abdominal procedures. Colorectal resection for malignancy is one of the more contentious applications of this new technology, because the postoperative benefits are more subtle and the long-term onco logical results are as yet unknown.

METHODS

A review of the English-language literature was undertaken in order to collate and analyse all published series where 20 or more laparoscopic colectomies were performed. and where the indication for resection in the majority of cases was adenocarcinoma of the colon.

RESULTS

Laparoscopic colectomy for cancer can be performed safely by experienced surgeons, although there is a considerable learning curve for the procedure. The expected benefits of minimal access surgery are provided by laparoscopic colectomy, although to a lesser extent than that seen with other procedures. The oncological safety of the procedure is as yet unproven. It is clear that an equivalent resection can be performed, but not whether this translates to an equivalent recurrence and survival rate. Reports of isolated port site recurrences are of concern.

CONCLUSIONS

Early results of laparoscopic colectomy for cancer are encouraging, although the fate of this procedure rests with the analysis of the large multicentre prospective randomized trials currently under way, particularly with regard to the long-term recurrence and survival rates.

Decision-making in rectal cancer surgery: survey of North American colorectal residency programs

PURPOSE

Although rectal cancer is common in the United States, there is significant variation in management and outcome of this disease. The aim of this study is to measure the amount of variability that exists in the way colorectal surgeons investigate and manage patients with rectal cancer.

METHODS

A detailed questionnaire covering preoperative assessment, operative technique, and follow-up of primary rectal cancer was sent to all colorectal surgeons associated with colorectal residency programs throughout North America.

RESULTS

One hundred ten responses were obtained (response rate, 71 percent). Surgeons were in broad agreement (>75 percent agree) on the routine preoperative use of endorectal ultrasound and carcinoembryonic antigen and the postoperative use of endorectal ultrasound. There was also broad agreement about the use of adjuvant therapy and radical resection for a poorly differentiated uT2,N0 cancer, the use of total mesorectal excision for a mid rectal cancer, and for the choice of loop ileostomy if diversion is necessary. Two-thirds of the surgeons used adjuvant therapy and radical resection for a uT3,N0 cancer and preferred a follow-up schedule of three monthly visits for two years with six monthly visits for the next three years. Opinion was divided (<63 percent agreement) on the use of a preoperative liver scan, the approach to a moderately differentiated uT2,N0 cancer, the use of rectal irrigation before resection, the timing of colonoscopy in a patient with stenosing rectal cancer, and the frequency of postoperative colonoscopies.

CONCLUSIONS

There is considerable variation in the management of low rectal cancer advocated by colorectal surgeon educators. For each histologic and pathologic stage, opinion is divided about which operation is best. Careful outcomes analysis is required to clarify the situation.

Management strategies for colorectal liver metastases--Part I

Colorectal cancer is a common malignancy and the incidence of this disease is increasing. Approximately 50% of patients with colorectal cancer die from recurrent disease following an apparently curative resection of the primary tumour and the liver is the most frequent site of relapse. Although only a small proportion of patients will benefit from resection of liver metastases, this form of treatment offers the only possibility of cure. In selected patients, 5-year survival rates of 25-35% may be achieved following liver resection. A poor prognosis after resection of hepatic metastases is likely when there are more than three metastatic deposits, involved resection margins often as a result of ¿wedge' resections, when there is extrahepatic disease, or when there is nodal involvement at the primary tumour site. Regional hepatic artery infusion chemotherapy may provide palliation and possibly even prolongation of survival for some patients with unresectable metastases. Cytoreductive techniques may also provide palliation in selected patients with hepatic metastases unsuitable for resection; cryotherapy is the most promising of these methods.

Intraoperative laparoscopic liver ultrasonography for staging of colorectal cancer. Initial experience

PURPOSE

This study was undertaken to evaluate the feasibility of intraoperative laparoscopic ultrasonography (ILUS) to completely scan all anatomic segments of the liver through a single port site during laparoscopic resection for colorectal cancer.

METHODS

ILUS was performed in patients who were undergoing laparoscopic colorectal cancer surgery using the following approach: 1) presence of a radiologist in the operating room; 2) introduction of the probe through a single cannula site; 3) standardized sequence of four probe positions on liver surface; 4) identification of all major vascular/biliary hepatic structures as a guideline to scan all parenchymal segments of the liver.

RESULTS

Twenty-two patients who were undergoing laparoscopic colorectal cancer surgery were prospectively enrolled. Computed tomography (CT) scan films were available for an immediate comparative analysis in the first 12 cases. Mean duration of the procedure was 10 (range, 5-15) minutes. All major vascular and biliary structures were identified in all patients. Sixteen focal abnormalities were identified by ILUS, and ten focal abnormalities were identified by CT scan in the same seven patients. In one patient, detection of a suspected metastasis not seen by preoperative CT scan led to conversion of the surgical procedure to a laparotomy.

CONCLUSIONS

ILUS is a safe and expeditious technique that permits scanning of all anatomic liver parenchyma segments through a single cannula site. Because intraoperative palpation of the liver is not possible during laparoscopic colorectal cancer surgery, ILUS should probably be a standard component of the curative laparoscopic colorectal cancer operation.