In patients with potentially resectable tumors based on preoperative imaging, the most effective therapy is resection, with the primary objective of complete removal of all gross disease with clear histologic margins (R0 resection). The importance of an R0 resection is clear from prior work showing that incomplete resections do not improve survival beyond that achievable with biliary drainage alone (4,57). There is now overwhelming evidence to support the argument that partial hepatectomy, combined with excision of the extrahepatic biliary apparatus, is usually required to achieve this goal (Table 3). A review of several series in the literature shows a close correlation between the proportion of patients submitted to concomitant partial hepatectomy and the proportion of R0 resections achieved. En bloc caudate lobectomy is also often necessary, particularly for tumors extending into the left hepatic duct (67). Since the principal biliary drainage of the caudate lobe is via the left hepatic duct, tumors extending into the left hepatic duct almost always involve the caudate duct and usually require caudate resection (68). A dilated caudate duct, suggesting tumor involvement, may occasionally be visualized on preoperative imaging (Fig. 5). In some cases, intraoperative frozen section of the caudate duct margin may

FIGURE 5 Axial CT scan view of a hilar cholangiocar-cinoma (black arrow) arising primarily from the left hepatic duct. A percutaneous biliary drainage catheter can be seen traversing the tumor. A dilated caudate duct is indicated by the white arrowhead. Abbreviation: CT, computed tomography.

help the decision to proceed to caudate resection. Distinguishing resectable from unresectable tumors demands careful consideration of all available data, as discussed above. Even with high quality imaging, however, a significant proportion of patients are found to have unresectable disease only at the time of laparotomy. In a recent report from MSKCC, approximately 50% of patients with potentially resectable tumors had findings that precluded resection at the time of exploration (29). Staging laparoscopy has been used to in an effort to improve resectability rates, and appears to have a role. Two recent studies specifically analyzing patients with biliary cancer have shown that laparoscopy can identify a large proportion of patients with unresectable disease, primarily in the form of radiographically occult metastases (69,70). Weber et al. evaluated 56 patients with potentially resectable hilar cholangiocarcinomas; 33 were ultimately determined to have unresectable disease, of which 14% or 42% were identified at laparoscopy and spared an unnecessary laparotomy. The yield of laparoscopy was noted to be much higher in patients with more locally advanced tumors (T2 or T3 in the proposed staging system), which is consistent with other studies showing a direct correlation between AJCC T stage and the presence of metastases (71,72). Additionally, a number of recent reports have suggested a potential role for 18F-deoxy glucose-positron emission tomography (FDG-PET) scanning as a means of identifying occult metastatic disease, however, most of these studies include small numbers of patients, and further evaluation is needed before PET can be recommended as a routine screening study for this disease (73-75).

Technical aspects of intraoperative tumor assessment, exposure, and resection are outside the scope of this chapter. The reader is referred to specialty texts for a detailed description of surgical techniques (76). The authors' general approach involves the liberal use of staging laparoscopy, followed by a full exploration of the abdomen and pelvis, including intraoperative US. Resection of the tumor involves, at a minimum, removal of the entire extrahepatic biliary apparatus from just above the pancreas distally to beyond the biliary confluence with a complete porta hepatis lymphadenectomy. Also, for the reasons cited above, en bloc partial hepatectomy is required in nearly every case in order to achieve complete tumor clearance. Tumor involvement of the main portal vein proximal to its bifurcation additionally requires a vascular resection and reconstruction if technically feasible.

The extent of lymphadenectomy that should be performed is an area of controversy, with some surgeons arguing for an extended nodal dissection (71,72). These studies have shown measurable five-year actuarial survival, even in the presence of metastatic disease to para-aortic nodal groups. However, an analysis of studies specifically reporting five-year survival in patients with any nodal involvement would suggest that very few patients benefit from such an aggressive approach (Table 4).

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