Background: Hepatic resection for metastatic colorectal cancer offers a 5-year survival rate of 30%. Selection of patients who are most likely to benefit from excision is challenging. The judgment is made by radiographic techniques preoperatively and by sight and touch and the instinct of the surgeon intraoperatively. Confirmation that all tumor tissue has been excised relies on the appearance and texture of the tissue and is verified by routine histology. The authors' objective was to evaluate (1) the ability of radioimmunoguided surgery (RIGS) to improve the intraoperative detection of metastatic disease, and (2) any change in the operative plan originating from the information gained in patients with colorectal liver metastases. Methods: Charts and tumor registry data for patients who underwent planned liver resection for colorectal cancer using the RIGS method from January 1985 to December 1993 were reviewed. This group of patients was compared to a similar group that underwent traditional liver resection for metastatic colorectal cancer during the same period. Patients who had the RIGS procedure during the earlier part of the period (1985-1990), were injected with tumor-associated glycoprotein (TAG) antibody B72.3; those in the later period (1990-1993) were injected with the second-generation anti-TAG monoclonal antibody CC49. Both monoclonal antibodies were labeled with sodium iodide I 125. Both traditional and RIGS exploration were used to determine the extent of the malignant process and any change in operative plan. Results: Seventy-four cases of planned liver resection were performed with the RIGS method (group I), and 215 cases were performed with the traditional method (group II). Age and sex distribution were similar in both groups, as were morbidity and mortality, with an overall perioperative mortality of 1%. The distribution and number of metastatic lesions to the liver were the same, although group I included more cases with smaller metastatic lesions and more patients with anatomic resections. No extrahepatic tumor was found in 140 patients (65%) in group II, whereas there were only 21 patients (28%) in group I in whom no extrahepatic disease was detected (P < .001). RIGS exploration identified additional tumor in 12 (16%) of 74 cases: in the gastrohepatic ligament lymph nodes (LN) in five patients, in the celiac axis LN in one patient, and in the periaortic LN in six patients. These discoveries changed the operative plan for all of these patients, avoiding excision in the latter six patients and extending the resection in the other six. Conclusions: RIGS surgery provides an immediate and more accurate intraoperative staging system of patients with colorectal liver metastases than does traditional exploration by identifying additional metastatic disease, mainly to the lymph nodes, thus changing the plan of resection in a significant number of patients. More studies are needed to evaluate any significant survival advantage of patients who undergo removal of all RIGS-positive tissue.
