Relationship among CEA expression in tumor, CEA serum level and radioimmunoguided surgery in colorectal cancer

Abstract

Objective: To research the relationship among CEA expression in tumor, CEA serum level and Radioimmunoguided Surgery (RIGS) in Colorectal Cancer. Methods: twenty-nine patients with colorectal cancer wer administered radiolabeled McAb CL58 submucosally via endoscope, and all underwent surgical intervention 3 to 14 days later. Intraoperative radioimmunodetection was performed using a portable gamma-detecting probe (GDP). The counts of tumors were obtained, and tumor-to-normal tissue (T/NT) ratio was calculated. The T/NT ratio of 3:1 was taken as the lowest threshold value of positiveness. Anti-CEA immunohistochemical for all the samples were performed. The CEA serum levels of all the patients before operations were also recorded. Results: The sensitivity for RIGS in detecting primary lesions was 93.1% (27/29). 28 patients (96.6%) had CEA expressions to a greater or less extent. 5 patients (17.2%) had elevated CEA serum. There was no correlation between the CEA serum levels and results of RIGS (P>0.5), and no correlation between the CEA serum levels and CEA expression in tumor (P>0.5). The CEA expression in tumor correlated significantly with the RIGS results (P<0.05). Conclusion: This study indicates that immunostaining can be used to select the patients as candidates who will benefit most from RIGS.