broadly , the present invention is directed to a method for reliably staging adenocarcinomas typified by colorectal cancer in patients who are undergoing surgery therefor . the method includes the administration of a radiolabeled tumor - associated glycoprotein antibody to the cancer patient prior to surgical accession of the patient . desirably , the present method includes surgical accession with a radiation detection probe for determining tissue exhibiting elevated levels of radiation . the preferred radiolabel is 125 i , which is used to label an antibody specific to a high molecular weight glycoprotein called tag - 72 . the preferred antibody is cc49 , a murine monoclonal antibody of the igg 1 subclass . with radiolabeled monoclonal antibody cc49 , it preferably is administered to the patient approximately 21 days prior to surgery . following surgical excision of all such tissue which is amenable to excision , the probe is again used to identify any remaining neoplastic tissue or tissue deposits , which may or may not be subjected to further excision attempts . after all possible excision of neoplastic tissue has occurred , final counts are taken with the probe to identify residual tissue deposits not excised . the number and location of the remaining tissue deposits form the basis of the biostaging system disclosed herein .