Pilot study evaluating the intraoperative localization of radiolabeled monoclonal antibody CC83 in patients with metastatic colorectal carcinoma.
BACKGROUND
CC83, a second-generation monoclonal antibody (MAb) against tumor-associated glycoprotein TAG-72 has been shown to have a higher affinity constant than the anti-TAG MAbs CC49 and B72.3. Clinical studies have shown the effectiveness of both CC49 and B72.3 radiolabeled MAbs in localizing colorectal carcinoma with a hand-held gamma-detecting probe during operation. This current study was designed to assess the safety and tumor-binding ability of radiolabeled CC83 MAb in this setting.


METHODS
Seventeen patients with recurrent colorectal cancer underwent intravenous injection with CC83 MAb radiolabeled with iodine 125 (2.0 mCi125I/0.2 mg CC83 MAb). Exploratory laparotomy was carried out 21 to 28 days after injection, consisting of a thorough traditional exploration followed by a survey with a hand-held gamma-detecting probe. All traditionally suspicious and probe-positive tissue was either biopsied or resected and subsequently examined for the presence of carcinoma by using routine histochemical staining techniques.


RESULTS
Thirty-two sites were identified as suspicious for cancer by traditional surgical exploration and 39 through intraoperative survey with a hand-held gamma-detecting probe in the seventeen patients completing the study. Biopsy or resection yielded 27 tumor sites when tissue was evaluated by using routine hematoxylin-eosin staining. All 27 tumor sites were localized by the radiolabeled CC83 MAb, whereas 12 additional sites were RIGS positive but hematoxylin-eosin negative, resulting in a sensitivity and positive predictive value of 100% and 69%, respectively. Traditional methods of exploration detected 23 of 27 tumor sites (85% sensitivity), and nine false-positive sites were recorded (72% positive predictive value). Occult tumor was found by using CC83 MAb in four (15%) of 27 sites, altering the surgical plan in three patients.


CONCLUSIONS
This initial study indicates that CC83 MAb, when used with RIGS, is safe and sensitive in detecting recurrent intraabdominal colorectal cancer.
Burak
W E
WE
Department of Surgery, Ohio State University, Arthur G. James Cancer Hospital and Research Institute, Columbus.
Schneebaum
S
S
Kim
J A
JA
Arnold
M W
MW
Hinkle
G
G
Berens
A
A
Mojzisik
C
C
Martin
E W
EW
D000328:Adult; D000911:Antibodies, Monoclonal; D000915:Antibody Affinity; D000951:Antigens, Neoplasm / Q000276:immunology*; D014408:Biomarkers, Tumor / Q000276:immunology; D001706:Biopsy; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D007457:Iodine Radioisotopes; D009362:Neoplasm Metastasis; D010865:Pilot Projects; D016719:Radioimmunodetection
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D006023:Glycoproteins; D007457:Iodine Radioisotopes; C047052:tumor-associated antigen 72