Detection of pelvic recurrence of colorectal carcinoma: prospective, blinded comparison of Tc-99m-IMMU-4 monoclonal antibody scanning and CT.
OBJECTIVE
To prospectively compare the accuracy of imaging with technetium-99m-labeled Fab' fragment of the anti-carcinoembryonic antigen antibody (CEA) IMMU-4 with that of computed tomography (CT) for the detection of pelvic recurrence of colorectal carcinoma.


METHODS
In 61 patients, blinded interpretations of both modalities were correlated with surgical-pathologic (n = 23) or clinical and CT follow-up findings (n = 38).


RESULTS
Sensitivity and specificity with antibody scanning alone and combined with CT (79% and 84% vs 83% and 81%, respectively) were not significantly different from those values for CT alone (66% and 97%, respectively). Sensitivity of antibody scanning was greater for recurrences larger than 2 cm (94% vs 55% [P = .02]), serum CEA more than 2.5 ng/mL (91% vs 40% [P = .03]), and combined planar and single photon emission CT antibody scanning compared with planar alone (79% vs 48% [P = .03]), without a significant decrease in specificity.


CONCLUSIONS
Antibody scanning does not improve on findings at CT alone for recurrent colorectal carcinoma but can help differentiate recurrent tumor from fibrosis.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen / Q000097:blood / Q000276:immunology; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000473:pathology; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D005355:Fibrosis; D005500:Follow-Up Studies; D006801:Humans; D007140:Immunoglobulin Fab Fragments; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology; D010386:Pelvic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D011446:Prospective Studies; D016719:Radioimmunodetection; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D013667:Technetium; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen; D007140:Immunoglobulin Fab Fragments; D013667:Technetium; C081678:arcitumomab