摘要：

The purpose of these prospective, pivotal studies was to assess the performance and the potential clinical impact of a new antibody imaging agent, CEA-Scan T M , in 210 presurgical patients with advanced recurrent or metastatic colorectal carcinomas. CEA-Scan T M , an anti-carcinoembryonic antigen (CEA) Fab' antibody fragment labeled with 9 9 m Tc, was injected IV and external scintigraphy performed 2-5 h and 18-24 h later. Imaging with conventional diagnostic modalities (CDM) was also performed, and findings were confirmed by surgery and histology. The sensitivity of CEA-Scan T M was superior to that of CDM in the extrahepatic abdomen (55% vs 32%, p = 0,007) and pelvis (69% vs 48%, p = 0,005), and CEA-Scan T M findings complemented those of CDM in the liver. Among 122 patients with known disease, the positive predictive value was significantly higher when both modalities were positive (98%) as compared to each alone (68%-70%), potentially obviating the need for histological confirmation when both tests are positive. Imaging accuracy also was significantly improved by adding CEA-Scan T M to CDM. In 88 patients with occult cancer, imaging accuracy was enhanced significantly by CEA-Scan T M combined with CDM (61% vs 33%). Potential clinical benefit from CEA-Scan T M was demonstrated in 89 of 210 patients. Only two patients developed human antimouse antibodies (HAMA) to CEA-Scan T M after a single injection, and none of 19 assessable patients after two injections.Le but de ces etudes prospectives etait de connaitre les performances et l'impact clinique potentiel dans le cancer colorectal de l'immunoscintigraphie realisee avec des fragments Fab' marques au 9 9 m Tc d'un anticorps anti-ACE. L'immunoscintigraphie (IS) a ete pratiquee chez 210 patients atteints de cancer colorectal en cours de recidive ou metastase. Les images ont ete realisees entre 2 et 5 heures et 18 et 24 heures apres administration et comparees aux resultats des autres examens d'imagerie (AEI) et aux donnees de la chirurgie et de l'histologie. La sensibilite de l'IS a ete superieure a celle des AEI pour les localisations abdominales et pelviennes sauf au niveau du foie, les donnees de l'IS ont cependant complete celles des AEI pour la recherche des metastases hepatiques. Parmi les 122 patients qui devaient etre operes pour une recidive connue, la VPP et l'exactitude ont ete ameliorees significativement quand l'IS a ete associee aux AEI. Parmi 88 patients avec un cancer occulte, l'exactitude a egalemente te amelioree. Un benefice clinique potentiel a ete demontre chez 89 des 210 patients. Des anticorps antisouris ne sont apparus que chez deux patients apres une seule administration et chez aucun des 19 patients qui ont eu deux IS.

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