ORIGINAL ARTICLES   

The Quarterly Journal of Nuclear Medicine 2003 June;47(2):109-15

Copyright © 2009 EDIZIONI MINERVA MEDICA

language: English

Is there a role for 99mTc-anti-CEA monoclonal antibody imaging in the diagnosis of recurrent colorectal carcinoma?

Fuster D. ^{1, 4}, Maurel J. ², Muxí A. ^{1, 4}, Setoain X. ¹, Ayuso C. ³, Martín F. ¹, Ortega M. L. ¹, Fuertes S. ¹, Pons F. ^{1, 4}

¹ Department of Nuclear Medicine, Hospital Clinic, University of Barcelona, Barcelona, Spain 2 Department of Medical Oncology, Hospital Clinic, University of Barcelona, Barcelona, Spain 3 Department of Radiology, Hospital Clinic, University of Barcelona, Barcelona, Spain 4 «August Pi iSunyer» Institute of Biomedical Investigation (IDIBAPS)

Aim. To eval­u­ate the use­ful­ness of immu­nos­cin­tig­ra­phy ­with an ­anti-CEA mono­clo­nal anti­body frag­ment ­labelled ­with 99mTc for ear­ly detec­tion of color­ec­tal recur­rence in ­patients ­with ris­ing ser­um CEA lev­els.
Methods. Fifty-one con­sec­u­tive ­patients (27 wom­en, 24 men) ­with color­ec­tal can­cer (­mean age 68.9±10.2 ­years) and ris­ing CEA lev­els (16.2±18.2 ng/ml) ­were pros­pec­tive­ly stud­ied. Two immu­nos­cin­tig­ra­phy stud­ies ­were per­formed in 8 ­patients (n=59). Immunoscintigraphy was per­formed ­after i.v. injec­tion of 925 MBq of ­anti-CEA mono­clo­nal anti­body. Planar imag­es of the tho­rax, abdo­men and pel­vis, as ­well as ­SPECT of the abdo­men and pel­vis ­were ­obtained at 4 and 24 ­hours ­after injec­tion. In all cas­es an abdom­i­nal CT ­scan was pre­vi­ous­ly per­formed. Findings ­were val­i­dat­ed by his­to­path­o­log­i­cal anal­y­sis (28 cas­es) or by imag­ing and clin­i­cal fol­low-up of at ­least 6 ­months fol­low­ing the immu­nos­cin­tig­ra­phy (31 cas­es).
Results. Forty-one ­patients did not ­show recur­rence dur­ing fol­low-up. We ­found 18 cas­es ­with con­firmed diag­no­sis of extra­he­pat­ic abdom­i­nal or pel­vic dis­eases, 11 cas­es ­with liv­er metas­ta­ses, 9 in the tho­rax and 2 in the ­bone. In ­patients ­with pel­vic and extra­he­pat­ic abdom­i­nal dis­ease, immu­nos­cin­tig­ra­phy was pos­i­tive in 18 cas­es (14 ­true pos­i­tive, 4 ­false pos­i­tive). From the 14 ­true pos­i­tive ­only 7 cas­es had ­been detect­ed by CT. Immunoscintigraphy was neg­a­tive in the remain­ing 41 cas­es (37 ­true neg­a­tive, 4 ­false neg­a­tive). Therefore, the sen­si­tiv­ity and spec­i­fic­ity for immu­nos­cin­tig­ra­phy in extra­he­pat­ic abdom­i­nal and pel­vic dis­ease ­were 78% and 90%, respec­tive­ly. CT ­results ­showed a low­er sen­si­tiv­ity of 61% (p<0.05) and spec­i­fic­ity of 83%. Liver metas­ta­ses ­were detect­ed by CT in 9 cas­es, but ­only 2 of ­these ­were iden­ti­fied ­using immu­nos­cin­tig­ra­phy.
Conclusion. Scintigraphy ­with ­anti-CEA mono­clo­nal anti­body frag­ment ­labelled ­with 99mTc is super­i­or to CT for the detec­tion of pel­vic and extra­he­pat­ic abdom­i­nal recur­rence of color­ec­tal can­cer, ­while CT is ­more sen­si­tive in the detec­tion of liv­er and ­lung metas­ta­ses. Immunoscintigraphy has a lim­it­ed use­ful­ness in the detec­tion of dis­tant metas­ta­ses, but it may be help­ful in the diag­no­sis of sus­pect­ed color­ec­tal recur­rence in ­patients ­with non-con­clu­sive CT find­ings, ­when FDG-PET is not avail­able.