Immunoscintigraphy and intra-operative radioimmunodetection in the treatment of colorectal carcinoma.

Abstract

Intra-operative radioimmunodetection of malignant involved lymph nodes follows the pre-operative immunoscintigraphy in the treatment of patients with colorectal carcinoma. The aims of this clinical study were to determine the sensitivity of the method, to compare the results in study when using Oncoscint and CEA-Scan and to evaluate the importance of the method of surgery and postoperative adjuvant therapy. 121 patients with colorectal tumours (106 primary and 15 recurrent) were operated on using radioimmunoguided surgery (RIGS). The study compared results of pre-operative immunoscintigraphy, intra-operative radioimmunodetection and postoperative histological examination. Histological investigation used classical H&E staining. In histologically negative and RIGS positive cases the immunohistochemical investigation was supplemented. Two radiopharmaceuticals were used Oncoscint CR 103 (MAb B72.3, Satumomab Pendetide), labelled with 111In in 56 patients and CEA-Scan (IMMU 4-Fab' fragments MAb against CEA, Arcitumomab), labelled with 99mTc in 65 patients. The relationship between RIGS positive results and histological examination was statistically assessed after 38 operations and the most acceptable RIGS evaluating index was determined. All subsequent results were evaluated by this index. Immunoscintigraphy of tumour was positive in 112 cases (92.6%). Fifty-five RIGS positive cases of malignant infiltrated lymph nodes were confirmed by 43 histologically positive examinations (78%). In this group 9 cases were discovered only by immunohistochemistry. Sixty-six remaining RIGS negative results were confirmed in 62 (94%) cases by negative histology. Both immunoscintigraphy and RIGS enable one to make a more accurate diagnosis. While treating the primary disease the use of RIGS may help in assessment of necessary extent of operation performance and in staging of the disease by revealing occult lymph nodes involved. Pre-operative immunoscintigraphy seems to be a useful diagnostic method for detection of tumour recurrence. When comparing two radiopharmaceuticals used, CEA-Scan seems to be more suitable for diagnostic studies, but using the Oncoscint for tumour recurrence detection had some specific benefit, too.