In vivo radioimmunodetection of neuroblastoma

Abstract

Ten children—aged 6 months to 13 years—with histologically confirmed undifferentiated neuroblastoma were tested at diagnosis using radiolabelled monoclonal antibody UJ13A. Six of these patients were also investigated after completion of induction chemotherapy. The purified antibody was labelled with 1 mCi ¹¹¹In (12 instances) or 0.5 mCi ¹³¹I (4 instances). Whole body scans using a gamma-camera were obtained between 24 and 72 h after injection. A complete staging including 24 h urinary catecholamines, abdominal ultrasound, CT scan, skeletal survey, bone scan and bone marrow biopsies was performed for each patient during the same time period. Seven children were Evan's stage IV, two stage III and one stage II with lymph-node involvement. At diagnosis, the labelled antibody detected 29 out of 38 known lesions (76%). It also detected 10 lesions not demonstrated by other methods. After completion of induction chemotherapy the labelled antibody detected 6 out of 10 known lesions (60%) and 4 lesions not shown by conventional methods. In 7 instances (3 at diagnosis and 4 after chemotherapy) radioimmunodetection and conventional techniques were in full agreement. The scintigrams obtained with ¹¹¹In radiolabelled UJ13A monoclonal antibody offered better quality images. Absence of ¹¹¹In bladder activity was another advantage over ¹³¹I, especially in the patients with a pelvic mass. However, uptake of ¹¹¹In in the reticulo-endothelial (RE) system appeared to be more important than RE uptake of ¹³¹I.

Key Words:

• Immunolocalisation
• monoclonal antibody
• neuroblastoma