RADIOIMMUNOSCINTIGRAPHY USING [111IN]ANTIMYOSIN FAB FRAGMENTS FOR THEDIAGNOSIS AND FOLLOW-UP OF RHABDOMYOSARCOMA

Between 1987 and 1992, 39 radioimmunoscintigraphic studies using In-11 1-labelled antimyosin Fab fragments were performed in 27 patients with rhabdomyosarcoma (RMS), 2 patients with leiomyosarcoma (LMS) and 1 wi th alveolar soft tissue sarcoma. 21 patients were children aged 3-14 y ears. These patients, who had histologically proven myosarcoma, were e xamined scintigraphically to search for local recurrences or metastase s and to determine the response to treatment. The results of immunosci ntigraphy were compared with histopathological parameters and other im aging modalities. The sensitivity of antimyosin scintigraphy in this s eries was 82% and the specificity was 73%. Although the technique appe ars to be not highly specific for RMS, it was found to be useful for t he early detection of local recurrence and metastases, as well as for the evaluation of the response to therapy.