Radioimmunodetection of residual, recurrent or metastatic germ cell tumorsusing technetium-99 anti-(alpha-fetoprotein) Fab ' fragment

Purpose: The majority of patients with germ cell tumors are cured by multim odality therapy that consists of cisplatin-based chemotherapy and/or surgic al resection. Serum tumor markers and conventional radiographs are utilized to stratify patients into treatment categories. Efforts tt, individualize chemotherapy or minimize surgical interventions without compromising outcom e are important. Immunomedics (Morris Plains, New Jersey) developed an anti -(alpha-fetoprotein) (anti-AFP) monoclonal antibody IMMU-30 labeled with 15 -20 mCi technetium-99, and the purpose of this study is to determine the se nsitivity and specificity of radioimmunoscintigraphy using Tc-99m anti-AFP antibody for the diagnosis of active germ cell tumors. Methods: A group of patients with germ cell tumors were enrolled in a non-prospective fashion a nd 48 AFP scans using Tc-99 anti-AFP Fab' fragment were obtained. At the ti me of the AFP scan, serum AFP was elevated in 40 measurements with a median level of 21 ng/ml (1.6-66, 210.0 ng/ml). AFP scans were obtained at the in itial staging, during treatment, at relapse or at long-term follow-up and c ompared with conventional radiographs done within 4 weeks of the AFP scans. Results: An overall diagnostic sensitivity of 89% and specificity of 58% w ere obtained. Conclusions: AFP scanning appears useful and to be sufficient ly sensitive to justify prospective studies comparing the procedure with co nventional imaging.