Immunoscintigraphy with 131I-labelled H17E2 monoclonal antibody compared with conventional lymphangiography and computed tomography in the detection of metastases in patients with testicular germ cell tumours.

Abstract 131I-labelled H17E2 monoclonal antibody (MAb) was administered to 16 patients with germ cell tumours of the testis (GCT). Eleven patients had non-seminomatous GCT and five seminoma. The MAb was administered into the webs between the second and third toes of both feet in 12 patients and intravenously in four patients at a dose of 1.5-2mCi. 131I-labelled 2-118 MAb (non-specific) was administered subcutaneously into the webs between the second and third toes of both feet in two patients and intravenously in one patient with non-seminomatous GCT. All three patients had only computed tomography (CT) scan. Patients were scanned immediately after until 7 days post-injection. For comparison all patients had CT scan and eight out of 16 patients had conventional lymphangiography (LG). When the radiolabelled MAb was given subcutaneously, the immunoscan (IS) was true positive in 9/12 (75%) patients and true negative in 2/12 (16.5%) and equivocal in 1/12 (8.5%). The LG gave true positive results in 6/8 (75%) patients and true negative results in 2/8 (25%) and the CT scan true positive results in 8/12 (66.6%) patients, true negative results in 2/12 (16.3%) and false negative results in 2/12 (16.3%). There was an excellent correlation of IS images with the LG results (true positivity 100%). When the radiolabelled MAb was given intravenously, both IS and CT scan gave true positive results in four cases. Our findings showed that the true positivity of IS reached 93.8%, whereas that of CT scan 87.5%. In all three patients who had the 131I-labelled 2-118 non-specific MAb, the IS was false negative, whereas the CT scan was true positive. Thus, this procedure may offer information complementary to that provided by existing conventional imaging methods.