RADIOIMMUNOSCINTIGRAPHY IN PATIENTS WITH EARLY-STAGE CUTANEOUS MALIGNANT-MELANOMA

CT and MRI examinations remain relatively insensitive for the detectio n of metastatic melanoma lesions, especially those of regional lymph n odes. Imaging cutaneous malignant melanoma patients with the Fab fragm ent of monoclonal antibody (MAb) NR-ML-05 labeled with Tc-99m has been reported to increase the accuracy of staging. Our purpose in this stu dy was to assess the sensitivity of Tc-99m-labeled NR-ML-05 in detecti ng the spread of melanoma. Methods: Twenty-six adult cutaneous maligna nt melanoma patients were enrolled in this study and were followed for 6 to 60 mo after radioimmunoscintigraphy. At the time of imaging, 20 patients had their primary lesions resected, whereas the remaining 6 p atients had their primary lesions intact. Results: Radioimmunoscintigr aphy correctly detected 8 of 18 suspicious lesions as malignant, as we ll as 4 additional malignant lesions which had not been suspected prev iously. Radioimmunoscintigraphy also correctly identified 8 of the 18 suspicious lesions as benign. Two of the 18 suspicious lesions were fo und to be false negatives. The overall lesion sensitivity of radioimmu noscintigraphy was 86%. Conclusion: Twenty-four of the 26 patients wer e correctly staged by radioimmunoscintigraphy. The accuracy of staging of cutaneous malignant melanoma patients by clinical and or radiologi c examinations (73%) was greatly improved with the use of radioimmunos cintigraphy (93%). These results suggest that radioimmunoscintigraphy may be a clinically useful adjunct to the current armamentarium for gu idance of medical, and particularly surgical, therapy of cutaneous mal ignant melanoma patients.