In vivo radioimmunological lymphoscintigraphy in cancer: the implications of positive findings.

Radionuclide-labeled antibodies to tumor-associated antigens were applied to the detection of the lymphatic spread of carcinoma by the technique of lymphoscintigraphy. In women with proven carcinoma of the breast, all of whom had clinical or surgically proven axillary metastases, 100% of metastases were detected by gamma imaging. In three cases of squamous cell carcinoma of vulva, one with bilateral inguinal metastases, one with ipsilateral metastases, and one with no metastases, imaging revealed that I-131 labeled antibodies were sequestered bilaterally in the inguinal lymph nodes of all three patients. Submucosal injections of the uterine cervix with labeled antibodies were performed in patients with carcinoma of the cervix, and again sequestration of radioactivity was detected in pelvic nodes. Subsequent hysterectomy with lymph node dissection revealed high levels of radioactivity in specific lymph nodes but no evidence of metastatic tumor. In view of previous work by Nossal and his group, we speculate that the sequestration of the antibody was based on trapping of the antigen by the lymph nodes, and an antibody-antigen reaction on the surface of cells within the nodes. To prove this hypothesis, appropriate animal experiments were performed. The detection of antigen trapping may have important implications in the diagnosis and therapy of cancer.