Colorectal tumors: scintigraphy with In-111 anti-CEA monoclonal antibody and correlation with surgical, histopathologic, and immunohistochemical findings.

A prospective clinical study of 17 patients with a histologic diagnosis of colorectal carcinoma proved at colonoscopy and surgery was performed with indium-111 anticarcinoembryonic-antigen (CEA) monoclonal antibody (MoAb), ZCE-025. MoAb scanning depicted nine of 16 primary colorectal carcinomas on planar scintigrams (true-positive findings = 56%) and ten of 16 lesions on single-photon emission computed tomography (SPECT) scans (true-positive findings = 62%). Liver metastases were detected in three of three patients, and lymph node metastases were detected in one of four patients. Immunohistochemical examination for CEA in resected colorectal cancer tissues demonstrated a positive correlation between MoAb imaging of primary lesions and cytoplasmic-stromal intracellular CEA distribution. There was no correlation between CEA serum levels and lesion detectability with MoAb scanning.

Clinical experience with intra lymphatic administration of 111In-labelled monoclonal antibody PAY 276 for the detection of pelvic nodal metastases in prostatic carcinoma.

The ability of 111In-PAY 276 (anti prostatic acid phosphatase antibody) in detecting pelvic lymph node metastasis following bipedal intra lymphatic administration was studied in five patients with carcinoma of the prostate. The labeled antibody was injected directly into the lymphatics of each foot. Planar and tomographic images radioactivity content of lymph nodes resected during staging pelvic lymphadenectomy were compared to the histologic and immunoperoxidase findings. Radioactivity in pelvic lymph nodes was prominently seen within 20 min of injection and was present 16 days later. Persistent accumulation of tracer in the lymphatics of the lower extremities was also observed in all patients 16 days post injection. Radioactivity counts in tumor-free lymph nodes were higher than in tumored lymph nodes resected. Our results demonstrate that intra lymphatic administration of 111In-labeled PAY 276 monoclonal antibody has major technical limitations, and that further research directed at the causes of tracer accumulation in the lymphatics and tumor-free lymph nodes is required.

Scintigraphic detection of gastric and pancreatic carcinomas with In-111 ZCE 025 monoclonal antibody.

We have evaluated the role of In-111 anti-CEA (carcinoembryonic antigen) monoclonal antibody ZCE 025 in 8 patients. Three patients had a confirmed diagnosis of gastric carcinoma. Three had a confirmed diagnosis of pancreatic carcinoma. Two patients had elevated serum levels of CEA with no known primary. Each patient received 5.5 mCi In-111 ZCE 025 infused at doses of 10-80 mg. Planar and single photon emission computed tomography (SPECT) imaging at 3 and 7 days after infusion detected 9 of 12 known tumor sites and all 5 of the previously identified sites of metastasis. In-111 ZCE 025 MoAb imaging also found 6 previously unsuspected tumor sites and changed the preoperative evaluation in 50% of the patients studied. It changed the clinical management in 2 patients and established the site of primary involvement in 2 others. There were no clinical or biochemical reactions. In-111 ZCE 025 monoclonal antibody scintigraphy is a useful adjunct in the evaluation of patients with either gastric or pancreatic carcinoma. It may have a beneficial impact on the surgical decision making in these patients.