Chang Woon Choi

Evaluation of Bone Metastases by Tc-99m MDP Imaging in Patients With Stomach Cancer

The authors conducted a retrospective review of 234 bone scans of stomach cancer patients who had been diagnosed at the Seoul National University Hospital. In 106 of the 234 cases (45.3%), there were abnormal bone scan results, suggestive of bone metastases. The most common site of bone metastases was the spine, followed by the ribs, pelvis, femur, and skull. These sites were similar to those known for other malignant diseases. The incidence of bone metastases increased according to the duration of disease, especially within 12 months after diagnosis in patients with stage III gastric cancer. The incidence of bone metastases increased as the clinical stage increased. However, the incidence of metastases did not relate to gastric cancer pathologic type. The authors found 6 cases of “superscan” In the 234 bone scans (2.6%). The bone scan findings correlated positively with the level of serum alkaline phosphatase.

Development of bone marrow immunoscintigraphy using a Tc-99m labeled anti-NCA-95 monoclonal antibody

We evaluated the monoclonal antibody CEA-79.4 against carcinoembryonic antigen as an immunoscintigraphic agent for assessing the state of the bone marrow. Western blotting of human granulocyte extracts with the antibody could confirm that the binding was with the epitope of NCA-95. Immunocytochemical staining of bone marrow aspirates revealed specific uptake of this antibody by granulopoietic cells. The affinity constant was 2-9 x 10(9) L/mol. Immunoscintigraphy using 99mTc-labeled CEA-79.4 in a normal volunteer revealed high uptake in the bone marrow as compared to other organs.

Radioimmunoscintigraphy of advanced gastrointestinal carcinomas employing I-131 labeled CEA-79 monoclonal antibody

CEA-79 is a murine IgG2a type monoclonal antibody (MoAb) generated using purified CEA from culture supernatants of a human colon cancer cell line, LS174T. The association constant and immunoreactivity of the I-131 labeled CEA-79 ranged from 2.0 to 3.2 ×109 l/mole, and from 54 to 74 %, respectively. The purpose of this study was to evaluate the feasibility of radioimmunoscintigraphy employing MoAb CEA-79 in patients with advanced gastrointestinal carcinomas. Two mgs of MoAb CEA-79 was labeled with 111 MBq (3 mCi) of I-131, and infused intravenously in 6 stomach cancer and 16 colon cancer patients. Out of 6 patients with stomach cancer, immunoscintigraphy was able to detect the tumors in 4 cases. However, immunoscintigraphy found out tumors in all patients with colon cancer. Moreover, 1 patient with stomach cancer and 2 patients with colon cancer showed increased uptake of MoAb in the tumor lesions despite normal serum levels of CEA. We could conclude that this antibody has a potential as a new imaging agent for the diagnosis of gastrointestinal carcinoma.