sodium-pertechnetate-tc-99m and Rectal-Neoplasms

To assess the performance and the potential clinical impact of a new antibody imaging agent, CEA-Scan (Immunomedics Inc, Morris Plains, NJ), in 210 presurgical patients with advanced recurrent or metastatic colorectal carcinomas.. CEA-Scan, an anti-carcinoembryonic antigen (CEA) Fab antibody fragment labeled with technetium-99m-pertechnetate (99mTc), was injected intravenously (IV), and external scintigraphy was performed 2 to 5 and 18 to 24 hours later. Imaging with conventional diagnostic modalities (CDM) was also performed, and findings were confirmed by surgery and histology.. The sensitivity of CEA-Scan was superior to that of CDM in the extrahepatic abdomen (55% v 32%; P = .007) and pelvis (69% v 48%; P = .005), and CEA-Scan findings complemented those of CDM in the liver. Among 122 patients with known disease, the positive predictive value was significantly higher when both modalities were positive (98%) compared with each alone (68% to 70%), potentially obviating the need for histologic confirmation when both tests are positive. Imaging accuracy also was significantly improved by adding CEA-Scan to CDM. In 88 patients with occult cancer, imaging accuracy was enhanced significantly by CEA-Scan combined with CDM (61% v 33%). Potential clinical benefit from CEA-Scan was demonstrated in 89 of 210 patients. Only two patients developed human antimouse antibodies (HAMA) to CEA-Scan after a single injection, and none of 19 assessable patients after two injections.. CEA-Scan affords high-quality, same-day imaging, uses an inexpensive and readily available radio-nuclide, adds clinically significant information in assessing extent and location of disease in colorectal cancer patients, and only rarely induces a HAMA response.

Topics: Antibodies, Monoclonal; Carcinoembryonic Antigen; Colonic Neoplasms; Humans; Immunoglobulin Fab Fragments; Male; Middle Aged; Predictive Value of Tests; Prospective Studies; Radioimmunodetection; Rectal Neoplasms; Sensitivity and Specificity; Sodium Pertechnetate Tc 99m; United States

In an effort to identify the site of recurrent colorectal cancer in patients with occult metastasis and increasing serum CEA levels, we conducted two trials using monoclonal antibodies (MoAb) against CEA. The first utilized Indium-111-labeled ZCE-025; an immunoglobulin G1 (IgG1) anticarcinoembryonic antigen (anti-CEA) antibody (Hybritech, San Diego, CA). The second study used Tc-99m-labeled Fab' fragment of IMMU-4 (Immunomedics, Morris Plains, NJ). Eighteen patients were imaged with the ZCE-025 and 14 with the Tc-99m Fab' IMMU-4. True-positive scans, defined as at least one correct correlation of the MoAb scan and surgical/histologic findings, were observed in 12 of 15 patients undergoing exploration or biopsy using the ZCE-025 and 11 of 14 using the IMMU-4. There were no true-negative scans with the ZCE-025 and only 2 of 14 with the IMMU-4. There were 3 false-positive scans with the ZCE-025 and 1 of 14 with IMMU-4. There were no false-negative scans with either ZCE-025 or IMMU-4. Four (31%) of 13 patients undergoing exploration and imaged with ZCE-025 and 5 (36%) of 14 imaged with IMMU-4 had complete tumor resection. Treatment decisions were affected in 3 (16%) of 18 ZCE-025-imaged patients and 3 (21%) of 14 IMMU-4 ones. Two (14%) of 14 patients imaged with IMMU-4 had negative MoAb scans and negative laparotomies. Despite these findings, it is not known whether such early detection and resection will translate into improved survival rates. The authors suggest two randomized studies, one designed to ascertain the role of MoAb added to blind exploratory laparotomy. In that study, patients with increasing CEA levels and a negative workup will be randomized to an exploratory laparotomy preceded by MoAb anti-CEA scans or a straight exploratory laparotomy without the assistance of a MoAb anti-CEA scan. Endpoints will be differences in complete resectability and survival. A second study will examine the merits of blind exploratory laparotomies. In that study, patients with increasing CEA levels and a negative workup would be randomized to MoAb imaging, exploratory laparotomy, and radioimmunoguided surgery, and the other cohort of patients would continue to have conventional radiologic workup. Exploration in this latter group would be performed only when indicated by radiologic or endoscopic studies. The endpoint of the study would compare survival in the two cohorts of patients. These two studies may ultimately settle the debate regarding the correct approach t

Topics: Antibodies, Monoclonal; Carcinoembryonic Antigen; Colonic Neoplasms; Humans; Indium Radioisotopes; Laparotomy; Neoplasm Metastasis; Neoplasm Recurrence, Local; Radioimmunodetection; Rectal Neoplasms; Sensitivity and Specificity; Sodium Pertechnetate Tc 99m; Tomography, Emission-Computed, Single-Photon

The anti-carcinoembryonic antigen (CEA) antibody, BW 431/26 (Scintimun CEA, Behringwerke, Marburg, Germany ) labeled with technetium pertechnectate (99mTc), is an intact immunoglobulin G1, monoclonal antibody that has been used to image colorectal cancer. Planar and SPECT images of chest, abdomen and pelvis were performed at 10 minutes, 4-6 and 18-24 hours after the intravenous antibody injection. 44 patients were studied and the pathological antibody concentration localization by radioimmunoimaging (RI) were correlated with surgical, clinical and other imaging modality findings to validate the RI. The RI was positive in 29 patients and negative in the other 15 patients. The CEA and CA 19.9 were elevated in the serum of some patients with primary tumors or recurrence. The HAMA were determined in all the patients before and after the RI.

Topics: Adult; Aged; Animals; Antibodies, Monoclonal; Antigens, Neoplasm; CA-19-9 Antigen; Carcinoembryonic Antigen; Carcinoma; Colonic Neoplasms; Colorectal Neoplasms; Evaluation Studies as Topic; Female; Humans; Male; Mice; Middle Aged; Neoplasm Metastasis; Neoplasm Recurrence, Local; Neoplasm, Residual; Predictive Value of Tests; Radioimmunodetection; Rectal Neoplasms; Sigmoid Neoplasms; Sodium Pertechnetate Tc 99m; Species Specificity; Tomography, Emission-Computed, Single-Photon

Radioimmunodetection of colorectal cancer was evaluated in 51 patients by injecting 131I-labeled goat antibody immunoglobulin G against carcinoembryonic antigen and performing total-body photoscans with a gamma scintillation camera 24 and 48 h later. The scintigrams were then processed by computer to subtract the images of the 99mTc-serum albumin and pertechnetate administered, which reflect background and nontarget radioactivity, from the 131I-antibody scans. The results indicate that radioimmunodetection is a safe and a potentially clinically useful cancer detection method, which in this study demonstrated primary colorectal carcinomas in 10 of 12 (83%) of the patients evaluated preoperatively and between 87% (46 of 53) and 92% (49 of 53) of known metastatic tumor sites. Thus, the method's overall sensitivity (true-positive rate) was 86%-91% on a tumor-site basis. A false-negative rate of between 9% and 14% and a false-positive rate of less than 4% were found. In 11 of the 51 patients evaluated, tumor sites were detected that were not found by other clinical methods of cancer detection. These sites of tumor were then confirmed later, as much as 40 wk after radioimmunodetection was performed. It is concluded that in colorectal cancer patients, the current method of carcinoembryonic antigen radioimmunodetection can (a) contribute to the preoperative clinical staging of the patients, (b) assist in the postoperative evaluation of tumor recurrence or spread, (c) complement other methods used to assess tumor response to therapy, (d) support the indication of a rising carcinoembryonic antigen titer (when other methods cannot detect tumor) for second-look surgery, and (e) confirm the findings of other detection measures that are less tumor-specific.

Topics: Aged; Animals; Carcinoembryonic Antigen; Carcinoma; Colonic Neoplasms; False Negative Reactions; False Positive Reactions; Goats; Humans; Immunoglobulin G; Iodine Radioisotopes; Middle Aged; Radioimmunoassay; Rectal Neoplasms; Serum Albumin; Sodium Pertechnetate Tc 99m; Technetium; Technetium Tc 99m Aggregated Albumin