Immunoscintigraphy of adenocarcinomas by means of radiolabeled F(ab')2 fragments of an anti-carcinoembryonic antigen monoclonal antibody: a multicenter study.

F(ab')2 fragments of anti-carcinoembryonic antigen (CEA) monoclonal antibody F023C5, determined to be more suitable than intact IgG and Fab fragments for immunoscintigraphy, were labeled with 131I or conjugated to DTPA for instant 111In-labeling, and administered i.v. (2-3 mCi/0.5 mg) to 509 patients in 11 nuclear medicine departments: 284 patients had gastrointestinal adenocarcinomas, 204 had nongastrointestinal adenocarcinomas and 21 were control; serum CEA was elevated in 169 patients, normal in 115, and not determined in 225. The following results were obtained: (a) no adverse reactions; (b) tumor imaging in 324 patients (in particular, in 81.5% CEA-seropositive and in 69.0% CEA-seronegative patients); (c) no significant difference in sensitivity among the results of the 11 departments; (d) no significant difference in overall sensitivity between 131I-and 111In-labeled immunoradiopharmaceuticals; (e) the fraction of documented lesions imaged was 73.3% in CEA-seropositive and 53.7% in CEA-seronegative patients; (f) the detection of liver metastases was hampered, particularly when using the 111In-labeled reagent, by nonspecific radioactivity uptake; (g) the major cause of negative immunoscintigraphy results was a lack of CEA in tumor lesions, as documented by immunohistochemistry; (h) lesion size is also important since the sensitivity was 64% for lesions up to 2 cm in diameter and 84% for larger lesions; (i) many "unexpected" radiolocalizations were recorded. Most were identified as occult tumor lesions. In 35 patients, this finding contributed to the early detection of tumor recurrences.

Imaging with 131I-labeled monoclonal antibodies to a high-molecular-weight melanoma-associated antigen in patients with melanoma: efficacy of whole immunoglobulin and its F(ab')2 fragments.

In vitro experiments selected optimal conditions to radiolabel with 131I the whole immunoglobulin and F(ab')2 fragments of the monoclonal antibody (MoAb) 225.28S to a high-molecular-weight melanoma-associated antigen (HMW-MAA). Injection of the radiolabeled whole immunoglobulin and F(ab')2 fragments of the MoAb 225.28S into eight patients with melanoma resulted in the accumulation of radioactivity in 10 of 18 metastases. This localization is specific because of the close relationship between detection of HMW-MAA in lesions by immunohistochemical techniques and outcome of immunoscintigraphy and because of the different distribution in tumors and adjacent tissues of radiolabeled F(ab')2 fragments of MoAb 225.28S compared with 99mTc-pertechnetate and with radiolabeled F(ab')2 fragments of MoAb 4C4 to hepatitis B surface antigen. F(ab')2 fragments are superior to whole immunoglobulins to perform immunoscintigraphy, since they markedly reduce the background in bone marrow, liver, and spleen. The sensitivity of the procedure allows the detection of lesions with a diameter of at least 1.5 cm and is influenced by the level of the HMW-MAA in lesions and by their anatomical site.

Multicenter study of immunoscintigraphy with radiolabeled monoclonal antibodies in patients with melanoma.

A multicenter study was performed to analyze the efficacy of 99mTc- and 111In-labeled F(ab')2 fragments of monoclonal antibody (MoAb) 225.28S (reactive with a high molecular weight melanoma associated antigen) to radioimage malignant lesions in patients with melanoma. A total of 254 melanoma patients, carrying 412 documented melanoma lesions, were studied in 10 nuclear medicine departments. A total of 377 lesions were visualized in 206 patients; in particular (a) 250 of 412 known lesions were visualized in 159 of 191 patients known to carry melanoma lesions; (b) 95 occult lesions were visualized in 61 patients of the same group; and (c) 32 lesions were visualized in 15 of 63 patients without diagnosed lesions. The melanomic nature of 101 of 127 radioimaged occult lesions was confirmed by clinical criteria and/or by additional laboratory investigations. These results indicate that immunoscintigraphy with radiolabeled F(ab')2 fragments of MoAb 225.28S can provide clinically useful information. Analysis of the variables influencing the outcome of immunoscintigraphy with 99mTc- and 111In-labeled F(ab')2 fragments of MoAb 225.28S confirmed the role of size, anatomic site, and level of high molecular weight melanoma associated antigen in melanoma lesions. Such analysis also showed, for the first time, the influence (a) of the isotope used to radiolabel the antibody fragments and (b) of the clinical stage of the patients. The present study has shown good agreement in the results obtained by the 10 nuclear medicine departments, suggesting that immunoscintigraphy with radiolabeled F(ab')2 fragments of MoAb 225.28S is a reliable procedure.

Radioimmunoscintigraphy of ovarian cancer with the MOv18 monoclonal antibody.

The monoclonal antibody (Mab) 131I-MOv18 was administered to 30 patients with ovarian carcinoma intravenously (n = 20) and intraperitoneally (n = 10). After intraperitoneal administration, higher tumour uptake (mean values 1.3% vs. 0.8%) and a better tumour/background ratio (mean values 2.8 vs. 1.9) than after intravenous injection were obtained. Moreover, after intraperitoneal administration the uptake in non-affected organs, such as liver and spleen, was lower. However, occasionally the favourable results of the intraperitoneal route were cancelled by persistent pelvic non-specific accumulations of 131I-MOv18. The possibility to change the biodistribution pattern in the latter cases with peritoneal washing was evaluated. 3 patients were submitted to this procedure and an improvement in the radiotracer biodistribution was obtained in 1 case. With regard to tumour detection, the average sensitivity (73%) showed a significant difference from the sensitivities for abdominal (61%) and pelvic lesions (90%). No false positive results were noted.

Somatostatin receptor imaging of small cell lung cancer (SCLC) by means of 111In-DTPA octreotide scintigraphy.

Somatostatin receptors have been described on the membrane of neoplastic cells derived from the APUD system and their expression has also been demonstrated on small cell lung cancer (SCLC) in vitro and in vivo. 21 patients with SCLC were studied using 111In-octreotide (111In-OCT) scintigraphy. Scintigraphic examinations were performed following intravenous (i.v.) injection of 111 MBq 111In-OCT with whole-body scintigraphy and planar scintigraphy of the thorax as well as the SPET technique. No short-term side effects were described following 111In-OCT administration. We studied the 111In-OCT biodistribution in 3 patients with serial scintigraphies at 1, 5 and 24 h. We used the 5 h as standard scanning time for the following 18 patients. The scintigraphic results were compared with those of other conventional diagnostic procedures. 111In-OCT detected 86% (48/56) of the lesions already known at the time of scintigraphy. It was positive in all 20 SCLC patients and negative in one lung adenocarcinoma. 111In-OCT showed high sensitivity for mediastinal metastases (94%) and good sensitivity for bone metastases (75%) and abdominal lymph node metastases (71%). 111In-OCT did not detect two liver metastases. 111In-OCT detected five unknown lesions which were confirmed by other diagnostic examinations. 111In-OCT was also effective in cancer patients with low levels of NSE. Our study shows that 111In-OCT scintigraphy is a reliable, non-invasive technique to detect primary SLCL and its locoregional or distant metastases. The clinical utility of receptor status characterisation obtained with 111In-OCT scintigraphy should be evaluated by means of an appropriate prospective study.

Single-dose intraperitoneal radioimmunotherapy with the murine monoclonal antibody I-131 MOv18: clinical results in patients with minimal residual disease of ovarian cancer.

Sixteen of 19 enrolled patients with minimal residual disease of ovarian cancer (macroscopic disease < 5 mm or positive blind biopsies and/or positive peritoneal washing), demonstrated by surgical second-look, underwent intraperitoneal radioimmunotherapy (RIT) with the radiolabelled monoclonal antibody I-131 MOv18 (mean dose 14 mg of MOv18 with 3700 GBq of I-131) 30-40 days after the second-look procedure. Clinical follow-up and/or third-look evaluation performed 90 days after RIT showed complete response (CR) in 5 patients, no change (NC) in 6 patients and progressive disease (PD) in 5 patients. Follow-up study showed long-term maintained CR in 1 patient (34 months) and relapses in the other 4 patients after a mean disease-free period of 10.5 months. 5 NC patients showed clinical or instrumental progression after a mean disease-free period of 13 months. The toxicity of RIT was negligible. Only 1 patient showed mild and transient bone marrow suppression (platelet count nadir 52,000 mm3 after 30 days). HAMA production was demonstrated in 94% (15/16) of patients. In conclusion, RIT appears to be a very promising therapeutic approach to treat minimal residual disease of ovarian cancer.

Double-tracer scintigraphy with 67Ga-citrate and 99mTc-sulfur colloid in the diagnosis of hepatic tumors.

A method of liver scanning based on a subtraction technique with simultaneous use of two tracers, 67Ga-citrate and 99mTc-sulfur colloid, is described. The subtraction technique isolates radiogallium uptake by the space-occupying hepatic lesions by subtracting interference due to tracer uptake by healthy hepatic tissue. In 82 patients, the method yielded a correct result in 94.7% of the positive scans and in 97.7% of the negatives. Two false positives and one false negative occurred. Very poor results were obtained in the same patients using conventional technetium and gallium scans: only 20.7% of these interpretations were correct. The method proved very helpful in differentiating malignant from benign lesions.

Scintigraphic detection of melanoma metastases with a radiolabeled benzamide ([iodine-123]-(S)-IBZM).

UNLABELLED: Iodine-123-(S)-2-hydroxy-3-iodo-6-methoxy-N-[(1-ethyl-2-pyrrolidinyl) methyl] benzamide ([123I]-(S)-IBZM) is a radiolabeled benzamide usually employed to study neuropsychiatric disorders, such as schizophrenia and Parkinson's disease. The ectodermic origin of melanocytes and the presence of melanin in the substantia nigra are the theoretic basis of the experimental use of this class of tracers for melanoma imaging. METHODS: Eleven patients with proven metastatic melanoma entered the study. Whole-body and planar scintigrams were performed 2, 4 and 24 hr after intravenous injection of a mean tracer activity of 205 MBq. The dosimetric evaluation was performed by the Medical Internal Radiation Dose Committee method. RESULTS: The [123I]-(S)-IBZM scans allowed the detection of all six cutaneous lesions, five of six superficial pathologic lymph nodes, four of five pulmonary and one of two hepatic metastases. The maximum tumor-to-background ratio was 2.6 in planar images. The hepatobiliary excretion of the tracer may limit detection of intra-abdominal lesions. Dosimetry is similar to data for nononcologic patients. CONCLUSION: Although it is unclear if the mechanism of radiopharmaceutical uptake in melanoma is due to binding to membrane receptors or due to interactions with intracellular structures, radiolabeled benzamide is a promising tracer to detect melanoma.

Pilot, multicenter and prospective trials with an anti-CEA antibody.

In this paper we summarize the investigations performed by our group utilizing an anti-CEA monoclonal antibody (F023C5) labelled with different radionuclides in humans. Since 1983 radioimmunoscintigraphy (RIS) was performed on 51 patients with 64 localizations of colo-rectal carcinoma (pilot study). A multicenter clinical trial in a large number of patients (509 pts of which 284 with gastrointestinal cancer) was subsequently carried out in collaboration with ten nuclear medicine centres. High sensitivity and specificity values were obtained by these studies and many unsuspected lesions were recorded. In order to better define the clinical role of RIS, a prospective study was performed on 59 patients with suspected local relapses of colo-rectal cancer. A comparative evaluation of RIS, CT scan, US and MRI was done. RIS and MRI had the highest accuracy (86%) followed by CT scan (68%) and US (54%).

The role of serum carcinoembryonic antigen (CEA) in the management of patients with colorectal carcinoma: the experience of the Istituto Tumori of Milan.

CEA determination has attained an important role in the clinical management of patients with tumors of the colorectal tract. In this paper the experience of the Istituto Tumori of Milan is reviewed and the results are discussed. Three hundred and thirty-six patients were followed after curative resection of colorectal carcinoma. The follow-up period was 15 years, from January 1975 to December 1990 (global follow-up 1358 years). In the course of follow-up 136 patients developed recurrent disease. The number of CEA determinations for each patient ranged from 1 to 37 (mean 8, total 3330). CEA levels of presurgical patients were related to the clinical stage. Among patients who developed recurrences 61% showed an increase in CEA serum levels. In 200 patients with a negative follow-up we observed only 15 cases of false-positive results.

Enhancement of in vivo monoclonal antibody targeting with recombinant interferon and cytokines.

Up to now a number of studies have been performed to determine whether the combined use of cytokines and monoclonal antibodies (MAbs) directed against tumor-associated antigens (TAA) can increase the sensitivity of radioimmunoscintigraphy (RIS). It is well known that human natural and recombinant interferons can enhance the cell surface expression of HLA Class I and II antigens as well as some specific tumor antigens, but there is scanty and conflicting information about the expression and shedding of TAA. Some authors reported that alpha-IFN enhances the expression of a melanoma-associated antigen (MAA), recognized by conventional antiserum. Other authors have found no changes in the expression of MAA identified by MAbs. In a pilot study on patients with malignant melanoma Rosenblum demonstrated an increase in tumor uptake of the anti-melanoma MAb 96.5 after IFN administration. In our study we performed immunoscintigraphy with the anti-melanoma MAb 225.28S in the same patient before and after IFN administration in different doses. We point out the difference in biodistribution in different organs and in blood clearance and discuss the possibility to improve the sensitivity of RIS.

Clinical value of radioimmunoscintigraphy in the follow-up of ovarian carcinoma: a prospective study.

Twenty-five patients treated with debulking surgery and chemotherapy for ovarian cancer were prospectively studied to evaluate the efficacy of radioimmunoscintigraphy (RIS) in detecting residual tumor before second-look surgery. RIS was performed with the monoclonal antibody OC125 F(ab')2 labelled with I-131 without knowledge of clinical data and compared with subsequent surgical results. Second look showed tumor persistence in 12 patients, mostly characterized by small lesions. The overall diagnostic sensitivity of RIS was 50% and the specificity was 85%. In particular, RIS showed better sensitivity for pelvic tumor localizations than for abdominal sites (73% vs 33%); this was due to the inability of RIS to detect upper abdominal lesions. Therefore, our conclusion is that, at present, RIS cannot substitute surgical second-look in the management of ovarian cancer, however, considering that also ultrasonography, computer tomography and magnetic resonance are not always able to give definite diagnostic evidence in the follow-up of ovarian carcinoma, RIS could be added to these procedures to balance the limitations of each method. In this regard, the best application of RIS could be in the follow-up of patients with marker elevation without clinical evidence of disease, especially in the case of pelvic fibrosis or adhesions due to previous therapy, where the other non-invasive tools can give doubtful diagnostic results.

Effects of alpha, beta and gamma recombinant interferons on CEA production from HT-29 human colon adenocarcinoma cell line.

The human colon adenocarcinoma derived cell line HT-29 is a good in vitro model for the study of CEA production and release under various experimental conditions. Many studies indicate that CEA secretion is correlated with cell proliferation and seems to depend on the growth conditions and differentiation characteristics induced by the culture medium. The present study demonstrates that recombinant interferons alpha, beta and gamma (rIFN alpha, rIFN beta, rIFN gamma) can modify CEA production and release by HT-29 cell-line. rIFN gamma in particular causes an enhancement of CEA production and release in the culture medium. This dose-depending effect is in some way correlated to cell growth inhibition since the enhancement of CEA expression in the interferon treated cells is evident in the presence of a reduction in cell proliferation. The activity of rIFN alpha and rIFN beta on CEA release is much less remarkable than that demonstrated by rIFN gamma, and is probably only due to the fact that HT-29 colon adenocarcinoma cells respond poorly to the effects of rIFN alpha and rIFN beta at the doses we used. These findings suggest that CEA production, expression and release can be modulated in a variety of ways under the influence of different rIFN treatment and this situation must be taken into account in immunodiagnostic and immunotherapeutic applications of anti-CEA monoclonal antibodies in the cancer patient.

Radioimmunodetection of malignant melanoma with the 225.28S monoclonal antibody to HMW-MAA.

A review of the studies on the use of the antigen-antibody system HMW-MAA 225.28S in melanoma radioimmunodetection is reported. The results obtained in a pilot study (42 patients with 74 lesions), a multicenter trial (254 patients with 553 lesions) and a prospective study still outstanding (29 patients with 38 lesions) allow to consider this system as suitable for clinical application. F(ab')2 labelled with 99mTc gave the best results in terms of positivity. Moreover this radioisotope allows the best dosimetric conditions. The gamma energy emitted by this radionuclide is particularly convenient for conventional scintillation cameras and ECT. Very good results in terms of sensitivity (70%-85%) and especially specificity (about 100%) were achieved. Possible clinical applications of the method are discussed.

Studies of terminal deoxynucleotidyl transferase in normal and neoplastic human cells.

Optimized biochemical assays and cytoimmunofluorescence tests were used to detect terminal deoxynucleotidyl transferase, TdT, in malignant cells of 36 leukemias and 75 lymphomas from patients not receiving chemotherapy. TdT was virtually absent from normal lymph nodes and from leukocytes of chronic lymphocytic leukemia, CLL, taken as controls. Its quantitative distribution in the neoplasms matched the current knowledge. Appreciable amounts of TdT were found in all the 10 lymphomas of lymphoblastic type, LL, and in the white blood cells of: 16 out of 19 acute lymphoblastic leukemia, AAL, perhaps with modulation in the various phenotypes; 2 out of 3 acute undifferentiated leukemias, AUL; and 3 out of 7 blastic crises in chronic myelogenous leukemia, b.c. CML. Biochemical and cytoimmunological analyses yielded concordant responses and even roughly comparable estimates in the same patients. TdT immunofluorescence was clearly nuclear in most cells and was cytoplasmic occasionally. Definite correlations between concentrations of enzymatic activity and percentage of immunofluorescent cells could not e established. Further detailed work will be required to identify putative subgroups in TdT-positive blast populations.

[Clinical examination and 131 Cs scanning in the diagnosis of cold nodules of the thyroid (author's transl)]. / L'esame clinico e lo studio con radiocesio (131 Cs) nella diagnosi di natura dei noduli freddi tiroidei

The usefulness of 131Cs scanning in preoperative diagnosis of 131I cold nodules of the thyroid that present no clear clinical sign of malignancy is discussed. The results of clinical examination of 283 thyroid nodules, associated in 139 cases with 131Cs scanning, are correlated with the histologic nature. In nodules that were classifided as cold, warm or hot in the 131Cs scan, the incidence of malignancy was 2.6, 12.3 and 25%, respectively. In the nodules that, on the basis of clinical examination, were classified as probably benign, dubious or suspected for malignancy, the incidence of cancer was, respectively, 3.6, 26.3 and 72.7%. Malignancy ocurred in 16 of 144 patients that were selected for surgical treatment only on the basis of clinical data and in 17 of 139 patients that were selected on the basis of clinical examination associated with 131Cs scanning. The accuracy of clinical preoperative diagnosis of thyroid cold nodules does not seem to be significantly improved by association of 131Cs scanning.

Adriamycin and epirubicin treatment monitored by radionuclide ejection fraction during therapy and follow-up.

Twenty-four patients with advanced breast cancer were studied with serial determinations of the radionuclide ejection fraction at rest (RST-LVEF) during anthracycline chemotherapy (CT) and with a mean follow-up (FU) of 8 months. We had 2 cases of anthracycline congestive heart failure (CHF) during FU, 3 and 12 months respectively after the end of CT. The RST-LVEF changes observed during CT were not able to predict which patients were to develop a symptomatic cardiomyopathy. The type of RST-LVEF change that is generally considered a worsening of cardiac performance is a decline greater than or equal to 15%. We had this type of RST-LVEF change, in addition to the 2 CHF, in 5 other patients without symptomatic cardiomyopathy. Nevertheless none of these 5 patients attained pathological values of RST-LVEF, while the 2 CHF showed symptomatic cardiomyopathy only when RST-LVEF became clearly pathologic (less than or equal to 46%). Therefore, although in our study the RST-LVEF changes during CT did not have predictive value for CHF, the method may give a notable clinical contribution all the same. In fact, by submitting the patients with a RST-LVEF fall greater than or equal to 15% to frequent sequential RST-LVEF determinations and stopping the CT if the RST-LVEF becomes pathologic it is possible to avoid severe and irreversible CHF.

Association of CEA test and liver scan in detection of hepatic metastases of gastrointestinal carcinoma.

The authors evaluate the combined use of liver scan and the CEA test in the diagnosis of hepatic metastases of carcinoma of the gastrointestinal tract. Association of the two tests is justified by the fact that the liver scan is very specific but not very sensitive, whereas the CEA test is more sensitive and not very specific. The sensitivity of the CEA test, on the other hand, can be increased by increasing the threshold of normality. However, the associated diagnostic use of the liver scan and the CEA test gives a loss of specificity with respect to the use of the liver scan alone. The present study, carried out on a series of 376 patients affected by gastrointestinal tumors of which 79 were of the stomach (9 with hepatic metastases), 133 of the colon and higher sigmoid (25 with hepatic metastases), and 164 of the lower sigmoid and rectum (29 with hepatic metastases), proposed to establish by use of a statistical method the optimal threshold of the CEA test that would give the best diagnostic specificity of the combined CEA test and liver scan without any relevant loss of sensitivity. A threshold of 26 ng/ml of the CEA test and gave a specificity of 92%, a sensitivity of 80%, and an accuracy of 90%. The authors think that in the detection of liver metastases of gastrointestinal tumors, the combined test can be more helpful the less the probability, for a given patient, for other metastatic localizations.

Tumor radioimmunolocalization in a murine system using monoclonal antibodies.

Tumor localization was obtained in a murine system by use of 131I-labeled monoclonal antibodies, both of IgG and IgM class. The A6 IgG2 monoclonal antibody (which recognizes the gp70 of MuLV) and the B3 IgM monoclonal antibody (which recognizes a proteic structure widely exposed on chemically induced tumors), which both manifest an in vitro cytotoxic activity for various types of murine lymphomas, were injected in tumor-bearing (B6 X BALB/c)F1 mice and B6 mice, respectively, at the dose of 1 microgram per mouse. The radioactivity count demonstrated an optimal tumor accumulation of the radiolabeled monoclonal antibodies 96 h after iodine injection, although an initial accumulation was already present 48 h after injection. The scanning detection was less sensitive, since at 48 h no tumor localization was possible. In the experiments with the A6 antibody, the presence of the gp70 in the circulating form, demonstrated by the detection of immunocomplexes in kidney and spleen of tumor-bearing mice injected with the A6, did not prevent radioactivity accumulation in the tumor. This accumulation was found to increase with tumor size only up to 1 g of tumor weight, then a decreased binding index was observed, whereas in the kidney the accumulation was progressive and paralleled the increase in tumor weight.

[Angiocardioscintigraphy in the cardiological surveillance of chemotherapy with anthracyclines]. / La angiocardioscintigrafia nella sorveglianza cardiologica della chemioterapia con antracicline.

Equilibrium angiocardioscintigraphy is a noninvasive nuclear medical method which allows cardiac function to be assessed. It is widely used in oncology since some clinically important drugs used in antitumor chemotherapy have a marked cardiotoxic effect. Angiocardioscintigraphy enables several parameters characteristic of cardiac function to be assessed, namely the left ventricular ejection fraction whose alterations during chemotherapy allow possible cardiotoxic side effects to be revealed before the development of irreversible heart failure.