18F-FLT and 125I-IdUrd uptake increase in human tumour cell lines induced by the thymidylate synthase inhibitor FdUrd.

AIM: 5-fluoro-2'-deoxyuridine (FdUrd) depletes the endogenous 5'-deoxythymidine triphosphate (dTTP) pool. We hypothesized whether uptake of exogenous dThd analogues could be favoured through a feedback enhanced salvage pathway and studied the FdUrd effect on cellular uptake of 3'-deoxy-3'-18F-fluorothymidine (18F-FLT) and 5-125I-iodo-2'-deoxyuridine (125I-IdUrd) in different cancer cell lines in parallel. METHODS: Cell uptake of 18F-FLT and 125I-IdUrd was studied in 2 human breast, 2 colon cancer and 2 glioblastoma lines. Cells were incubated with/without 1 µmol/l FdUrd for 1 h and, after washing, with 1.2 MBq 18F-FLT or 125I-IdUrd for 0.3 to 2 h. Cell bound 18F-FLT and 125I-IdUrd was counted and expressed in % incubated activity (%IA). Kinetics of 18F-FLT cell uptake and release were studied with/without FdUrd modulation. 2'-3H-methyl-fluorothymidine (2'-3H-FLT) uptake with/without FdUrd pretreatment was tested on U87 spheroids and monolayer cells. RESULTS: Basal uptake at 2 h of 18F-FLT and 125I-IdUrd was in the range of 0.8-1.0 and 0.4-0.6 Bq/cell, respectively. FdUrd pretreatment enhanced 18F-FLT and 125I-IdUrd uptake 1.2-2.1 and 1.7-4.4 fold, respectively, while co-incubation with excess thymidine abrogated all 18F-FLT uptake. FdUrd enhanced 18F-FLT cellular inflow in 2 breast cancer lines by factors of 1.8 and 1.6, respectively, while outflow persisted at a slightly lower rate. 2'-3H-FLT basal uptake was very low while uptake increase after FdUrd was similar in U87 monolayer cells and spheroids. CONCLUSIONS: Basal uptake of 18F-FLT was frequently higher than that of 125I-IdUrd but FdUrd induced uptake enhancement was stronger for 125I-IdUrd in five of six cell lines. 18F-FLT outflow from cells might be an explanation for the observed difference with 125I-IdUrd.

Positron Emission Tomography and Computer Tomography (PET/CT) in Prostate, Bladder, and Testicular Cancers

Positron emission computed tomography (PET) is a functional, noninvasive method for imaging regional metabolic processes that is nowadays most often combined to morphological imaging with computed tomography (CT). Its use is based on the well-founded assumption that metabolic changes occur earlier in tumors than morphologic changes, adding another dimension to imaging. This article will review the established and investigational indications and radiopharmaceuticals for PET/CT imaging for prostate cancer, bladder cancer and testicular cancer, before presenting upcoming applications in radiation therapy.

Fluorodeoxyuridine mediated cell cycle synchronization in S-phase increases the Auger radiation cell killing with 125I-iododeoxyuridine.

AIM: 125I-iododeoxyuridine is a potential Auger radiation therapy agent. Its incorporation in DNA of proliferating cells is enhanced by fluorodeoxyuridine. Here, we evaluated therapeutic activities of 125I-iododeoxyuridine in an optimized fluorodeoxyuridine pre-treatment inducing S-phase synchronization. METHODS: After S-phase synchronization by fluorodeoxyuridine, cells were treated with 125I-iododeoxyuridine. Apoptosis analysis and S-phase synchronization were studied by flow cytometry. Cell survival was determined by colony-forming assay. Based on measured growth parameters, the number of decays per cell that induced killing was extrapolated. RESULTS: Treatment experiments showed that 72 to 91% of synchronized cells were killed after 0.8 and 8 kBq/ml 125I-iododeoxyuridine incubation, respectively. In controls, only 8 to 38% of cells were killed by corresponding 125I-iododeoxyuridine activities alone and even increasing the activity to 80 kBq/ml gave only 42 % killing. Duplicated treatment cycles or repeated fluorodeoxyuridine pre-treatment allowed enhancing cell killing to >95 % at 8 kBq/ml 125I-iododeoxyuridine. About 50 and 160 decays per S-phase cells in controls and S-phase synchronization, respectively, were responsible for the observed cell killing at 0.8 kBq/ml radio-iododeoxyuridine. CONCLUSION: These data show the successful application of fluorodeoxyuridine that provided increased 125I-iododeoxyuridine Auger radiation cell killing efficacy through S-phase synchronization and high DNA incorporation of radio-iododeoxyuridine.

MIBG scintigraphy for the diagnosis and follow-up of children with neuroblastoma.

Neuroblastoma (NBL) is the commonest extra-cranial solid tumor in children and the leading cause of cancer related deaths in childhood between the age of 1 to 4 years. NBL may behave in very different ways, from the less aggressive stage 4S NBL or congenital forms that may resolve without treatment in up to 90% of the children, to the high-risk disseminated stage 4 disease in older children with a cure rate of 35 to 40%. Initial staging is crucial for effective management and radiolabeled metaiodobenzylguanidine (MIBG) with iodine-123 is a powerful tool with a sensitivity around 90% and a specificity close to 100% for the diagnosis of NBL. MIBG scintigraphy is used routinely and is mandatory in most investigational clinical trials both for the initial staging of the disease, the evaluation of the response to treatment, as well as for the detection of recurrence during follow-up. With respect to outcome of children presenting disseminated stage 4 NBL, the role of post-therapeutic [(123)I]MIBG scan has been investigated by several groups but so far there is no consensus whereas a complete or very good partial response as assessed by MIBG may be of prognostic value. NBL needs a multimodality approach at diagnosis and during follow-up and MIBG scintigraphy keeps its pivotal role, in particular with respect to bone marrow involvement and/or cortical bone metastases.

[Cardiac imaging: specific clinical role of newly developed non invasive techniques. Part 1: Morphological evaluation]. / Imagerie cardiaque non invasive: apport spécifique en clinique des nouvelles modalités (I). Evaluation morphologique.

Echocardiography is the preferred initial test to assess cardiac morphology and ventricular function. Cardiac MRI enables an optimal visualisation of heart muscle without contrast injection, and precise measurement of the ventricular volumes and systolic function. It is therefore an ideal test for patients with poor echocardiographic windows or for the specific evaluation of right heart chambers. Heart CT also remarkably images heart muscle and precisely measures ventricular systolic function after intravenous injection of iodinated contrast. Coronary CT may also, in selected cases, avoid the need for diagnostic coronary angiography. Although very accurate, these imaging modalities are expensive and may be contra-indicated for a particular patient. Their use in clinical practice has to follow the accepted guidelines.

[Cardiac imaging: specific clinical role of newly developed non invasive techniques. Part II: functional evaluation]. / Imagerie cardiaque non invasive: apport spécifique en clinique des nouvelles modalités (II). Evaluation fonctionnelle.

The non-invasive evaluation of myocardial ischemia is a priority in cardiology. The preferred initial non-invasive test is exercise ECG, because of its high accessibility and its low cost. Stress radionuclide myocardial perfusion imaging or stress echocardiography are now routinely performed, and new non-invasive techniques such as perfusion-MRI, dobutamine stress-MRI or 82rubidium perfusion PET have recently gained acceptance in clinical practice. In the same time, an increasing attention has been accorded to the concept of myocardial viability in the decisional processes in case of ischemic heart failure. In this indication, MRI with late enhancement after intravenous injection of gadolinium and 18F-FDG PET showed an excellent diagnostic accuracy. This article will present these new imaging modalities and their accepted indications.

Sentinel lymph node involvement and a high Breslow index are independent factors of risk for early relapse of melanoma.

AIM: The clinical relevance of sentinel lymph node (SLN) analysis was evaluated prospectively and compared with other known risk factors of relapse in early stage melanoma. METHODS: Surgery was guided by lymphoscintigraphy, blue dye and gamma probe detection. SLN were analysed by haematoxylin eosin (HE) histochemistry and multimarker immunohistochemistry (IHC). Disease free survival (DFS) was evaluated with Kaplan-Meier plots according to different parameters and Cox analyses of variance. RESULTS: From 210 patients a total of 381 SLN were excised. Lymphoscintigraphy identified all excised SLN with only 2 false positive lymphatic lakes. Fifty patients (24%) had tumour positive SLN. With a mean follow-up of 31.3 months, 29 tumour recurrences were observed, 19 (38%) in 50 SLN positive and 10 (6%) in 160 SLN negative patients. Strong predictive factors for early relapse (p < 0.0005) were SLN positivity and a high Breslow index. CONCLUSION: SLN tumour positivity is an independent factor of high risk for early relapse with a higher power of discrimination than the Breslow index.

SPECT myocardial perfusion imaging: long-term prognostic value in diabetic patients with and without coronary artery disease.

AIM: To determine the long-term prognostic value of SPECT myocardial perfusion imaging (MPI) for the occurrence of cardiovascular events in diabetic patients. PATIENTS, METHODS: SPECT MPI of 210 consecutive Caucasian diabetic patients were analysed using Kaplan-Meier event-free survival curves and independent predictors were determined by Cox multivariate analyses. RESULTS: Follow-up was complete in 200 (95%) patients with a median period of 3.0 years (0.8-5.0). The population was composed of 114 (57%) men, age 65 +/- 10 years, 181 (90.5%) type 2 diabetes mellitus, 50 (25%) with a history of coronary artery disease (CAD) and 98 (49%) presenting chest pain prior to MPI. The prevalence of abnormal MPI was 58%. Patients with a normal MPI had neither cardiac death, nor myocardial infarction, independently of a history of coronary artery disease or chest pain. Among the independent predictors of cardiac death and myocardial infarction, the strongest was abnormal MPI (p < 0.0001), followed by history of CAD (Hazard Ratio (HR) = 15.9; p = 0.0001), diabetic retinopathy (HR = 10.0; p = 0.001) and inability to exercise (HR = 7.7; p = 0.02). Patients with normal MPI had a low revascularisation rate of 2.4% during the follow-up period. Compared to normal MPI, cardiovascular events increased 5.2 fold for reversible defects, 8.5 fold for fixed defects and 20.1 fold for the association of both defects. CONCLUSION: Diabetic patients with normal MPI had an excellent prognosis independently of history of CAD. On the opposite, an abnormal MPI led to a >5-fold increase in cardiovascular events. This emphasizes the value of SPECT MPI in predicting and risk-stratifying cardiovascular events in diabetic patients.

Ovarian cancer management. Practice guidelines for nuclear physicians.

Ovarian cancer is a frequent and severe malignancy. Over 75% of cases are diagnosed at an advanced stage with disease spread beyond the ovaries. Despite the high response rates of initial treatments (i.e.,70-80%), the median progression-free survival of advanced ovarian cancer is 16-22 months, and the 5-year overall survival, 20-30%. The majority of these patients relapse, with metastatic peritoneal spread, unresectable, or drug resistant disease. Our goal was to outline current knowledge about diagnosis, prognostic factors, and treatments, and to dwell on non-nuclear medicine and nuclear-medicine diagnostic procedures.

Nuclear medicine procedures and neuroblastoma in childhood. Their value in the diagnosis, staging and assessment of response to therapy.

Neuroblastoma is a frequent tumor of childhood and remains a leading cause of death despite treatment intensification. Many clinical, biological and genetic factors have been identified and are associated with prognosis and outcome after treatment. Initial staging plays a major role for determining the therapeutic strategy. Radioiodinated metaiodobenzylguanidine (MIBG) scintigraphy is a highly sensitive and specific method for diagnosing, staging and also monitoring response to therapy. In children with high-risk neuroblastoma, relapse may occur any time after remission has been obtained. (123)I-MIBG scintigraphy is a reliable method to follow-up those children and allows early detection of recurrence. As far as outcome is concerned, MIBG scintigraphy has not proven to have any prognostic value. Other radiolabeled tracers, such as pentetreotide, monoclonal antibodies, and sestamibi have been compared with MIBG. Up to now, no method has demonstrated a reliable prognostic value, even though neuroblastoma that express somatostatin receptor seem to have a better clinical outcome and survival rate. Positron emission tomography (PET) with (18)F-fluorodeoxyglucose has been used successfully in staging and monitoring response to treatment of MIBG negative tumors. (11)C-hydroxyephedrine has shown promising results in staging neuroblastoma, but is not as widely available as MIBG. With respect to biological and genetic factors, nuclear medicine procedures play a major role in initial diagnosis and staging of neuroblastoma. At the moment, MIBG scintigraphy is certainly the most sensitive and specific method for initial staging of the disease, as well as monitoring the response to treatment and detecting early relapse.

The value of bone marrow scintigraphy using 99mTc monoclonal antigranulocyte antibodies in complement to bone scintigraphy in detecting bone metastases from primary breast cancer.

This prospective study evaluates bone marrow scintigraphy (BMS) in detecting bone metastases from primary breast cancer when performed in complement to conventional bone scan (BS). Sixty women predominantly with low-stage disease underwent BS followed by BMS within 1-35 days using BW250/183 antigranulocyte antibodies. A receiver operating characteristic (ROC) analysis was performed to compare BS to BS+BMS on a patient-by-patient basis using a 'gold standard' composed of subsequent computed tomography, magnetic resonance imaging, X-ray or BS examinations and at least a 12 month follow-up. Metastases were present in eight out of 60 patients (13%). Specificity was improved by BS+BMS compared to BS alone (90%, 65%) as well as positive predictive value (62%, 27%), accuracy (87%, 72%), positive (10.4, 2.4) and negative (0.20, 0.00) likelihood ratios. Sensitivity (100%, 88%) and negative predictive value (100%, 97%) were similar for BMS+BS and BS alone. As a result of BMS, clinical management was modified in 15 patients (25%). In conclusion, BMS supplements BS by improving specificity, positive predictive value and accuracy in detecting breast cancer bone metastases. The ROC curves show improved specificity for BS+BMS at the same sensitivity compared to BS alone. Consequently, BMS may be useful in low-stage subjects with positive or equivocal BS for metastases.

Editorial perspective--advances in B-cell non-Hodgkin's lymphoma.

Radioimmunotherapy (RIT) represents an exciting new therapeutic option for the treatment of B-cell non-Hodgkin's lymphoma (NHL), emerging at a time when significant advances have been made in NHL classification, molecular genetics and treatment. Despite recent treatment advances, including the use of fludarabine phosphate-based combination chemotherapies, able to eradicate minimal residual disease, there remains much room for improvement. The incorporation of RIT into treatment schedules is an attractive option to exploit the extreme sensitivity of lymphoma cells to irradiation. In this supplement, we examine the potential future roles for RIT in the light of past and present therapies, existing RIT clinical data and the unique attributes of radiolabeled monoclonal antibodies.

Limb salvage by neoadjuvant isolated perfusion with TNFalpha and melphalan for non-resectable soft tissue sarcoma of the extremities.

AIMS: Patients with non-resectable soft tissue sarcomas of the extremities do not live longer if they are treated by amputation or disarticulation. In order to avoid major amputations, we tested isolated limb perfusion (ILP) with tumour necrosis factor alpha (TNF)+melphalan+/-interferon-gamma (IFN) as a pre-operative, neoadjuvant limb salvage treatment. METHODS: Twenty-two patients were included (six men and 16 women; three upper limb and 19 lower limb tumours). The AJCC stage was IIA in four patients, III in seven and IV in 11. Thirteen cases were recurrent or progressive after previous therapy; five tumours had a diameter >/=20 cm, and four were multiple or regionally metastatic. There were six malignant fibrous histiocytomas, five liposarcomas, four malignant peripheral nerve sheath tumours, three rhabdomyosarcomas, two leiomyosarcomas, one recurrent extraskeletal osteosarcoma and one angiosarcoma. RESULTS: Twenty-four ILPs were performed in the 22 patients, and 18 (82%) experienced an objective response: this was complete in four (18%) and partial in 14 (64%). Three patients had a minimal or no response and the tumour progressed in one case. All patients had fever for 24 hours but only one developed a reversible grade 3 distributive shock syndrome with no sequelae. There was no grade 4 toxicity. Seventeen patients (77%) underwent limb-sparing resection of the tumour remnants after a median time of 3.4 months: 10 resections were intracompartmental and seven extracompartmental. Surgery included flaps or skin grafts in five patients, arterial replacement in two and knee arthrodesis in one. Adjuvant chemotherapy was given to eight patients and radiotherapy to six. In one patient amputation was necessary after a second ILP. Secondary amputations were performed for recurrence in two patients, resulting in an overall limb salvage rate of 19/22 (86%). After a median follow-up of 18.7 months, 10 recurrences were recorded: seven were both local and systemic and three were only local. The median disease free and overall survival times have been >12.5 and 18.7 months respectively: this is similar to the outcome after primary amputations for similar cases. CONCLUSION: ILP with TNF and chemotherapy is an efficient limb sparing neoadjuvant therapy for a priori non-resectable limb soft tissue sarcomas.

[Sentinel lymph node biopsy in breast cancer: the Lausanne experience]. / La biopsie du ganglion sentinelle en cas de cancer du sein: l'expérience Lausannoise.

A total of 40 patients (mean age 51 yrs; 36-89 yrs) with clinically T1-T2(< 3 cm)N0M0 breast cancer underwent sentinel node (SN) mapping with radioactive tracer (99mTc) injection only in 21 patients, with Patent blue V in 1 patient, or with both techniques in 19 patients. The preoperative injection of 99mTc (20-40 MBq) was followed by lymphoscintigraphy. A handheld gamma probe was used to detect the SN in the operative room. A lumpectomy and an axillary dissection were performed in all the patients. SNs could be identified in 39/40 patients, resulting in a sensitivity of 98%. Successful localization of the SNs was accomplished by isotope only in 19/20 patients, by blue dye only in 1/1 patient, and by both methods in 19/19 patients; in 2 of these 19 patients, SNs were identified by blue dye only. Axillary metastases were found in 12/40 patients (30%), the SN being the only nodal metastasis in 8/12 patients (75%). Six of these 12 patients (50%) had only evidence of micrometastasis. Negative SNs on serial sections stained with hematoxylin-eosin (H&E) were evaluated with cytokeratin immunostain (C11). In all cases of negative SNs the remaining axillary nodes were also free of tumor, resulting in a negative predictive value of 100%. We conclude that SN mapping is a highly accurate method for staging the axillary node status in breast cancer patients. Optimal localization is achieved by the combination of injection of 99mTc-colloid and blue dye as evidence by the cases of positive SN identified by only one of both methods.

Effect of thrombin inhibition on synovial inflammation in antigen induced arthritis.

OBJECTIVE: To determine the effect of the thrombin inhibitor, hirudin, on the pathogenesis of murine antigen induced arthritis (AIA). METHODS: AIA was induced by intra-articular injection of methylated bovine serum albumin in the knee joints of previously immunised mice. Hirudin (injected subcutaneously 3 x 200 microg/mouse/day) was given over 13 days, starting three days before arthritis onset, and its anticoagulant effect monitored by clotting times. Arthritis severity was evaluated by technetium-99m ((99m)Tc) uptake in the knee joints and by histological scoring. In addition, intra-articular fibrin deposition was examined by immunohistochemistry, and synovial cytokine mRNA expression measured by RNase protection. RESULTS: Joint inflammation, measured by (99m)Tc uptake, was significantly reduced in hirudin treated mice at days 7 and 10 after arthritis onset. Histologically, synovial thickness was markedly decreased in hirudin treated mice compared with untreated ones. By contrast, no difference in articular cartilage proteoglycan content was found between both groups. Intra-articular fibrin deposition and synovial interleukin 1beta mRNA levels, were slightly reduced ( approximately 20%) in arthritic joints from hirudin treated mice compared with untreated ones at day 10 of AIA. CONCLUSION: Hirudin reduces joint inflammation associated with AIA by fibrin-dependent and independent mechanisms.

Radioimmunoimaging and radioimmunotherapy: will these be routine procedures?

Despite major progress made during the past 25 years in the genetic engineering and labeling of monoclonal antibodies (Mab) and in the understanding of the uptake and kinetics of radiolabeled Mab by normal and tumor tissues, immunoscintigraphy never succeeded in becoming a routine procedure, compared with a bone or gallium scan. The more and more generalized availability of positron emission tomography (PET) with Fluorine-18 fluorodeoxyglucose (FDG) for diagnosis and staging of malignant diseases will probably definitively seal the fate of radioimmunodiagnosis as it has been conceived up until now. With respect to the nonspecificity of deoxyglucose uptake by tumor cells, it is not to be excluded that antibodies, or more likely antibody fragments, labeled with positron emitters might be used for tissue characterization. The recent success of radioimmunotherapy, especially in B-cell malignancies, entitles us to expect that RIT will become part of standard therapy of patients with malignancies. In that case, immunoscintigraphy will be needed for treatment planning (patient selection and dosimetry). One might even speculate that the oncologists who are becoming familiar with nuclear medicine tracer techniques for pretreatment evaluation might be interested in extending them to distribution and kinetic studies of other cytotoxic drugs. The close cooperation between nuclear medicine specialists, oncologists, and hematologists is essential to make radioimmunotherapy a routine procedure.

Role of lipase in the regulation of postprandial gastric acid secretion and emptying of fat in humans: a study with orlistat, a highly specific lipase inhibitor.

BACKGROUND AND AIMS: To investigate the importance of lipase on gastric functions, we studied the effects of orlistat, a potent and specific inhibitor of lipase, on postprandial gastric acidity and gastric emptying of fat. METHODS: Fourteen healthy volunteers participated in a double blind, placebo controlled, randomised study. In a two way cross over study with two test periods of five days, separated by at least 14 days, orlistat 120 mg three times daily or placebo was given with standardised daily meals. In previous experiments we found that this dose almost completely inhibited postprandial duodenal lipase activity. Subjects underwent 28 hour intragastric pH-metry on day 4, and a gastric emptying study with a mixed meal (800 kcal) labelled with (999m)Tc sulphur colloid (solids) and (111In)thiocyanate (fat) on day 5. Gastric pH data were analysed for three postprandial hours and the interdigestive periods. RESULTS: Orlistat inhibited almost completely (by 75%) lipase activity and accelerated gastric emptying of both the solid (by 52%) and fat (by 44%) phases of the mixed meal (p<0.03). Orlistat increased postprandial gastric acidity (from a median pH of 3.3 to 2.7; p<0.01). Postprandial cholecystokinin release was lower with orlistat (p<0.03). CONCLUSION: Lipase has an important role in the regulation of postprandial gastric acid secretion and fat emptying in humans. These effects might be explained by lipolysis induced release of cholecystokinin.