The quarterly journal of nuclear medicine : official publication of the Italian Association of Nuclear Medicine (AIMN) [and] the International Association of Radiopharmacology (IAR)
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Multicenter Study Clinical Trial
Radionuclide therapy for painful bone metastases. An Italian multicentre observational study. Writing Committee of an Ad Hoc Study Group.
It has been affirmed that observational studies give analogous results to randomised controlled ones. ⋯ Bearing in mind that observational studies can provide just as accurate results as randomised controlled trials, this study confirms the main findings of various limited monocentre trials.
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Comparative Study
Clinical trials of cost effectiveness in technology evaluation.
This article discusses models of efficacy, design of clinical trials and the role of mathematical modeling in diagnostic technology evaluation and determination of cost-effectiveness. A multi-tiered model of efficacy, which views diagnostic imaging as part of a global process of patient management and outcome, has been described. The first tier involves imaging efficacy, which must be determined by clinical trial. ⋯ Decision analysis is easier and less expensive to perform than clinical trials, and results are easily generalizable to other settings. Disadvantages arise from the nondescriptive nature of modeling and lack of transparency, which make it difficult to evaluate the appropriateness of decision tree structures and input data. Modeling is an unavoidable fact of life in technology evaluation, since the resources that would be required for full evaluation of imaging modalities by clinical trial are not available.
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Neuroendocrine gastroenteropancreatic tumors are rather rare neoplasms with an incidence of 1-2 cases per 100,000 people. They show rather varying tumor biology and present sometimes distinct clinical symptoms such as flushing, diarrhoea, hypoglycemia and gastric ulcers. The biochemical diagnosis is today significantly improved by the introduction of chromogranin A as a general tumor marker, which is also useful in histopathology. ⋯ Somatostatin analogues will always be combined with the other two alternatives to reduce clinical symptoms. Chemotherapy is particularly useful for patients with more aggressive tumors with high proliferation capacity, whereas alpha interferon is beneficial in classical midgut carcinoids with low proliferation capacity. Quite recently somatostatin based radioactive tumor targeted treatment has evolved with preliminary promising data but further studies are needed to deliniate its future role in the treatment of neuroendocrine tumors in patients.
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In vitro data have demonstrated a high amount of receptors for various hormones and peptides on malignant cells of neuroendocrine origin. Among these, binding sites for members of the SST-family (hSSTR1-5) are frequently found, and their expression has led to therapeutic and diagnostic attempts to specifically target these receptors. Receptor scintigraphy using radiolabeled peptide ligands has proven its effectiveness in clinical practice. ⋯ This new therapy could offer palliation and disease control at a reduced cost. The final peptide therapy strategy is most probably cheaper than conventional radiotherapies or prolonged chemotherapies. Overall, receptor-mediated radiotherapy with 90Y-DOTA-lanreotide/90Y-DOTA-DPhe1-Tyr3-octre otide might also be effective in patients refractory to conventional strategies.
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The aim of radioimmunotherapy in treating solid tumors is to target tumor sites while sparing normal tissues. This can best be achieved by using a monoclonal antibody (MAb) with high tumor uptake and rapid clearance. Because MAbs are basic, positively charged proteins, and mammalian cells are negatively charged, the electrostatic interactions between the two can create higher levels of background binding resulting in low tumor to normal organ ratios. ⋯ Several groups have reported on the effects of chemical modification using molecules such as dextran, PEG, lactose and biotin. Some of these modified MAbs retain the antigen binding specificity of the parent molecule and have improved clearance characteristics from blood and other organs. Hence, these methods can be used to improve both the diagnostic and therapeutic potential of MAbs by improving the signal to noise ratio and the absolute tumor accretion of MAb, respectively.