Comparison of somatostatin receptor imaging, computed tomography and ultrasound in the clinical management of neuroendocrine gastro-entero-pancreatic tumours

(131)I-MIBG radionuclide therapy is safe and cost-effective in the control of symptoms of the carcinoid syndrome

BACKGROUND

The standard treatment used to control the symptoms of carcinoid syndrome (CS) involves subcutaneous injections of the somatostatin analogue octreotide. This is expensive (US $8000--16,000 per year), and treatment may be for many years. The aim of this study was to evaluate the efficacy and cost-effectiveness of our experience over the last 5 years with 1-131-labelled metaiodobenzylguanidine (MIBG) radionuclide therapy in the palliation of patients with CS.

METHODS

A consecutive series of 20 symptomatic patients (referred between 1994 and 1999) with CS were evaluated. Fifteen of them underwent(123)I-MIBG scanning. Of the 13 patients with significant tracer uptake in metastatic deposits compared to background, 12 underwent a course of therapeutic(131)I-MIBG (one patient refused). Symptoms, biochemical markers, CT scans, follow-up(123)I-MIBG scans, and the requirement for octreotide were used to assess outcome of treatment. Costs of(131)I-MIBG and octreotide treatments were compared.

RESULTS

MIBG treatment was well tolerated in all with only transient side-effects. Ten patients showed a measurable clinical improvement. Seven had a complete clinical response. The mean duration of response was 15.4 months. Octreotide was not required or was reduced in eight patients. Treatment with(131)I-MIBG resulted in a saving of US $1000 per patient, with effective symptom control, when compared to octreotide.

CONCLUSION

1-131 MIBG therapy is a safe and cost-effective therapeutic option to successfully control symptoms in patients with carcinoid syndrome.

Positron emission tomography (PET) and other nuclear medicine modalities in staging gastrointestinal cancer

Gastrointestinal (GI) cancers account for the second highest number of new tumor cases and deaths per year in the United States and Western Europe. The most frequently involved sites are, in descending order, the colorectum, stomach, pancreas, liver, bile duct, and esophagus. The most common tumor type is adenocarcinoma. Among the epithelial cancers, great attention has recently been given to the tumors of neuroendocrine origin. These concepts are relevant because nuclear medicine imaging is based on visualization by means of a particular uptake of radiolabelled tracers in cancer cells that concentrate the radioactive signal. This signal is detected and reconstructed in planar or tomographic images. Different radiopharmaceuticals have been proposed for diagnostic application in oncology (such as radiolabelled monoclonal antibodies (MAbs), receptor tracers, and positron-emitting radiopharmaceuticals), and they are currently used as tracers for tumor detection with different modalities and techniques. Most of these techniques demonstrate their clinical usefulness in the diagnosis of GI cancer. This work is not intended to be a comprehensive review of all the extensive experience and possibilities of nuclear medicine for the diagnosis of GI tumors; rather, it aims to summarize the current status of the most important approaches and their main indications in staging GI cancers.

Carcinoid and pancreatic endocrine tumors: recent advances in molecular pathogenesis, localization, and treatment

Neuroendocrine tumors include carcinoids and pancreatic endocrine tumors, which share a number of common features in their pathology, ability to cause clinical symptoms due to ectopic hormone and bioamine release, localization methods, and treatment. Although generally slow growing, a proportion demonstrate aggressive tumor growth. Therefore, in many cases treatment must be directed against both the tumor and the hormone-excess state. There have been significant recent advances into their molecular pathogenesis, natural history, and prognostic factors; clinical presentation defined by larger series analysis; localization methods; and the development of new treatments directed against the tumor and to control the hormone-excess state (including depot somatostatin analogues, interferon combinations, embolization, chemoembolization, radiotherapy with novel somatostatin analogues, and liver transplantation). Recent advances in each of these areas are briefly discussed.