Measurable Serum Estradiol and Estrone in Women 36-56 Years During Adjuvant Treatment With Aromatase Inhibitors for a Hormone Receptor-Positive Breast Cancer. Case Studies and Cross-sectional Study Using an Ultra-sensitive LC-MS/MS-Method

BACKGROUND AND PURPOSE

Ovarian function recovery (OFR) during adjuvant use of an aromatase inhibitor (AI) negatively impacts breast cancer outcome. We measured serum FSH and estrogen levels in consecutive AI-users with an uncertain menopausal status during follow-up and report associated risk factors of OFR METHODS: A retrospective cross sectional observational monocentric study including breast cancer patients in follow-up using an adjuvant AI, age 36 to 56 years, with at least one serum estradiol (E2) and estrone (E1) measurement between 2013 and 2020. Estrogens were quantified using a sensitive liquid chromatography-tandem mass spectrometry method (LC-MS/MS). Women on LHRH agonist were included while those with a bilateral oophorectomy or ovarian irradiation were not. We aimed to identify risk factors of OFR considering age, body mass index (BMI), previous chemotherapy and duration of AI use. Univariable analysis was used to evaluate risk factors of OFR.

RESULTS

E2/E1 levels were assessed in 207 patients with a median age of 50 years (range 36-56). 17 of 159 on AI (10.7%) and 3 of 48 on AI + LHRH (6.3%) had OFR. Seven out of 17 patients (41,2%) with OFR in the AI only group and 2 out of 3 patients (66,7%) in the AI+LHRH agonist group were in amenorrhea. Age <50 y and adjuvant chemotherapy were statistically significantly different between the OFR group and the group with postmenopausal estrogen levels.

CONCLUSION

Breast cancer patients aged 36 to56 years need to be monitored closely during adjuvant treatment with aromatase inhibitors: to confirm menopausal status, to evaluate compliance and to ensure ovarian activity remains adequately suppressed. Estrone might be a better marker then estradiol to detect ovarian reactivation.

Free Testosterone Reflects Metabolic as well as Ovarian Disturbances in Subfertile Oligomenorrheic Women

BACKGROUND

Diagnosing polycystic ovary syndrome (PCOS) is based on ovulatory dysfunction, ovarian ultrasound data, and androgen excess. Total testosterone is frequently used to identify androgen excess, but testosterone is mainly bound to sex hormone-binding globulin (SHBG) and albumin. Only 1-2% of nonprotein-bound testosterone (so-called free testosterone) is biologically active and responsible for androgen action. Moreover, automated immunoassays which are frequently used for female testosterone measurements are inaccurate.

OBJECTIVE

To assess the clinical usefulness of liquid chromatography-tandem mass spectrometry measured testosterone and calculated free testosterone in subfertile women attending a fertility clinic with oligomenorrhea and suspected PCOS.

METHODS

Hormonal and metabolic parameters were evaluated, and ovarian ultrasound was performed. Total testosterone was measured by liquid chromatography-tandem mass spectrometry. Free testosterone was calculated from total testosterone and SHBG.

RESULTS

Sixty-six women were included in the study. Total testosterone was associated with ovarian volume and antral follicle count but not with metabolic parameters. However, SHBG and calculated free testosterone were associated with both ovarian ultrasound and metabolic parameters, such as BMI and insulin resistance.

CONCLUSIONS

Assessing SHBG and free testosterone is important in evaluating androgen excess in subfertile women with ovulatory dysfunction and suspected PCOS, as it reflects both ovarian and metabolic disturbances.

The effect of paternal methyl-group donor intake on offspring DNA methylation and birth weight

Most nutritional studies on the development of children focus on mother-infant interactions. Maternal nutrition is critically involved in the growth and development of the fetus, but what about the father? The aim is to investigate the effects of paternal methyl-group donor intake (methionine, folate, betaine, choline) on paternal and offspring global DNA (hydroxy)methylation, offspring IGF2 DMR DNA methylation, and birth weight. Questionnaires, 7-day estimated dietary records, whole blood samples, and anthropometric measurements from 74 fathers were obtained. A total of 51 cord blood samples were collected and birth weight was obtained. DNA methylation status was measured using liquid chromatography-tandem mass spectrometry (global DNA (hydroxy)methylation) and pyrosequencing (IGF2 DMR methylation). Paternal betaine intake was positively associated with paternal global DNA hydroxymethylation (0.028% per 100 mg betaine increase, 95% CI: 0.003, 0.053, P=0.03) and cord blood global DNA methylation (0.679% per 100 mg betaine increase, 95% CI: 0.057, 1.302, P=0.03). Paternal methionine intake was positively associated with CpG1 (0.336% per 100 mg methionine increase, 95% CI: 0.103, 0.569, P=0.006), and mean CpG (0.201% per 100 mg methionine increase, 95% CI: 0.001, 0.402, P=0.049) methylation of the IGF2 DMR in cord blood. Further, a negative association between birth weight/birth weight-for-gestational age z-score and paternal betaine/methionine intake was found. In addition, a positive association between choline and birth weight/birth weight-for-gestational age z-score was also observed. Our data indicate a potential impact of paternal methyl-group donor intake on paternal global DNA hydroxymethylation, offspring global and IGF2 DMR DNA methylation, and prenatal growth.

Comparison of molecular responses based on BCR-ABL1% (IS) results from an in-house TaqMan-based qPCR versus Xpert(®) assay in CML patients on tyrosine kinase inhibitor therapy

OBJECTIVES

Tyrosine kinase inhibitors (TKIs) have drastically changed the prospects for chronic myeloid leukemia (CML) patients. The European LeukemiaNet (ELN) recommends molecular monitoring of BCR-ABL1 mRNA levels at distinct time points to define an optimal response, warning, or failure of treatment.

METHODS

Sixty-four follow-up peripheral blood samples from CML patients on TKI were tested by two methods. Molecular responses based on BCR-ABL1% (IS) from an Xpert(®) BCR-ABL1 Monitor assay were compared with TaqMan-based qPCR.

RESULTS

Seven samples showed 'molecularly undetectable leukaemia' by both methods (11%). In-house qPCR showed 57 BCR-ABL1+ samples; 45/57 samples (79%) were concordant for 'major molecular response' (MMR, n = 32) and 'no MMR' (n = 13) by both assays, whereas nine were BCR-ABL1 negative by Xpert(®). Identical molecular responses (i.e. 'optimal') were defined in 41 samples. Discordances seen in patients < 10 months on TKI (n = 2) had no impact on clinical management, whereas for patients >12 months on TKI, a different molecular response was defined ('warning' versus 'optimal'). Thirteen samples had 'no MMR' by both methods. 10/13 showed identical intervals (>10%(IS), 1-10%(IS) or 0·1-1%(IS)), corresponding to seven 'failures' and three 'warnings'. Discordant intervals were seen in 3/13 samples (all defined as 'failures'). Deep molecular responses (MR(4·0) or MR(5·0)) with detectable BCR-ABL1 showed some fluctuations between both methods, nevertheless, all had 'optimal' responses. 'Molecularly undetectable leukaemia' was observed more frequently by Xpert(®) (n = 16) as by our in-house assay (n = 7).

DISCUSSION

Based on current ELN recommendations, Xpert(®) BCR-ABL1 assay defines identical molecular responses as TaqMan-based qPCR BCR-ABL1% (IS) data in 98% (63/64) of samples.

Aberrant glycated haemoglobin (HbA1c) results leading to haemoglobinopathy diagnosis in four Belgian patients

INTRODUCTION

We report four cases in which haemoglobinopathy screening was triggered following aberrant HbA1c analysis. Either the HbA1c assay was unable to produce a quantifiable result or it showed the presence of an extra fraction and/or the result was discordant with the clinical context.

CASE REPORT

In the reported four patients, all from Caucasian, Belgian descent, Hb analysis was performed using cation-exchange high performance liquid chromatography. If necessary, additional Hb electrophoresis was carried out to establish a preliminary (biochemical) diagnosis. Definitive diagnosis was obtained for every sample through DNA-analysis. Three patients were carriers of Hb J-Toronto and one of Hb Stanleyville-II.

DISCUSSION

This report underlines the importance of correct interpretation of HbA1c results to avoid mismanagement of (diabetic) patients. Since neither the RBC indices, the clinical context, nor the ethnicity of these patients was suspicious for an underlying haemoglobinopathy, the aberrant HbA1c result was the only indicator for further investigation. Laboratory personnel and clinicians should be aware of the possibility of uncommon, sometimes clinically unsuspected, Hb variants to cause aberrant HbA1c values, even in populations with low prevalence for haemoglobinopathies. Further analysis should be prompted to obtain definitive diagnosis. Alternative methods for monitoring glycaemic control should be used.

Evaluation of the Sebia Minicap Flex Piercing capillary electrophoresis for hemoglobinopathy testing

INTRODUCTION

Capillary zone electrophoresis (CZE) at alkaline pH is one of the techniques used for hemoglobinopathy screening. In this study, an evaluation of the performance of a lower throughput CZE instrument, the Sebia Minicap Flex Piercing system, for this purpose is reported for the first time.

METHODS

The analytical performance of the Sebia Minicap Flex Piercing system was evaluated. Furthermore, a method comparison between the Sebia Minicap Flex Piercing and two HPLC methods, that is, the Bio-Rad Variant Classic(™) and the Bio-Rad D-10(™) systems was performed by measuring samples with and without clinically relevant hemoglobin disorders.

RESULTS

The analytical performance was acceptable for the determination of HbA, HbA2, HbS, and HbF, with an imprecision ≤2.0%. Method comparison showed a linear correlation for HbA2, HbF, and HbS measurements. Clinical concordance was acceptable when comparing CZE and HPLC.

CONCLUSIONS

Lower throughput CZE using the Sebia Minicap Flex Piercing can be used for precise and accurate first line screening and follow-up of hemoglobinopathies.

Abstract P1-13-09: Sensitive liquid chromatography-tandem mass spectrometry method for serum estradiol and estrone assessment without derivatisation, overcoming cross reactivity with exemestane

Objective Measuring serum estrogen levels in postmenopausal women on oral aromatase inhibitors is important but challenging. Direct immunoassays are the most widely used techniques for measuring serum estradiol (E2) in research and clinical laboratories. Unfortunately, commercially available immunoassays for E2 lack precision and accuracy in the low range (&lt;20 ng/l) and are susceptible to interference. In addition, particularly in exemestane users biochemical monitoring of E2 is problematic because exemestane metabolites cross react in most immunoassays for E2. We developed a sensitive, routinely applicable liquid chromatography-tandem mass spectrometry (LC-MSMS) method for E2 and estrone (E1) quantification in human serum without the need for derivatization or an extended extraction protocol.

Materials and methods Serum E2 levels, assessed with LC-MSMS and electrochemiluminescence estradiol assay (ECLIA) on Modular E170 from Roche Diagnostics, of 10 breast cancer patients treated with exemestane were compared. Limit of quantification (LOQ) was 1.3 ng/l for LC-MSMS (coefficient of variation &lt;20% and signal-to-noise ratio &gt; 10, own validation) and 5 pg/ml for ECLIA (Roche, according to manufacturer).

Results Patients treated with exemestane showed much higher E2 levels when measured by ECLIA compared to E2 levels determined by LC-MSMS (Table 1). All patients, but one, had E2 values below LOQ when assessed with LC-MSMS whereas ECLIA measurements showed higher levels with a large variety (mean: 16.5 ng/l; range: 7-33 ng/l).

Results for E2 via ECLIA and LC-MSMS for patients treated with exemestanePatientE2 LC-MSMS ng/lE2 ECLIA ng/l1&lt;1.3212&lt;1.373&lt;1.3124&lt;1.3335&lt;1.3156&lt;1.3227&lt;1.398&lt;1.32692.51010&lt;1.310

Conclusion E2 levels in exemestane users measured with ECLIA from Roche are overestimated, probably due to cross reactivity of its metabolites. Therefore, this assay can not be used in these patients. Here, we demonstrate that this hurdle can be overcome by assessment of estrogen values with LC-MSMS. Our group was able to develop such a sensitive method, without derivatization.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-13-09.

Lifestyle after bariatric surgery: a multicenter, prospective cohort study in pregnant women

BACKGROUND

To ensure a good pregnancy outcome after bariatric surgery, a healthy life-style and a multidisciplinary prenatal follow-up is recommended. The aim of this prospective multicenter trial was to compare diet quality and physical activity (PA) of pregnant women with bariatric surgery with current lifestyle recommendations.

METHODS

Pregnant women (>18 years, prepregnancy BMI 28 ± 6 kg/m², 39 % nulliparae, 25 % smokers) with a history of bariatric surgery were recruited and allocated to two groups according to surgery type: restrictive (N = 18) and bypass group (N = 31). One 7-day dietary record and one Kaiser questionnaire on PA were collected during the first and second trimester. Dietary quality was assessed using the Healthy Eating Index.

RESULTS

The diet quality did not change during pregnancy (restrictive group p = 0.050; bypass group p = 0.975) and was comparable between groups (first trimester p = 0.426; second trimester p = 0.937). During the first trimester, 15 % of the pregnant women had a healthy diet quality, 82 % had a diet that needed improvement, and 3 % had a poor diet quality. This was independent of surgery type and was comparable in the second trimester (p = 0.525). No difference between groups was observed for the PA level, but the PA level in the bypass group significantly decreased from the first to the second trimester (p = 0.033).

CONCLUSIONS

Nutritional advice and lifestyle coaching in this high-risk population seems recommendable since only 15 % of the pregnant women had a healthy diet quality, 25 % was smoking at the beginning of pregnancy, and the reported PA levels were low.

Coxsackievirus B1 peritonitis in a patient treated with continuous ambulatory peritoneal dialysis: a case report and brief review of the literature

We report a case of viral peritonitis caused by coxsackievirus B1 in a 79-year-old male undergoing continuous ambulatory peritoneal dialysis (CAPD), and review the English language literature. Clinicians should be aware of viral peritonitis in patients on CAPD presenting with a viral syndrome and mononuclear peritoneal dialysis effluent. Currently, viral diagnostic tests are available to confirm the diagnosis and avoid unnecessary treatment with antibiotics.

The role of surgery and transplantation in neuroendocrine tumours

Surgery represents the only chance of cure for a patient with a neuroendocrine tumour (NET). The main indications for surgery lie in the risk of developing metastatic disease with increasing tumour diameter and for a functioning NET also in control of the hormonal syndrome. However, only a small minority of patients presents with a potentially resectable primary NET without metastatic disease. An R0-resection is mandatory, which may be achieved in selected cases by tissue sparing surgical techniques. Most patients unfortunately present with a locally advanced or metastatic disease. For patients with an advanced functioning NET, control of the hormonal syndrome may also represent a surgical indication. Various cytoreductive techniques or, in highly selected cases, liver transplantation can be applied. For locally advanced non-functioning tumours, there is an indication for surgery in large tumours which tend to create local complications because of bleeding or bowel obstruction. Especially in ileal NETs aggressive surgical therapy is recommended because of prevention of long-term complications, which may improve survival.

Role of chemotherapy in gastro-entero-pancreatic neuroendocrine tumors: the end of a story?

Gastroenteropancreatic Neuroendocrine Tumours (GEP NET) are heterogeneous and rare malignancies although their prevalence is increasing. Multiple therapeutic approaches are available to date for their management, including surgery, hormonal and immune radionucleide therapies and chemotherapy. The purpose of this review is to collect, examine, and analyze data available regarding contemporary chemotherapeutic management of GEP NET in order to determine whether or not chemotherapy still takes place in the therapeutic arsenal of GEP NET. We therefore performed a systematic search of all the English-spoken literature regarding GEP NET. Anthracyclins, 5-fluorouracil (5-FU), DTIC and streptozotocin are amongst the most commonly used chemotherapeutic agents, usually prescribed in combination. Their efficiency in reducing tumor burden is not always associated with better survival, perhaps due to severe toxicity. Chemotherapy in GEP NET is mainly devoted to poorly differentiated tumours, but also in well differentiated carcinomas either not eligible or resistant to other therapies. Chemotherapy remains therefore useful in specific cases of GEP NET management. However, a new era of antitumoral agents, such as targeted therapies, could eventually replace these old recipes in the near future.

Diagnostic pitfalls in digestive neuroendocrine tumours

Gastro-entero-pancreatic neuroendocrine tumours (GEP NET) represent a rare and highly heterogeneous entity that often is revealed by vague and non-specific symptoms, leading to a delayed diagnosis. Here we will review some of the most regularly observed false positive and false negative cases and provide clues to recognize and manage them properly. Particularly, the value of chromogranin-A as a serum tumour marker and Somatostatin receptor scintigraphy as an imaging test, are reviewed. Indeed, chromogranin-A and other hormones, such as gastrin, as well as urinary 5-hydroxy-indolic acetic acid (5-HIAA) are often tested to diagnose NET without appraising the clinical situation, leading to extensive work-up on false bases. On the other hand, some tests are performed in situations where they do not add additional information (e.g. 5-HIAA in pancreatic or rectal NET) because invariably negative. Somatostatin receptor scintigraphy is an expensive examination, still not reimbursed in Belgium, for which indications must be carefully assessed, knowing its specificity and sensitivity.

Carcinoid heart disease--a hidden complication of neuroendocrine tumours

Carcinoid heart disease (CHD) develops in serotonin-producing neuroendocrine tumours (NET) due to fibrotic endocardial plaques with associated valve dysfunction leading most often to right-sided heart failure. The classical carcinoid syndrome usually occurs when serotonin-producing NET metastasize to the liver. Up to 50% of those patients will exhibit carcinoid heart disease. The pathophysiological process is not yet completely understood: serotonin is considered to be a major initiator of the fibrotic process, but other tumour secreted factors may contribute to the pathogenesis. Histopathology reveals intact valvular cusps with superimposed fibrotic plaques, leading to thickening and retraction of the valves, causing valvular dysfunction. A high index of clinical suspicion to diagnose CHD is needed since symptoms can be rather non-specific. Transthoracic echocardiography is the gold standard for diagnosis and should probably be performed at the time of diagnosing serotonin-producing NET and then repeated annually. On the other hand, when diagnosing right-heart failure, the presence of CHD and underlying serotonin-producing NET should be taken into account. Therapeutic options include pharmacotherapy for heart failure, control of the systemic carcinoid disease and in selected individuals cardiac valve replacement. The elucidation of the pathologic process is necessary to develop targeted antifibrotic therapeutic agents since CHD seems to be irreversible and associated with poor prognosis.

Locoregional and radioisotopic targeted treatment of neuroendocrine tumours

Gastro-entero-pancreatic neuroendocrine tumours (GEP NET) are a heterogeneous group of proliferative disorders whose management dramatically relies on tumour biology. For well-differentiated, low-proliferative index tumours, locoregional treatment and targeted radioisotopic therapies offer an attractive and seemingly efficient alternative to palliative surgical resections. Lack of well-designed, prospective, randomized multicentric studies hinders a balanced evaluation of available locoregional treatment methods: embolization, chemo-embolization, radio-embolization. According to available datas, all techniques achieve a 50-60% radiological response rate and almost 80% of symptomatic relieve for the patients, while their impact on progression-free and overall survival remains not assessable. Same conclusions can be drawn for radiolabeled targeted therapies like MetaiodoBenzylGuanidine (MIBG) and Peptide Receptor Radionuclide Therapy (PRRT), which, provided that their target is expressed by tumour cells, can deliver therapeutic doses of radiation to neoplastic tissues. 131I-MIBG has been associated with a 50% symptomatic response rate and mainly haematological toxicities. PRRT with 111In-DiethyleneTriamineentaacetic Acid-Octreotide, [90Y-DOTA0-Tyr3]-Octreotide, or [177Lu-DOTA0-Tyr3]-Octreotate seem to alleviate symptoms in 50% of patients and obtain a radiological response in 30-38%. Renal toxicity, partially preventable, is more frequent than previously thought and result in an annual decrease in glomerular function by 4 to 8% per year. Forthcoming research in GEP NET should by a majority be designed in randomized, prospective and multicentric fashion. Locoregional disease trials must focus on clinical outcome differences between embolization techniques (embolization, chemoembolization and radioembolization) and surgery. In disseminated disease, studies should assess radiolabeled targeted therapies efficiency when administered along with and compared to new biological and older chemotherapeutic agents.

The potential role of targeted therapies in the management of neuroendocrine tumours

The management of gastro-entero-pancreatic neuroendocrine tumours is evolving thanks to new TNM-classification, diagnostic and staging procedures and new therapeutic options. Targeting new pathways, mostly angiogenesis, development of novel agents is under way and opens new perspectives in controlling the evolution of these tumours and possibly changing their management. In parallel, new functional imaging techniques and biomolecular markers will be developed to provide adequate tools for the assessment of tumor response according to therapeutic intervention on angiogenesis, proliferation and apoptosis. This paper reviews the potential role of new investigational targeted agents which will likely become the backbone of future therapy of neuroendocrine tumors.

The antiproliferative effect of somatostatin analogs: clinical relevance in patients with neuroendocrine gastro-entero-pancreatic tumours

Somatostatin analogs (SSAs) have an important role in the management of patients with neuroendocrine tumours of the gastrointestinal tract and pancreas (GEP NETs). These compounds can control the symptoms induced by the production of hormones and peptides. The antiproliferative effects of SSAs and especially tumour shrinkage are less obvious in patients with GEP NETs than in those with acromegaly. However, based upon phase II experience there is a strong suggestion of a disease stabilizing effect of SSAs in selected patients. Those patients with a progressive, non-functional GEP NET, positive octreotide scintigraphy, a low proliferation index and in the absence of surgical options may benefit from a first-line medical therapy with SSAs. The exploration of the mechanisms of this effect are unclear and hampered by the lack of suitable preclinical models. The better understanding of the tumour biology of GEP NETs, together with the development of new SSAs with better affinity on all somatostatin receptors, represent an unmet medical need.

Quantitation in SPECT using an effective model of the scattering

A new method for correcting simultaneously the attenuation, scatter and resolution effects in SPECT has been developed for the case of a homogeneous medium. It is based on an effective model of the scatter process. This model depends on only four parameters which are determined experimentally and remain independent of the geometry and of the dimensions of the scatter medium. The method uses the data from the peak events and does not need additional energy windows on the scattered events. An original filter is proposed to remove the noise due to the poor statistics of clinical data. Tests on phantoms varying in size and activity show that the model allows absolute activity determination with an accuracy of a few per cent.

Intragastric distribution of a standardized meal in health and functional dyspepsia: correlation with specific symptoms

In functional dyspepsia, abnormal intragastric distribution of a test meal has been identified but has never been correlated to any symptom pattern. The aim of this study was to compare the intragastric distribution of a meal between functional dyspepsia patients and controls, and to correlate distribution with symptom patterns, using scintigraphic gastric emptying studies. In forty patients with functional dyspepsia and 29 healthy volunteers, scintigraphic planar images were obtained immediately after ingestion of a mixed radiolabelled test meal and every 20 min for 2 h. The images of the stomach were divided into proximal and distal compartments. The mean intragastric distribution was similar in patients and controls. Over the whole test, 18 (45%) and 20 (50%) patients had a distal redistribution of the solid and liquid phase of the meal, respectively, while proximal retention of these phases was found in 13 (33%) and 9 (23%) patients. Early satiety was associated with early distal redistribution of the liquid phase and fullness was associated with late proximal retention. This study shows similar intragastric distribution of a test meal in health and functional dyspepsia. Within the patient group, an association between abnormal intragastric distribution patterns and symptom profiles was found, which might be related to different pathophysiological mechanisms.

An unusual metastatic motilin-secreting neuroendocrine tumour with a 20-year survival. Pathological, biochemical and motility features

Motilin-secreting neuroendocrine tumours have been rarely described. Immunohistochemical, biochemical and motility investigations were performed in a 62-year-old man with liver and bone metastases of a motilin-secreting neuroendocrine tumour originating from a rectal polyp removed 14 years previously. Symptoms related to liver metastases were reduced by a right hepatectomy whereas plasma motilin levels were decreased. The patient also underwent two operations for spinal cord decompression and survived 6 more years under medical treatment, mainly octreotide. Immunohistochemistry revealed predominant expression of motilin-containing cells, with rare cells expressing somatostatin and pancreatic polypeptide, and staining for only one panendocrine marker, neurone-specific enolase. A liver tumour extract contained 17.9 microg motilin per gram of tissue, which permitted to isolate and characterize human motilin, which was identical to porcine motilin. Plasma column gel chromatography revealed a main peak corresponding apparently to porcine motilin. The patient had no symptoms of disturbed motility. Gastric emptying and gastroduodenojejunal motility were found within normal limits. The absence of alterations of gut motility was perhaps related to sustained autonomous motilin production. The long evolution of this type of tumour suggests that plasma motilin determination should be added to the investigations for neuroendocrine tumours.

OctreoTher: ongoing early clinical development of a somatostatin-receptor-targeted radionuclide antineoplastic therapy

OctreoTher ((90)Y-DOTA-D-Phe(1)-Tyr(3)-octreotide, a.k.a. (90)Y-SMT 487) consists of a somatostatin peptide analogue (Tyr(3)-octreotide), coupled with a complexing moiety (DOTA), and labeled with a tightly bound beta-emitter (yttrium-90). By targeting somatostatin receptor-positive tumors (as imaged by OctreaScan it may deliver a tumoricidal dose of radiation. Phase I clinical trials, conducted in patients with neuroendocrine tumors, established the safety and tolerability of the dose selected for further study and demonstrated the capacity of OctreoTher to deliver radiation doses to tumors that resulted in significant neuroendocrine tumor shrinkage. Novartis-sponsored phase II studies will soon begin to test the efficacy of OctreoTher in breast and small cell lung cancer. A fixed-dose regimen of 120 mCi/cycle x 3 cycles administered with concomitant amino acid infusion has been chosen for the study. Phase I data and published literature support that this fixed dose regimen will be safely tolerated.

Positron emission tomography with fluorodeoxyglucose for suspected head and neck tumor recurrence in the symptomatic patient

OBJECTIVE

To analyze the impact of positron emission tomography with fluorodeoxyglucose (FDG-PET) in the treatment of patients suspected of having head and neck cancer recurrence.

STUDY DESIGN

Prospective and consecutive inclusion of 44 patients presenting with clinical symptoms suggestive of head and neck tumor recurrence.

METHODS

FDG-PET was compared with combined computed tomography (CT) plus magnetic resonance imaging (MRI) procedures for the differential diagnosis between tumor recurrence and benign post-therapeutic changes. For FDG-PET, the potential additional value of semiquantitative indexes was studied. The impact on patient treatment (i.e., their ability to accurately select patients for panendoscopic exploration) was analyzed retrospectively for both CT+MRI and PET workups.

RESULTS

The diagnostic accuracy was found higher for PET than for combined CT+MRI: sensitivity ranged from 96% to 73%, specificity from 61% to 50%, and accuracy from 81% to 64% for PET and CT+MRI, respectively. The accuracy of FDG-PET was the highest (94%) in patients included more than 12 weeks after the end of therapy. In 15 discordant cases, PET was correct in 11 and CT+MRI in 4. Patient selection for panendoscopic exploration and biopsy was correct in 79% and 50% of patients with FDG-PET and CT+MRI, respectively. Quantification of FDG uptake had no additional value over visual analysis alone, although we found that a SUVlbm (standardized uptake value corrected for lean body mass) threshold of 3 could be helpful in patients scanned less than 12 weeks after the end of therapy.

CONCLUSION

FDG-PET has a major additional diagnostic value to CT+MRI for the evaluation of the symptomatic patient suspected of having head and neck cancer recurrence. PET could have a direct impact on management by correctly selecting patients in whom a panendoscopic exploration with biopsy is indicated.

[Portal hypertension caused by intra-hepatic block during chronic lymphoid leukemia]

Portal hypertension in chronic lymphocytic leukemia is rare. A 66 year-old man was admitted for splenomegaly, thrombopenia and cholestasis. Endoscopy showed esophageal varices. The hepatic venous pressure gradient was 15 mmHg. The liver biopsy showed dense leukemia cells in sinusoidal and portal sites. After splenectomy, the hepatic venous pressure gradient normalized, but esophageal varices and cholestasis persisted. The authors discuss the mechanisms of portal hypertension in chronic lymphocytic leukemia. Previously reported cases are summarized.

The role of radioactive somatostatin and its analogues in the control of tumor growth

Peptide receptor scintigraphy with the radioactive somatostatin analogue [111In-DTPA-D-Phe1]octreotide is a sensitive and specific technique to show in vivo the presence and abundance of somatostatin receptors on various tumors. With this technique primary tumors and metastases of neuroendocrine cancers as well as of many other cancer types can be localized. This technique is currently used to assess the possibility of peptide receptor radionuclide therapy with repeated administration of high doses of [111In-DTPA-D-Phe1]octreotide. 111In emits Auger and conversion electrons, having a tissue penetration of 0.02-10 microns and 200-500 microns, respectively. Thirty end-stage patients with mostly neuroendocrine progressing tumors were treated with [111In-DTPA-D-Phe1]octreotide, up to a maximal cumulative patient dose of about 74 GBq, in a phase-I trial. There were no major clinical side effects after up to 2 years of treatment, except that in a few patients a transient decline in platelet counts and lymphocyte subsets occurred. Promising beneficial effects on clinical symptoms, hormone production, and tumor proliferation were found. Of the 21 patients who received a cumulative dose of more than 20 GBq, eight showed stabilization of disease and six others a reduction in tumor size. There is a tendency towards better results in patients whose tumors have a higher accumulation of the radioligand. Peptide receptor radionuclide therapy is also feasible with 111In as the radionuclide. Theoretically, depending on the homogeneity of distribution of tumor cells expressing peptide receptors and the size of the tumor, beta-emitting radionuclides, e.g., 90Y, labeled to DOTA-chelated peptides may be more effective than 111In for peptide receptor radionuclide therapy. The first peptide receptor radionuclide therapy trials with [90Y-DOTA-Tyr3]octreotide started recently.

Scintigraphy and radionuclide therapy with [indium-111-labelled-diethyl triamine penta-acetic acid-D-Phe1]-octreotide

Peptide receptor scintigraphy with [111In-DTPA-D-Phe1]-octreotide is a sensitive and specific technique to show in vivo the presence and abundance of somatostatin receptors on various tumours. With this technique primary tumours and metastases of neuroendocrine cancers as well as of many other cancer types can be localised. This technique is currently used to assess the possibility of peptide receptor radionuclide therapy with repeated administrations of high doses of [111In-DTPA-D-Phe1]-octreotide. 111In emits Auger and conversion electrons having a tissue penetration of 0.02 to 10 microns and 200 to 500 microns, respectively. Twenty end-stage patients, mostly with neuroendocrine progressing tumours, were treated with [111In-DTPA-D-Phe1]-octreotide, up to a maximal cumulative patient dose of about 74 GBq, in a phase I trial. Results showed there were no major clinical side-effects after up to 2 years treatment, except that in a few patients a transient decline in platelet counts and lymphocyte subsets occurred. Promising beneficial effects on clinical symptoms, hormone production and tumour proliferation were found. Of the 16 patients who received a cumulative dose of more than 20 GBq, 5 patients showed stabilisation of disease and 5 other patients a reduction in size of tumours. There is a tendency towards better results in patients whose tumours have a higher accumulation of the radioligand. In conclusion, peptide receptor radionuclide therapy is feasible, also with 111In as radionuclide. Theoretically, depending on the homogeneity of distribution of tumour cells expressing peptide receptors, beta-emitting radionuclides, e.g. 90Y, labelled to DOTA-chelated peptides may be more effective than 111In for peptide receptor radionuclide therapy. The first peptide receptor radionuclide therapy trials with [90Y-DOTA-Tyr3]-octreotide started recently.

Dietary restriction of energy and sugar results in a reduction in human cytochrome P450 2E1 activity

Dietary habits are often considered as a pathogenic factor for fatty liver. The impact of dietary intake and steatosis on drug metabolism remains poorly investigated. Our aim was to assess the effect of dietary intake on in vivo cytochrome P450 (CYP) activities in eleven patients with abnormal liver function tests potentially due to fatty liver and associated with a high-sugar diet. Liver function tests, liver volume, aminopyrine breath test (ABT) and chlorzoxazone (CZ) pharmacokinetics (area under the curve, AUC) which are known to reflect CYP2E1 activity were evaluated before and after 2 months restriction of dietary sugar intake. Features at inclusion were an increased BMI (30.3 (SD 3.2) kg/m2), high hepatic volume (1.96 (SD 0.48) litres), hyperechogenic liver parenchyma, elevated liver enzyme activities (alanine aminotransferase (EC 2.6.1.2) 58.6 (SD 17.4) IU/1 with alanine aminotransferase: aspartate aminotransferase (EC 2.6.1.1) ratio > 1), together with a normal ABT value (0.68 (SD 0.21)% specific activity of administered dose of [14C]aminopyrine in breath after 1 h) and a high CYP2E1 activity (CZ AUC 20.3 (SD 7.1) micrograms/ml per h). A dietary sugar restriction was prescribed. On the basis of repeated interviews by the same dietitian, unaware of any clinical and biochemical data, six patients remained complaint to the diet and exhibited reductions in BMI (P < 0.001), serum alanine aminotransferase (P = 0.008), liver volume (P = 0.002) and CYP2E1 activity (P = 0.007), a significant increase in ABT (P < 0.001) together with the disappearance of liver hyperechogenicity at ultrasound. In contrast, the five non-compliant patients did not show any significant change in any of these variables. In conclusion, CYP2E1 activity is induced in patients with perturbations of liver function tests potentially due to fatty liver. In these patients, effective dietary sugar restriction is associated with a reduction in liver volume, a reduction in CYP2E1 activity and an increased aminopyrine metabolism rate.

Radiolabelled somatostatin analogue(s) for peptide receptor scintigraphy and radionuclide therapy

BACKGROUND

Peptide receptor scintigraphy with the radioactive somatostatin analogue, [111In-DTPA0]octreotide, is a sensitive and specific technique to show in vivo the presence and abundance of somatostatin receptors on various tumours.

AIM

With this technique primary tumours and metastases of neuroendocrine cancers as well as of many other cancer-types can be localised. This technique is currently used to assess the possibility of peptide receptor radionuclide therapy (PRRT) with repeated administrations of high doses of [111In-DTPA0)octreotide. 111In emits Auger and conversion electrons having a tissue penetration of 0.02-10 microns and 200 to 500 microns, respectively.

PATIENTS AND METHODS

Thirty end-stage patients with mostly neuroendocrine progressing tumours were treated with [111In-DTPA0]octreotide, up to a maximal cumulative patient dose of about 74 GBq, in a phase I trial.

RESULTS

There were no major clinical side effects after up to two years treatment, except that in a few patients a transient decline in platelets counts and lymphocyte subsets occurred. Promising beneficial effects on clinical symptoms, hormone production and tumour proliferation were found. Of the 21 patients who received a cumulative dose of more than 20 GBq, eight patients showed stabilisation of disease and six other patients a reduction in size of tumours. There is a tendency towards better results in patients whose tumours have a higher accumulation of the radioligand.

CONCLUSIONS

PRRT is feasible, also with 111In as radionuclide. Depending on the homogeneity of distribution of tumour cells expressing peptide receptors and the size of the tumour, beta-emitting radionuclides, e.g., 90Y, labelled to DOTA-chelated peptides, are also attractive candidates for PRRT. The first PRRT trials with [90Y-DOTA0,Tyr3]octreotide started recently.

[Current data and perspectives on positron emission tomography oncology-radiotherapy]

Positron emission tomography (PET) is one of the most promising diagnostic procedures in oncology. Using the glucose analogue fluorodeoxyglucose, PET produces whole-body images and is highly sensitive for tumor diagnosis and staging. We review three particular clinical situations in which PET-FDG has proven not only its diagnostic accuracy, but also its impact on patient management, i.e., the staging of non-small cell lung cancer, diagnosis and staging of colo-rectal cancer and head and neck cancer recurrence. Image registration yields anatomo-metabolic images that could be used as additional information for the determination of radiation fields. Tracer and technical issues remain to be solved before PET can be routinely used for that purpose.

Attenuation correction in whole-body FDG oncological studies: the role of statistical reconstruction

Whole-body fluorine-18 fluoro-2-d-deoxyglucose positron emission tomography (FDG-PET) is widely used in clinical centres for diagnosis, staging and therapy monitoring in oncology. Images are usually not corrected for attenuation since filtered backprojection (FBP) reconstruction methods require a 10 to 15-min transmission scan per bed position on most current PET devices equipped with germanium-68 rod transmission sources. Such an acquisition protocol would increase the total scanning time beyond acceptable limits. The aim of this work is to validate the use of iterative reconstruction methods, on both transmission and emission scans, in order to obtain a fully corrected whole-body study within a reasonable scanning time of 60 min. Five minute emission and 3-min transmission scans are acquired at each of the seven bed positions. The transmission data are reconstructed with OSEM (ordered subsets expectation maximization) and the last iteration is reprojected to obtain consistent attenuation correction factors (ACFs). The emission image is then also reconstructed with OSEM, using the emission scan corrected for normalization, scatter and decay together with the set of consistent ACFs as inputs. The total processing time is about 35 min, which is acceptable in a clinical environment. The image quality, readability and accuracy of uptake quantification were assessed in 38 patients scanned for various malignancies. The sensitivity for tumour detection was the same for the non-attenuation-corrected (NAC-FBP) and the attenuation-corrected (AC-OSEM) images. The AC-OSEM images were less noisy and easier to interpret. The interobserver reproducibility was significantly increased when compared with non-corrected images (96.1% vs 81.1%, P<0.01). Standardized uptake values (SUVs) measured on images reconstructed with OSEM (AC-OSEM) and filtered backprojection (AC-FBP) were similar in all body regions except in the pelvic area, where SUVs were higher on AC-FBP images (mean increase 7.74%, P<0. 01). Our results show that, when statistical reconstruction is applied to both transmission and emission data, high quality quantitative whole-body images are obtained within a reasonable scanning (60 min) and processing time, making it applicable in clinical practice.

Can dual-headed 18F-FDG SPET imaging reliably supersede PET in clinical oncology? A comparative study in lung and gastrointestinal tract cancer

In this study, we prospectively compared the sensitivity of PET and planar SPET (collimated gamma camera) 18F-FDG imaging in patients with lung and gastrointestinal tract cancer and analysed their respective impact on patient management. Twenty-eight patients with lung cancer and 14 with gastro-intestinal tract tumours were scanned on the same day with a PET and a collimated planar SPET gamma camera. The planar SPET procedure consisted of whole-body planar views and a tomographic acquisition centred over the torso or the abdomen, with the total imaging time within the same range as the whole-body PET procedure. The staging of lung cancer patients was accurate in 86% with PET and 64% with planar SPET. Planar SPET would have led to inappropriate therapeutic decisions in 8 of 28 patients, mainly due to undetected distant metastases. In patients with suspected gastrointestinal tract cancer, planar SPET identified 7 of 15 (47%) proven tumour sites, whereas PET identified 14 of 15 (93%). Our results suggest that collimated planar SPET cameras are not a substitute for dedicated PET scanners. The sensitivity for the detection of tumours is unacceptably low and can impair patient management. The use of multiple tomographic acquisitions could improve the sensitivity but would require a longer scanning time.

Uptake of In-111 pentetreotide by pleural plaques

Somatostatin receptor imaging with In-111 pentetreotide has been validated for the diagnosis and staging of chest tumors with neuroendocrine differentiation such as bronchial carcinoid and small cell lung cancer. In-111 pentetreotide uptake is not specific for neuroendocrine tumors because somatostatin receptors are also expressed by white blood cells, leading to the in vivo visualization sites of infection sites or active inflammation. Pleural plaques may be due to asbestos exposure or tuberculosis. Presented here are three cases of In-111 pentetreotide uptake in pleural plaques. This uptake by benign lesions may be misleading in the diagnostic work-up of patients with lung tumors.

Inadequate detection of accessory spleens and splenosis with laparoscopic splenectomy. A shortcoming of the laparoscopic approach in hematologic diseases

BACKGROUND

The ultimate goal of surgery for hematological disorders is the complete removal of both the spleen and accessory spleens in order to avoid recurrence of the disease. Whereas splenectomy by open surgery provides excellent results, the validity of laparoscopic splenectomy in this regard remains unknown.

OBJECTIVE

The purpose of this study was to evaluate the detection of accessory spleens during laparoscopic splenectomy for hematologic diseases.

METHODS

We therefore evaluated the pre-, intra-, and postoperative detection of accessory spleens in a consecutive series of 18 patients treated by elective laparoscopic splenectomy for hematological diseases by using computed tomography (CT) and denatured red blood cell scintigraphy (DRBCS).

RESULTS

Preoperative CT, DRBCS, and laparoscopic exploration detected 25%, 25%, and 75% of accessory spleens, respectively. At time of laparoscopy, 16 accessory spleens were detected in seven of the 18 patients (41%). In two patients (11%), laparoscopic exploration failed to detect accessory spleens, whereas preoperative CT (one case) and DRBCS (one case) did reveal them. Postoperatively, during a mean follow-up of 28 months (median, 24; range, 12-44 months), nine patients (50%) showed persistence of splenic tissue by DRBCS, and three of them had signs of disease recurrence.

CONCLUSIONS

This prospective clinical study suggests that elective laparoscopic surgery for hematological diseases does not allow complete detection of accessory spleens. Moreover, after such a laparoscopic approach, residual splenic tissue is detectable in half of the patients during the follow-up.

14C-Propoxyphene demethylation in the rat. An example of differences between liver and intestinal drug-presystemic metabolism

Presystemic metabolism is believed to occur mainly in the liver with some minor intestinal participation. The aim of this study was to investigate the respective part of each of these two organs in the metabolism of the analgesic d-propoxyphene (DP). Pharmacological doses of DP were given in the duodenum (ID), the portal vein (IP), and the femoral vein (IV) of male Wistar rats. A tracer dose of 14C-DP was also administered either in IV, IP, or ID as well as in hepatectomized rats or rats with bile duct diversion. In vitro demethylation occurring in liver and intestinal microsomes was also studied. Absolute DP bioavailability obtained after oral administration was two times higher than that observed after portal administration (48.9% vs. 23.2%, respectively), an result opposite (i.e. a lower bioavailability) of that expected on the basis of the existence of a liver enzyme saturation phenomenon. The 14CO2 cumulative excretion after 14C-DP administration was significantly lower after IV or ID administration than after injection in the portal vein as a bolus or within 20 min. The biliary excretion of the labeled compound varied in the opposite direction, being greater after IV or ID than after IP administration, suggesting that the metabolism of DP in the liver is influenced by an extrahepatic transformation. This most likely occurs in the gut since the production of 14CO2 after IV administration was similar to that after ID administration. This transformation did not prohibit DP detection in the systemic blood but was sufficient to increase the part eliminated with bile and to decrease the part demethylated into NP. Demethylation mainly occurs in the liver since the production of 14CO2 was nearly abolished in hepatectomized rats. Furthermore, microsomes of hepatic but not of intestinal origin were able to demethylate DP. Our data suggest that the transformation of DP occurring in gut after oral administration is responsible for changes in the hepatic metabolism of the drug.

Ferumoxides and Tc-99m sulfur colloid: comparison of the tumor-to-liver uptake in focal nodular hyperplasia

The tumor-to-liver uptake of two reticuloendothelial agents, namely ferumoxides and technetium-99m (Tc-99m) sulfur colloid, was compared in focal nodular hyperplasia (FNH). Twelve patients with FNH who had undergone ferumoxides-enhanced MR imaging and planar Tc-99m sulfur colloid scintigraphy within 1 year were included from the study. Fourteen patients with FNH with a diameter larger than 3 cm were selected for the comparison. The tumor-to-liver ferumoxides uptake was calculated and the Tc-99m sulfur colloid uptake was assessed visually. Fermuoxides uptake was observed in all but one patient with FNH (mean tumor-to-liver ratio = .36). The six tumors showing normal (n = 5) or increased (n = 1) radiocolloid uptake when compared to the liver accumulated more ferumoxides than the eight tumors showing decreased radiocolloid uptake (P < .01). However, in some tumors, no direct relation was observed between ferumoxides and Tc-99m sulfur colloid uptake. Our observations suggest that ferumoxides uptake might not exactly mimic Tc-99m sulfur colloid uptake in FNH.

A non-negative fast multiplicative algorithm in 3D scatter-compensated SPET reconstruction

Single-photon emission tomographic (SPET) reconstruction can be improved, especially for noisy images, by using the iterative expectation-maximization of the maximum-likelihood (EM-ML) algorithm. Its application to clinical routine is, however, hampered by the high number of iterations necessary to achieve acceptable results. Therefore various methods have been developed to accelerate the EM-ML algorithm. In this paper a new accelerated EM-ML-like multiplicative algorithm is proposed for SPET reconstruction. Contrary to some other accelerating methods, it preserves two of the most important properties of the EM-ML, namely pixel positivity inside the patient body and null activity outside. The convergence speed is improved by a factor which can reach 100 in high spatial frequency or low count regions. Good estimates in the low count region are obtained without any smoothing, even at typical routine clinical count rates. The algorithm used in conjunction with the 3D effective one scatter path model provides high-quality SPET images and accurate quantitation.

Radiographic skeletal survey and radionuclide bone scan in Langerhans cell histiocytosis of bone

BACKGROUND

The lack of a consensus in the literature on the imaging strategy in Langerhans cell histiocytosis (LCH) bone lesions in childhood.

OBJECTIVE

To evaluate the relative value of radionuclide bone scan (RBS) and radiographic skeletal survey (RSS) in the detection of LCH bone lesions, both in the initial work-up of the disease and during the follow-up period.

MATERIALS AND METHODS

Ten children with bone lesions evaluated by means of RSS and RBS in a retrospective study (1984-1993).

RESULTS

Fifty radiologically and/or scintigraphically abnormal foci were detected: 27 anomalies in the initial work-up (12 by both RSS and RBS, 8 by RSS only and 7 by RBS only) and 23 additional anomalies during follow-up (10 by both RSS and RBS, 10 by RSS only and 3 by RBS only). RSS+/RBS- lesions (n = 18) are more frequently encountered in the skull (P = 0.038), and more frequently lack radiologic signs of osteoblastic activity (P = 0.020), than RSS+/RBS+ lesions (n = 22). RSS-/ RBS+ abnormalities (n = 10) were most frequently insignificant.

CONCLUSION

In the initial work-up both RSS and RBS should be carried out, while in the follow-up only RSS should be performed.

Indium-111-pentetreotide uptake in endocrine tumors and lymphoma

The biodistribution of 111In-pentetreotide was assessed in patients with gastroenteropancreatic (GEP) neuroendocrine tumors or lymphoma and in control patients and analyzed as a function of scanning time, presence or absence of tumor uptake, tumor type and previous octreotide treatment.

METHODS

Patients underwent imaging 4 and 24 hr after injection of approximately 200 MBq 111In-pentetreotide. The frequency of organ visualization was assessed on planar views. Total organ and tumor uptake (% injected dose [ID]) was determined using the geometric mean method and regional tissue uptake (% ID/100 ml) by semiquantitative SPECT.

RESULTS

Liver, spleen, kidneys and urinary bladder were visualized in all patients. Thyroid, bowel and pituitary were more often visualized at 24 hr than at 4 hr. Activity in the gallbladder, breast, ureters and ascites was only occasionally observed. Total liver, spleen and thyroid uptake was stable over time, whereas kidney activity decreased slightly. At 24 hr, regional uptake was threefold lower in the liver than in the spleen or kidneys and was similar in the three groups. In patients with long-term octreotide therapy, a positive correlation was found between the duration of octreotide therapy and liver or spleen uptake. Total and regional tumor uptake showed high intraindividual and interindividual variations. Total tumor activity was stable over 24 hr in patients with GEP and decreased in those with lymphoma. The mean regional tumor uptake was 10-fold lower in patients with lymphoma than in those with GEP. Cold octreotide injected 24 hr after tracer administration did not result in any displacement of organ and tumor activity.

CONCLUSION

Organ uptake seems not to be influenced by the presence of 111In-pentetreotide-positive lesions or by tumor type. Tumor uptake is highly variable among patients and clearly lower in patients with lymphoma than in those with GEP. The widespread of uptake values in tumors indicates that radiotherapy using radiolabeled somatostatin analogs may not be applicable to all patients with 111In-pentetreotide-positive tumors.

Increased uptake of indium-111 pentetreotide up to 10 years after external thoracic irradiation: report of two cases

Indium-111 pentetreotide scintigraphy was performed in two patients for the localization of recurrent medullary thyroid carcinoma treated by surgery and external radiotherapy 1 and 10 years earlier. A marked uptake of the radiopharmaceutical was demonstrated in the lung areas that had been irradiated. These cases strongly suggest that this uptake is related to pulmonary fibrosis, a well-known complication of radiotherapy, even long after the irradiation. Therefore, attention must be paid to the avoidance of false-positive interpretation of somatostatin receptor scintigraphy in patients previously treated by radiotherapy.

Somatostatin receptor: scintigraphy and radionuclide therapy

Peptide receptor scintigraphy is more sensitive at the biological than anatomical level, in contrast to conventional imaging, which it complements. Neuroendocrine tumours have the most somatostatin receptors in vitro and their metastases are somatostatin receptor positive in vitro, so that [111In-DTPA-D-Phe1]octreotide (OCT) can be used to image them. OCT was compared with conventional imaging techniques (CON) in a European Multicentre Trial. In 350 evaluable patients, CON detected 88%, and OCT 80% (glucagonomas 100%, VIPomas 88%, carcinoids 87%, non-functioning islet cell tumours 82%, insulinomas 46%) of tumour sites but there was no systematic use of abdominal single-photon-emission computerised tomography. OCT demonstrated multiple tumour sites in 62 of 178 patients in whom CON had found only 1 lesion, with 60% confirmed. 12/16 lesions detected by OCT in 11 patients with no lesions according to CON were also confirmed. The impact of OCT on management was evaluated in 235 patients and affected 40%: it determined 29 surgical decisions, led to octreotide therapy in 47, and modified octreotide dose in 18. Six end-stage patients with neuroendocrine tumours were treated with OCT radionuclide therapy (up to a cumulative dose of 53 GBq per patient) in a phase I trial. There were no major side-effects after up to 2 years treatment, with impressive effects on hormone production and a likely anti-proliferative effect.

Microsomal function in hepatitis B surface antigen healthy carriers: assessment of cytochrome P450 1A2 activity by the 14C-caffeine breath test

The hepatitis B surface antigen (HBsAg) carrier state is associated with changes in hepatocellular function involving the cytochrome P450 (CYP) system. Among this system, CYP1A2 enzyme plays an important role in chemical carcinogenesis and in the metabolism of several drugs. We have thus investigated CYP1A2 function using two 14C-caffeine breath tests (3-methyl-14C; C3BT and 7-methyl-14C caffeine; C7BT) in 12 HBsAg healthy carriers and 8 healthy volunteers matched for 14C-aminopyrine breath test values. HBsAg carriers exhibited lower C3- and C7BT values than normal controls. This difference, however, did not reach statistical significance except for C7BT values normalised for aminopyrine breath test values. Our data thus do not support the association between viral presence and CYP1A2 dysfunction.

Somatostatin receptor imaging with indium-111-pentetreotide in gastroenteropancreatic neuroendocrine tumors: safety, efficacy and impact on patient management

Indium-111-pentetreotide, a radiolabeled somatostatin analog, has been proposed for imaging tumors bearing somatostatin receptors. This study evaluates the safety, efficacy and impact on patient management of this scintigraphic agent in patients with gastroenteropancreatic (GEP) neuroendocrine tumors.

METHODS

We studied 47 consecutive patients with a proven or clinically suspected GEP neuroendocrine tumor who were imaged 4 and 24 hr after injection of 111In-pentetreotide. The patients were monitored for adverse reactions and changes in vital signs or clinical chemistry over 24 hr. The scintigraphic findings were compared with results from conventional imaging methods. The patients were followed over a minimal 6-mo period during which further localization procedures were performed to confirm or refute the additional tumor sites found at scintigraphy.

RESULTS

No adverse reactions or clinically relevant changes in clinical chemistry were noted after injection of the radiopharmaceutical. The final diagnosis of a GEP neuroendocrine tumor was retained in 38 patients. Somatostatin receptor-positive lesions were found in 33 of these patients, whereas conventional methods were positive in 31 patients. Of the 54 sites seen by conventional procedures, 50 sites were also detected scintigraphically.

CONCLUSION

Indium-111-pentetreotide is a safe, sensitive imaging agent in the detection of GEP neuroendocrine tumor sites. Indium-111-pentetreotide also provides information on the somatostatin receptor status of the tumor and may therefore aid in therapeutic decisions.

Human neutrophil and plasma endopeptidase 24.11: quantification and respective roles in atrial natriuretic peptide hydrolysis

Neutral endopeptidase 24.11 activities were quantified on human peripheral blood cell preparations (reflecting the enzyme concentration on the surface of neutrophils) and in the corresponding diluted plasmas by a spectrofluorimetric assay. Despite statistically identical values in both compartments, enzymatic activity towards atrial natriuretic peptide was not comparable. Indeed, incubation of the radiolabelled peptide in whole blood resulted in the thiorphan-sensitive production of the labelled metabolites Phe-Arg-Tyr and the Cys-Phe bond-cleaved peptide. A similar degradation pattern was observed for blood cells but not for plasma, providing evidence for the exclusive involvement of neutrophil endopeptidase in this peptide inactivation. In search for plasma component(s) susceptible to inhibit enzymatic activity, we observed that in the presence of alpha 2-macroglobulin at the physiological concentration of 3.5 mg mL-1, endopeptidase activity decreased from 100% to 51.2 +/- 8.9% (P = 0.002). Our data suggest that this protein could play a role in the endogenous inhibition of plasma endopeptidase activity.

Hepatobiliary scintigraphy in a patient with bilhemia

A 4-year-old child referred for acute jaundice following percutaneous needle biopsy of the liver underwent hepatobiliary scintigraphy. Although all conventional liver tests suggested preservation of hepatocyte function, the tracer uptake in the liver appeared dramatically reduced at scintigraphy and the blood pool activity did not decrease significantly until the end of the study. Visualization of the bile ducts indicated, however, that the tracer was taken up by the hepatocyte and further excreted into the biliary tree. There was no tracer pooling in the biliary tree although no bowel activity was observed, even on delayed images. The association of persistent blood pool activity, bile duct visualization without tracer pooling, and nonvisualization of the bowel was caused by a continuous recirculation of the tracer from the biliary tree into the bloodstream. The presence of a biliovenous fistula was further proven by percutaneous transhepatic cholangiography performed 24 h later. Since 1975, only 16 cases of bilhemia have been reported. To the best of our knowledge the scintigraphic pattern of this rare but life-threatening complication has not previously been reported.

Brain tumor imaging with PET and 2-[carbon-11]thymidine

METHODS

To assess the potential of thymidine for imaging brain tumors, 20 patients with untreated (n = 14) and recurrent (n = 6) supratentorial intracranial tumors were studied with PET by using 2-[11C]thymidine (Tdr), and the results were compared with [18F]fluorodeoxyglucose (FDG) PET data.

RESULTS

Blood analysis consistently revealed a rapid clearance of the intact Tdr together with the appearance of CO2/HCO3- that, with time, accounted for approximately 70% of the total blood activity. As soon as 10 min after tracer injection, brain images showed a low and homogeneous Tdr distribution over the normal brain structures (cortex-to-blood ratio approximately 1). Visual and quantitative analysis revealed increased Tdr uptake (tumor-to-cortex ratio > or = 1.2) in 11 of 14 untreated tumors and in 5 of 6 recurrent tumors. No correlation was found between Tdr uptake and tumor grade. In 12 of the 14 untreated tumors, FDG uptake was low (tumor-to-cortex ratio: 0.83 +/- 0.79), but a FDG hot spot was visualized in 8 of 10 high-grade and in none of the 4 low-grade tumors. FDG uptake was consistently low in recurrent tumors (tumor-to-cortex ratio: 0.49 +/- 0.19), and PET-FDG was negative in 3 of the 6 cases.

CONCLUSION

These data indicate the feasibility of brain tumor imaging with Tdr and suggest the potential clinical usefulness of the method in the detection of tumor recurrences. The specificity of the method remains, however, to be investigated.