INITIATION OF PATIENTS ONTO LONG-ACTING SOMATOSTATIN ANALOGUE THERAPY FOR NEUROENDOCRINE TUMORS: A SINGLE-CENTER REVIEW OF PRACTICE.

OBJECTIVE: Neuroendocrine tumors (NETs) are being seen increasingly frequently, and recent data show that long-acting somatostatin analogues have become a major initial treatment, regardless of whether the tumors are functioning or not. However, test dosing with subcutaneous (sc) octreotide is usually advised to assess longer-term tolerability, although this advice is mainly based on results with functioning tumors. The aim of the study was to assess the value of an initiating test dose of sc octreotide on the prediction of subsequent adverse events after treatment with the long-acting analogue. METHODS: In a single, large Centre of Excellence for NETs, a first cohort of patients (n = 24) was admitted overnight after an sc injection of octreotide, and then administered the analogue; a subsequent group (n = 53) had the test dose performed on an outpatient basis. Side effects were recorded after the test dose and subsequent treatment with the long-acting analogue. RESULTS: The test dose injection was of little value in predicting adverse events following the long-acting somatostatin analogue. CONCLUSION: Unless there are serious symptoms associated with a functioning NET, it is unnecessary to carry out a test dose; a change to this procedure will improve resource allocation and should enhance early initiation onto maintenance therapy. ABBREVIATIONS: CLARINET = Controlled study of lanreotide antiproliferative response in neuroendocrine tumors LAR = long-acting repeatable NET = neuroendocrine tumor PROMID = Placebo-controlled, double-blind, prospective, randomized study on the effect of octreotide LAR in the control of tumor growth in patients with meta-static neuroendocrine midgut tumors.

Random 'spot' urinary metanephrines compared with 24-h-urinary and plasma results in phaeochromocytomas and paragangliomas.

BACKGROUND: In patients with phaeochromocytomas or paragangliomas (PPGLs), 24-h urine collections for metanephrines (uMNs) are cumbersome. OBJECTIVE: To evaluate the diagnostic utility of ratios to creatinine of 'spot' uMNs. METHODS: Concentrations of uMNs and plasma metanephrines (pMNs) were measured by HPLC-mass-spectrometry. We retrospectively compared correlations of 24-h-urine output and ratio to creatinine in historical specimens and prospectively assessed 24-h and contemporaneous spot urines and, where possible, pMNs. Using trimmed log-transformed values, we derived reference intervals based on age and sex for spot urines. We used multiples of upper limit of normal (ULNs) to compare areas under curves (AUCs) for receiver-operator characteristic curves of individual, and sum and product of, components. RESULTS: In 3143 24-h-urine specimens on 2416 patients, the correlation coefficients between the ratios and outputs of metanephrine, normetanephrine and 3-methoxytyramine in 24-h urines were 0.983, 0.905 and 0.875, respectively. In 96 patients, the correlations between plasma concentrations, urine output and ratios in spot specimens were similar to those for raw output or ratios in 24-h specimens. Of the 160 patients with PPGLs, the CIs for AUCs for individual metabolites overlapped for all four types of measurement, as did those for the sum of the multiple ULNs although these were slightly higher (AUC for spot urine: 0.838 (0.529-1), plasma: 0.929 (0.874-0.984) and output: 0.858 (0.764-0.952)). CONCLUSIONS: Ratios of fractionated metanephrines to creatinine in spot urine samples appear to have a similar diagnostic power to other measurements. The ease of spot urine collection may facilitate diagnosis and follow-up of PPGLs through improved patient compliance.

Measurement of urinary 5-HIAA: correlation between spot versus 24-h urine collection.

BACKGROUND: The 24-h urinary output of 5-hydroxyindoleacetic acid (5-HIAA) is used to monitor disease progression and treatment responses of neuroendocrine neoplasms (NENs). Several conditions are required for 5-HIAA assay, involving urine collection/preservation and food/drug restrictions. AIM: To evaluate the correlation between 5-HIAA concentration in a spot urine sample and the output in a 24-h urine collection, and whether spot urine specimens can replace 24-h collection. METHODS: Patients with NENs or symptoms suggestive of NENs were asked to provide a separate spot urine at the end of the 24-h urine collection for 5-HIAA assessment. The upper reference limit for 24-h urinary 5-HIAA was 40 µmol/24 h. 5-HIAA measurements in spot urine samples were corrected for variation in urine flow rate by expressing results as a ratio to creatinine concentration. RESULTS: We included 136 paired urinary samples for 5-HIAA assessment from 111 patients (100 NENs). The correlation between 5-HIAA values measured in 24-h and spot urines was r = +0.863 (P < 0.001) and r = +0.840 (P < 0.001) including only NEN patients. Using the 24-h urinary 5-HIAA as reference method, the AUC on ROC analysis for spot urinary 5-HIAA was 0.948 (95% CI, 0.914-0.983; P < 0.001), attaining a sensitivity of 83% and specificity of 95% using 5.3 mol/mmol as cut-off for the spot urine. The AUC among NEN patients alone was 0.945 (95% CI, 0.904-0.987; P < 0.001). CONCLUSIONS: The ratio of 5-HIAA to creatinine in a spot urine could replace the measurement of 5-HIAA output in a 24-h urine collection, especially for follow-up of patients with known elevated 5-HIAA levels.