Reproducibility of FDG PET based metabolic tumor volume measurements and of their FDG distribution within.

AIM: The aim of this study was to report on the reproducibility of F-18-fluorodeoxyglucose (FDG) PET MTV (metabolic tumor volume) 40% and MTV2.5, as well as on the intratumor reproducibility in patients, predominantly suffering from lung cancer and squamous cell carcinoma of the head and neck (SCCHN). METHODS: Nineteen patients (14 men) who underwent a baseline staging FDG PET-CT examination and a second radiotherapy treatment planning FDG PET-CT examination prior to treatment initiation within 17 days (range: 7-37 days) from each other were included. Bland-Altman analysis was performed on MTV40% and MTVSUV2.5 values obtained of the primary tumor. For voxelwise comparison of the FDG distribution within tumors the transformation matrices, defined on the CT images, were applied to the corresponding FDG images. Accordingly, the MTV40% of the primary tumor volume was defined and copied on the second FDG image. The coordinates and SUV values of each pixel in the corresponding volumes in both FDG images were used for paired comparison. RESULTS: The standard deviation of the percentage spread around the means of both measurements was respectively 32.5% for MTVSUV2.5 versus 18.8% for MTV40%. Using a cut-off value of 1.96 SD, differences exceeding 64% in MTVSUV2.5 and 37% in MTV40% may be considered to be clinically relevant. Correlation coefficients derived from the voxelwise paired comparison of SUV values within MTV40% volumes delineated on scan 1 and scan 2 ranged from 0.67 to 0.96 (mean: 0.83). Bland-Altman plots demonstrated a low reproducibility for low SUV values and a high(er) reproducibility for high SUV values (inverted triangular shape) in all tumor volumes under study. CONCLUSION: The reproducibility of MTV40% proved better than that of MTVSUV2.5 with a cut-off of 37% (increase or decrease) in MTV allowing to define clinically significant changes. Furthermore, intratumoral voxelwise FDG distribution did not change significantly in most of the patients during the time interval studied.

CA 15.3 measurements for separating FDG PET/CT positive from negative findings in breast carcinoma recurrence. Factors influencing the area under the ROC curve.

UNLABELLED: In breast cancer CA 15.3 is considered the tumour marker of choice. CA 15.3 is directly related to the disease extent and to hormone status (estrogen receptor ER+/ ER-, progesterone receptor PR+/PR-). This study was designed to assess the impact of disease extent, hormone receptor and HER2-status, and circulating blood volume on the area-under the ROC-curve of CA 15.3 to separate FDG PET positive from negative findings. PATIENTS, METHODS: We retrospectively evaluated 379 FDG PET/CT examinations performed in 80 patients with breast cancer. Blood volumes were derived using the formulas by Nadler and multiplied by their corresponding CA 15.3 measurement. RESULTS: ROC-curve analysis revealed an AUC of 0.695 (p = 0.0001) for CA 15.3 to separate FDG PET positive from negative findings. AUC measurements to separate normal scan findings from loco-regional disease and metastatic disease were 0.527 (p = 0.587) and 0.732 (p = 0.0001), respectively. AUC measurements for CA 15.3 to separate positive from negative FDG PET findings, in ER+ and ER- patients, were respectively 0.772 (p = 0.0001) and 0.596 (p = 0.143). AUC measurements for CA 15.3 to separate positive from negative FDG PET findings, in PR+ and PR- patients, were respectively 0.675 (p = 0.0001) and 0.694 (p = 0.0001). In HER2-positive and -negative patients, the AUC measurements were respectively 0.594 (p = 0.178) and 0.701 (p = 0.0001) to separate positive from negative FDG PET findings. CONCLUSION: The AUC for CA 15.3 measurements to separate FDG PET positive from negative findings in breast cancer patients with suspected recurrence proved to be directly related to the extent of the recurrent disease and hormone receptor status and inversely related to HER2-status. Correcting CA 15.3 measurements for blood volumes did not impact the AUC.

Peritumoral indoleamine 2,3-dioxygenase expression in melanoma: an early marker of resistance to immune control?

BACKGROUND: Indoleamine 2,3-dioxygenase (IDO) is an emerging immunomodulating factor in cancer. IDO expression in tumour-negative sentinel lymph nodes (SLNs) of patients with melanoma has a negative prognostic value. OBJECTIVES: To analyse the expression pattern of IDO and associated immunological changes in corresponding primary melanomas (PMs), SLNs and metastases. METHODS: In 120 patients with melanoma, PMs with corresponding SLNs (n = 85) and metastases (n = 18) were analysed by immunohistochemical staining for IDO and FoxP3. Tumour-infiltrating lymphocytes (TILs) were scored. IDO expression in stimulated peripheral blood mononuclear cells (PBMCs) was analysed in 27 patients. RESULTS: IDO expression in the sentinel node strongly correlated with endothelial IDO expression in the peritumoral stroma of the corresponding primary (P < 0·001) and metastatic melanoma (P < 0·05). Sentinel IDO positivity was inversely correlated with CD8+ lymphocytes (P = 0·01) and TILs (P = 0·05) in PM. Both IDO expression in the sentinel (P < 0·01) and the PM (P = 0·04) had a negative prognostic effect on overall survival, independent of Breslow thickness, sex, age, ulceration and sentinel invasion. IDO expression by PBMCs after stimulation with cytotoxic T-lymphocyte antigen 4 was not correlated with sentinel IDO expression but tended to correlate with disease stage (P = 0·04). CONCLUSIONS: Endothelial IDO expression is highly consistent in primary, sentinel and metastatic tissues of patients with melanoma, indicating that immune suppression in melanoma is determined very early in the disease course. This supports that IDO expression in melanoma is a marker of antitumour immune response with an independent prognostic value.

Sunitinib for metastatic renal cell cancer patients: observational study highlighting the risk of important drug-drug interactions.

WHAT IS KNOWN AND OBJECTIVE: Sunitinib, a CYP3A4 substrate, is standard of care treatment in metastatic renal cell carcinoma (mRCC) and is administered orally as a single dose of 50 mg, in a 4 weeks on/2 weeks off regimen. Frequently, dose reduction is necessary because of toxicity, as is the association of comedication to treat side effects. In addition, existing comorbidities in these patients necessitate the intake of various classes of chronic medication. Only limited data are available on the risk of drug-drug interactions (DDI). The objective of our paper was to evaluate prescribed dose, comedication, risk of drug-drug interactions and outcome among patients with mRCC treated with sunitinib. METHODS: A single-centre, retrospective analysis was performed for patients with mRCC treated with sunitinib. The drug interaction databases 'Clinical Pharmacology' and 'Lexicomp' were used to screen for possible interactions. RESULTS AND DISCUSSION: The hospital files of 36 patients with mRCC were evaluated. Twenty-two patients received sunitinib as first-line treatment. Progression-free survival (PFS) in this first-line group was longer for patients that started with full-dose sunitinib (21·1 months; n = 12) than for patients started on reduced dose (3·5 months; n = 10). In the whole group of 36 patients, an average of 6·8 comedications was taken. Possible pharmacodynamic drug-drug interactions were most frequently found (47%) and reported as major interactions (QT prolongation). Risk of pharmacokinetic interactions due to co-administration of CYP inhibitors, CYP inducers, CYP substrates and PgP substrates was reported for 8%, 11%, 53% and 19%, respectively. These interactions were reported as major or moderate. WHAT IS NEW AND CONCLUSION: Patients with mRCC under treatment with sunitinib at a reduced starting dose had a decreased PFS compared with patients started with full-dose sunitinib. Due to adverse drug reactions and comorbidity, patients under sunitinib, a CYP3A4 substrate, took an average of 6·8 comedications provoking an important risk of major-to-moderate drug-drug interactions. With the help of a multidisciplinary team, avoidance of drug-drug interactions could be obtained. Moreover, serial ECG monitoring is recommended for patients at high risk of QT prolongation.

Imaging requirements for personalized medicine: the oncologists point of view.

While conventional chemotherapy regimens aim to be cytotoxic against proliferating cells, molecular targeted therapies are directed at specific cancer-associated pathways. To optimize cancer care, an early evaluation of treatment response is warranted for any tumor type - and for any treatment - by using conventional imaging modalities such as ultrasound, CT and MR, FDG-PET or specific radiotracer. FDG-PET is one of the most extensively and successfully used imaging modalities to achieve an early response evaluation. A high SUV-value is a surrogate for malignancy in terms of cancer care and a decrease in FDG-uptake after therapy is associated with treatment response and a favorable clinical outcome. Anyhow, the potential of PET reaches further. By providing metabolic information PET (with or without CT) can help to select patients for targeted therapy and to adapt treatment protocols. PET with FDG and maybe other, more specific PET tracers, promises to direct in a better way personalized cancer care and thus promote translational research. An interesting aspect of molecular imaging is the ability to achieve knowledge on distribution and expression levels of a given receptor. Hereby, imaging could help in guiding systemic treatment given a broad spectrum of radiotracers, detecting specific mutations at molecular level in vivo. From an oncologists point of view the concept of 'personalized medicine' should evolve to include 'personalized imaging' as well as 'personalized treatment' in order to optimize cancer care, reduce side effects and improve quality of life for cancer patients.

Nephrotoxicity of anticancer drugs--an underestimated problem?

Nephrotoxicity is an inherent adverse effect of certain anticancer drugs and may result in a variety of functional consequences that include any combination of glomerular or tubular dysfunction, hypertension and disturbance of the renal endocrine function. The nephrotoxic potential of most anticancer agents dramatically increases in the presence of borderline or overt pre-existing chronic kidney disease and measurement of renal function is therefore of utmost importance in the cancer patient before any treatment is initiated. This review summarizes some clinical nephrotoxic side effects of a selection of the most frequently used anticancer drugs. The drugs discussed are cisplatin, methotrexate, ifosfamide, citumixab and panitumumab, mitocin C and gemcitabine and antiangiogenesis drugs.

High dose chemotherapy and stem cell rescue for metastatic germ cell tumours: long-term results from a single institution.

PURPOSE: To evaluate the long term results and the characteristics of patients treated with high dose chemotherapy (HDCT) for an advanced germ cell tumour at Ghent University Hospital from 1996 to 2010. MATERIALS AND METHODS: A retrospective analysis of patients treated with HDCT for germ cell tumours was performed. Data about stage at diagnosis, different prognostic scoring systems, timing of HDCT, response to HDCT and relapse-free period were collected. The following endpoints were evaluated: complete or incomplete response to HDCT, relapse free survival and overall survival time. RESULTS: Of the 148 patients treated with chemotherapy for an advanced germ cell tumour from 1996 to 2010, 10 (6.8%) needed salvage treatment by means of HDCT. Six patients achieved a complete response to one cycle of HDCT and 2 additional patients achieved a complete response to a second cycle of HDCT. A retrospective analysis showed 8 long-term survivors with a maximum follow-up time of 152 months. Two patients were recently transplanted and are not evaluable for survival yet. CONCLUSIONS: Our study suggests that long-term survival can be obtained by means of HDCT for metastatic germ cell tumours, even in patients with bad prognostic features at diagnosis. The question of whether to use 1 or 2 cycles of HDCT still remains unanswered.

PARP inhibitors in oncology: a new synthetic lethal approach to cancer therapy.

Damage to DNA has emerged as a major culprit in cancer. Mammalian cells are continuously exposed to DNA damage, caused by exogenous toxins as well as endogenous activities such as DNA replication and cellular free radical generation. It is therefore essential that cells have DNA repair mechanisms in place to preserve its genomic integrity. Interestingly, cancer cells frequently harbour defects in DNA repair pathways, leading to genomic instability. This can foster tumorigenesis, but also provides a weakness in the tumour that can be exploited therapeutically. In this context, it has been shown that homologous recombination (HR)-deficient tumour cells--including those with defects in BRCA1/2--are highly sensitive to blockade of the base excision repair (BER) pathway via inhibition of the poly (ADP-ribose) polymerase (PARP) enzyme. This provides the basis for a novel 'synthetic lethal' approach to cancer therapy. Recent clinical trials have shown an enhancement of the cytotoxic effect of chemotherapy by adding a PARP inhibitor to the standard treatment. Still, clinical outcome may be even further improved if these drugs would be used as first-line therapy. In conclusion, it can be stated that an exciting new class of drugs has entered the arena of cancer therapy. However, additional clinical studies are needed before PARP inhibitors can definitely enter daily clinical practice.

Fate of insulin analogs in intact and nephrectomized rats determined by their receptor binding constants.

After intravenous injection of 125I-labeled human insulin and analogs in normal and nephrectomized rats, we examined their kinetic fate by Q-Sepharose separation into intact ligand, "fragments" (genuine fragments and protein-bound radioactivity), and iodide. Receptor binding association and dissociation constants (kass and kdis, respectively) of the analogs were estimated dynamically in vitro by BIAcore. The very fast disappearance of intact ligand from serum was found to be determined by 1) both kass and kdis of receptor-bearing tissue, thus substantiating our primary hypothesis; 2) elimination by kidneys, and 3) fast extravascularization. The rate of appearance of degradation products from receptor-mediated intracellular processing seems determined by kdis. With the possible exception of a truncated analog, ligand appears protected against degradation while the intracellular receptor-ligand complex remains intact. Non-receptor-mediated processing in kidneys is slow, compared with the receptor-mediated uptake and degradation of ligands with rate constants comparable to those of insulin. We observed binding of insulin and analogs putatively to serum proteins; binding capacity and affinity appeared insignificant for insulin but considerable for some analogs.

[Sclerosing cholangitis and ulcerative colitis. Regional prevalence]. / Skleroserende cholangitis og colitis ulcerosa. Et regionalt materiale.

The aim of the study was to determine the prevalence of primary sclerosing cholangitis (PSC) in a regional population of patients with ulcerative colitis (UC). Three hundred and five patients with UC followed over a 12 year period were examined for elevations of serum alkaline phosphatase (> 280 U/l). Twenty four such patients were found. If no cause of these elevations were found by initial investigations, endoscopic retrograde cholangiography was performed in order to determine whether they had PSC. Eleven patients were found to have PSC (3.6%), of whom five had progressive disease, including two deaths from cholangio-carcinoma, during a six-year observation period. We found no certain relation between the extent, duration or activity of ulcerative colitis and the presence of PSC. Alkaline phosphatases were elevated up to 3.7 times the upper reference level, the aminotransferases were only found to be mildly elevated.

[Hepatocellular adenoma after oral contraception]. / Hepatocellulaert adenom efter peroral kontraception.

Raised serum basic phosphatase was found incidentally in a woman aged 43 years. Investigation with biopsy revealed a hepatocellular adenoma. The tumour regressed after withdrawal of Neogentrol oral contraception which the patient had consumed for 17 years. The patient did not desire invasive treatment. Employment of oral contraceptive steroids for more than two years is associated with increased occurrence of hepatocellular adenomata. The hepatocellular adenoma is a clearly delimited, most frequently solitary, benign tumour with limited malignant potential but with a considerable risk of rupture with haemorrhage even after withdrawal of oral contraception. The hepatocellular adenoma has no malignant tumour vessels (in contrast to hepatocellular carcinoma) and it appears as a cold region on scintigraphy (in contrast to focal nodular hyperplasia), but the diagnosis can only be established with certainty by histological examination. The hepatocellular adenoma consists most frequently of large pale hepatocytes in trabeculae surrounded by a net of reticulin and separated by sinusoids. Biliary passage and portal spaces do not occur. The best treatment consists of excision of the tumour or embolisation. If invasive treatment is postponed, regular scanning should be performed to observe regression or progression of the tumour and oral contraception and pregnancy should be advised against on account of the risk of growth of the tumour.

Primary sclerosing cholangitis in patients with ulcerative colitis.

The prevalence of primary sclerosing cholangitis (PSC) in patients with ulcerative colitis (UC) attending the Depts. of Medical and Surgical Gastroenterology, Aalborg Hospital, during a 12-year period, was determined. All patients with an alkaline phosphatase (ALP) value above the normal range were investigated. Of 305 patients with UC, 24 patients had elevated ALP values, and 11 of these (3.6% of the study population), 4 males and 7 females, were found to have PSC by direct cholangiography. In five patients the disease worsened (two patients died of cholangiocarcinoma), in four it was stationary, and in two patients the disease improved during a mean observation period of 6 years. No differences in location of disease, disease activity, or duration of disease were found between patients with UC and PSC and patients with UC without PSC. The ALP values were raised to a mean of 3.7 times the upper normal limit (observed range, 1.5-5.5 times the upper normal limit). Aspartate aminotransferase was moderately elevated in most patients, but no other abnormal biochemical liver test results were observed at onset. The results of our study indicate that PSC is the major cause of raised ALP values in patients with UC; thus cholangiography should be performed in UC patients with unexplained elevated ALP levels. A prognostic indicator is needed to predict the individual prognosis and to determine the optimal timing of liver transplantation.

Receptor binding and tyrosine kinase activation by insulin analogues with extreme affinities studied in human hepatoma HepG2 cells.

The insulin-receptor affinity of five human insulin analogues with one to four amino acid substitutions was measured with human hepatoma cells (HepG2). The binding affinities ranged from 0.05% for AspB25 insulin, 18% for AspB9, GluB27 insulin, 80% for AspB28 insulin, and 327% for AspB10 insulin to 687% for HisA8, HisB4, GluB10, HisB27 insulin relative to human insulin. Binding constants obtained by competition experiments at steady state with [125I]TyrA14-labeled insulin and unlabeled analogues and by kinetic studies with [125I]TyrA14-labeled analogues and insulin gave essentially the same values. The kinetic studies showed that differences in affinity between analogues were due to differences in both dissociation and association rate constants. The affinity for insulinlike growth factor I receptor was low, ranging from less than 0.005% for AspB25 insulin to 0.6% for HisA8, HisB4, GluB10, HisB27 insulin. The potencies of insulin analogues in activation of the tyrosine kinase of solubilized and partially purified insulin receptors from HepG2 cells, measured with the exogenous substrate poly(Glu80-Tyr20), ranked in the same order as the binding affinities, the actual values being somewhat elevated for the high-affinity analogues, however. We conclude that these human insulin analogues are active in insulin-receptor binding and tyrosine kinase stimulation but show wide variation in affinity.

Scintigraphic studies in rats. Kinetics of insulin analogues covering wide range of receptor affinities.

Whole-body kinetics of 123I-labeled human insulin and five insulin analogues were investigated by scintigraphic studies in rats. The amino acid substitutions and the relative receptor affinities (RAs), determined by binding to HepG2 cells, were: GluB12, des-B30 insulin, RA 0.15%; AspB9, GluB27 insulin, RA 18%; AspB26 insulin, RA 80%; AspB18 insulin, RA 327%; and HisA8, HisB4, GluB10, HisB27 insulin, RA 687%. All analogues were compared with human insulin (RA 100%). The analogue with RA 0.15% showed a significantly slower disappearance in the heart window, no liver uptake, and the greatest kidney radioactivity, the latter probably caused by high plasma concentrations. The low-affinity analogue (RA 18%) reached a surprisingly high hepatic peak value, although significantly lower than insulin. Kidney radioactivity was higher than for insulin. The analogue with RA 80% showed liver and kidney radioactivities that were not significantly different from those of insulin. The two high-affinity analogues (RAs 327 and 687%) showed peak liver radioactivities not significantly different from insulin. However, liver radioactivity after the peaks declined significantly more slowly. Compared with insulin, the kidney radioactivity curves were not significantly different. We conclude that high-affinity insulin analogues will bind to any available receptor that, because of the large number of receptors in the periphery and the distribution of cardiac output, favors extrahepatic elimination. In contrast, low-affinity analogues bind to receptors several times before they are eliminated. This leads to recirculation and, thus, hepatic elimination due to the high receptor density there. It follows that hepatopreferential binding cannot be expected solely by use of an insulin analogue with a particular receptor affinity.

Systematic variation and differences in insulin-autoantibody measurements.

Insulin autoantibodies (IAAs) are currently the subject of intensive investigation as potential markers for autoimmune insulitis. However, the results of different reports vary widely. In an attempt to elucidate the reasons for the discrepant reports and to initiate standardization procedures, the International Diabetes Workshop (IDW) undertook two studies in which 22 centers worldwide measured IAA in coded samples. The variance in binding signal from the 49 sera in study 1 was considerable, even when results were standardized, but was largely systematic and attributable to basic differences in assay type (liquid phase versus solid phase) and to differences in the ligand used (human vs. nonhuman insulin). In study 2, 5 sera were prepared and presented blindly to compare dilution curves, insulin-species specificity, interference from irrelevant serum proteins, precision, and dose-dependent displaceability. Many assays, both liquid and solid phase, were influenced by marked and unpredictable nonspecific binding, revealed by loss of parallelism between dilution curves in pooled normal serum and buffer, by variable binding signals with different normal sera, and by difficulty in distinguishing human insulin-specific from cross-reactive IAA sera. It was concluded from the experience of both studies that variance could probably be reduced by using a standard curve with derived common units, a single species of ligand, and methodology to minimize the effect of nonspecific binding. Variation related to assay type was probably due to liquid- versus solid-phase systems being differentially more sensitive to certain aspects of antigen-antibody binding; this issue will be addressed in future serum exchanges and workshops.

Characterization of monoclonal antibodies against bovine insulin.

Six different monoclonal antibodies (IgG1 and IgG2a) were obtained after fusions of X63-Ag8-6.5.3 myeloma cells with spleen cells from BALB/c mice immunized with bovine insulin. Definition of binding determinants was attempted by competitive binding studies with insulins, proinsulins and modified insulins from various species. The monoclonal antibodies OXI-001 and OXI-004 were inferred to react with a region including residue A10, OXI-002 with an antigenic determinant in the B26-30 region, OXI-005 with a region including B30 and OXI-006 with a tertiary structure near the N-terminus of the B chain, possibly including B3 and A10. The equilibrium binding constants for these antibodies were calculated by three different methods (Scatchard, Langmuir and non-linear regression) and were found to be in the range of 2 X 10(7)-8 X 10(9), with good agreement between the different methods of calculation. As expected for a given monoclonal antibody, the heterogeneity index was close to 1.0, as calculated from Sip's logarithmic transformation of the binding equation. These parameters were compared to those of a mixture of the six different monoclonal antibodies and those of a conventional hyperimmune anti-insulin serum (guinea-pig). The half-dissociation times (t1/2) of complexes of antibody and bovine insulin ranged from 35 min to 38 h.

Effect of insulin antibodies on insulin pharmacokinetics and glucose utilization in insulin-dependent diabetic patients.

To determine the impact of insulin-binding antibodies on total (TIRI) and free insulin (FIRI) as well as on insulin sensitivity, 10 insulin-dependent diabetic patients (IDDM) with poststimulatory C-peptide less than 100 pmol/L and an insulin binding capacity (IBC) between less than 1 and 294 micrograms/L serum were studied during and after a 1-h nonprimed, constant-rate insulin infusion (study 1: 0.057 U/kg body wt, study 2: 0.286 U/kg body wt). Euglycemia was maintained by variable glucose infusion. Control studies were performed in 5 healthy subjects. Basal TIRI (mU/L) was lowest in healthy subjects (16 +/- 1 [SE]) and elevated in diabetic patients (IBC less than 25 micrograms/L: 72 +/- 11, IBC greater than 25 micrograms/L: 1772 +/- 842), whereas serum concentrations of FIRI were considerably smaller but still two- to threefold greater (P less than 0.01) in the patients than in healthy subjects (13 +/- 1). After intravenous (i.v.) insulin administration, almost identical increments in serum TIRI were seen in healthy subjects and in diabetic patients with low IBC (less than 25 micrograms/L), whereas those with high IBC (greater than 25 micrograms/L) had a heterogeneous response.(ABSTRACT TRUNCATED AT 250 WORDS)