The diagnostic accuracy of Neuropad for assessing large and small fibre diabetic neuropathy

AIMS

Neuropad is a simple visual indicator test, with moderate diagnostic performance for diabetic peripheral neuropathy. As it assesses sweating, which is a measure of cholinergic small nerve fibre function, we compared its diagnostic performance against established measures of both large and, more specifically, small fibre damage in patients with diabetes.

METHODS

One hundred and twenty-seven participants (89 without diabetic peripheral neuropathy and 38 with) aged 57 ± 9.7 years underwent assessment with Neuropad, large nerve fibre assessments: Neuropathy Disability Score, vibration perception threshold, peroneal motor nerve conduction velocity; small nerve fibre assessments: neuropathy symptoms (Diabetic Neuropathy Symptoms score) corneal nerve fibre length and warm perception threshold.

RESULTS

Neuropad has a high sensitivity but moderate specificity against large fibre neuropathy assessments: Neuropathy Disability Score (> 2) 70% and 50%, vibration perception threshold (> 14 V) 83% and 53%, and peroneal motor nerve conduction velocity (< 42 m/s) 81% and 54%, respectively. However, the diagnostic accuracy of Neuropad was significantly improved against corneal nerve fibre length (< 14 mm/mm2) with a sensitivity and specificity of 83% and 80%, respectively. Furthermore, the area under the curve for corneal nerve fibre length (85%) was significantly greater than with the Neuropathy Disability Score (66%, P = 0.01) and peroneal motor nerve conduction velocity (70%, P = 0.03). For neuropathic symptoms, sensitivity was 78% and specificity was 60%.

CONCLUSIONS

The data show the improved diagnostic performance of Neuropad against corneal nerve fibre length. This study underlines the importance of Neuropad as a practical diagnostic test for small fibre neuropathy in patients with diabetes.

Radiotracers for molecular imaging of cyclooxygenase-2 (COX-2) enzyme

Cyclooxygenase (COX) enzyme is responsible for the formation of important biological mediators including prostaglandins, prostacyclin and thromboxane to trigger many physiological and patho-physiological responses. COXs exist in two distinct isoforms, a constitutively expressed form (COX-1) and an inducible form (COX-2). COX-2 is involved in the body's response to inflammation and pain. Moreover, it has also been shown that COX-2 is overexpressed in many human cancers, and that COX-2 is involved in various neurodegenerative diseases such as Parkinson's and Alzheimer's disease. COX-2 inhibitors are among the most widely used therapeutics for the treatment of chronic and acute pain and inflammation. Non-invasive monitoring of COX-2 functional expression by means of nuclear molecular imaging techniques like positron emission tomography (PET) and single photon emission computed tomography (SPECT) might provide unique opportunities to obtain data on COX-2 expression levels during disease manifestation and progression to study potential roles of COX-2 under various pathological conditions. The present review summarizes recent research efforts directed to the design and synthesis of radiotracers as molecular probes with special emphasis on COX-2 imaging.

Adaptive designs for clinical trials assessing biomarker-guided treatment strategies

BACKGROUND

The Biomarker Strategy Design has been proposed for trials assessing the value of a biomarker in guiding treatment in oncology. In such trials, patients are randomised to either receive the standard chemotherapy treatment or a biomarker-directed treatment arm, in which biomarker status is used to guide treatment.

METHODS

Motivated by a current trial, we consider an adaptive design in which two biomarkers are assessed. The trial is conducted in two stages. In the first stage, patients in the biomarker-guided arm are assessed using a standard and an alternative cheaper biomarker, with the standard biomarker guiding treatment. An analysis comparing biomarker results is then used to choose the biomarker to use for the remainder of the trial. The new biomarker is used if the results for the two biomarkers are sufficiently similar.

RESULTS

We show that in practical situations the first-stage results can be used to adapt the trial without type I error rate inflation. We also show that there can be considerable cost gains with only a small loss in power in the case where the alternative biomarker is highly concordant with the standard one.

CONCLUSIONS

Adaptive designs have an important role in reducing the cost and increasing the clinical utility of trials evaluating biomarker-guided treatment strategies.

High-peak-power, high-energy, high-average-power pulsed fiber laser system with versatile pulse duration and shape

We present a pulsed fiber laser system with average power up to 265 W, pulse energy up to 10.6 mJ, pulse duration adjustable in the range 500 ps-500 ns, repetition rate fully controllable from single-shot operation up to 1 MHz, and the ability to control peak power independently of pulse energy. The system has a compact, all-spliced construction. Such a versatile laser will have wide applications in materials processing.

Eutectic mixture of local anaesthetics (EMLA) 5% cream as a primary dressing on a painful lower leg ulcer

Patients living with chronic leg ulceration may frequently experience moderate to severe wound-related pain, which may not be alleviated by oral analgesics alone. Poorly controlled leg ulcer pain can prevent timely and effective wound management strategies being implemented, and increase wound healing times. Furthermore, patients with poorly controlled leg ulcer pain can experience continuous pain, which significantly affects quality of life. This case report introduces an innovative way of using the eutectic mixture of local anaesthetics (EMLA) 5% cream to reduce wound-related pain, reduce oral analgesic intake, and improve health-related quality of life for a patient with a painful, chronic lower leg ulcer.

Evaluation of glomerular filtration rate estimation by Cockcroft-Gault, Jelliffe, Wright and Modification of Diet in Renal Disease (MDRD) formulae in oncology patients

BACKGROUND

The aim was to evaluate the accuracy of Cockcroft-Gault, Jelliffe, Wright and Modification of Diet in Renal Disease (MDRD) formulae as a substitute for the gold standard measure of glomerular filtration rate (GFR) using chromium 51 EDTA.

PATIENTS AND METHODS

Retrospective analysis of GFR measurements in oncology patients from a University Teaching Hospital over 3 years was carried out. Bias and precision of estimates of GFR were compared with measured GFR.

RESULTS

Six hundred and sixty patients with measured GFR (median 90 ml/min, range 23-179 ml/min) were identified. Cockcroft-Gault produced the smallest bias (median percentage error -1.4%) and highest precision (median absolute percentage error 14.0%) and was the most accurate for carboplatin dosing. For patients>30% over their ideal body weight (IBW), using IBW+30% in the Cockcroft-Gault formula was more precise than using actual body weight or IBW. The Wright formula was most accurate for patients aged 70+years and patients with a body mass index (BMI)≥30 but overestimated GFR when GFR<50 ml/min.

CONCLUSIONS

When measured GFR is unavailable, we advise estimating GFR using the Cockcroft-Gault formula and using IBW+30% for patients weighing>30% over their IBW. If the GFR is ≥50 ml/min and the patient is >70 years and/or BMI≥30, the Wright formula gives the best estimate of GFR.

Molecular and functional characteristics of ovarian surface epithelial cells transformed by KrasG12D and loss of Pten in a mouse model in vivo

Ovarian cancer is a complex and deadly disease that remains difficult to detect at an early curable stage. Furthermore, although some oncogenic (Kras, Pten/PI3K and Trp53) pathways that are frequently mutated, deleted or amplified in ovarian cancer are known, how these pathways initiate and drive specific morphological phenotypes and tumor outcomes remain unclear. We recently generated Pten(fl/fl); Kras(G12D); Amhr2-Cre mice to disrupt the Pten gene and express a stable mutant form of Kras(G12D) in ovarian surface epithelial (OSE) cells. On the basis of histopathologic criteria, the mutant mice developed low-grade ovarian serous papillary adenocarcinomas at an early age and with 100% penetrance. This highly reproducible phenotype provides the first mouse model in which to study this ovarian cancer subtype. OSE cells isolated from ovaries of mutant mice at 5 and 10 weeks of age exhibit temporal changes in the expression of specific Mullerian epithelial marker genes, grow in soft agar and develop ectopic invasive tumors in recipient mice, indicating that the cells are transformed. Gene profiling identified specific mRNAs and microRNAs differentially expressed in purified OSE cells derived from tumors of the mutant mice compared with wild-type OSE cells. Mapping of transcripts or genes between the mouse OSE mutant data sets, the Kras signature from human cancer cell lines and the human ovarian tumor array data sets, documented significant overlap, indicating that KRAS is a key driver of OSE transformation in this context. Two key hallmarks of the mutant OSE cells in these mice are the elevated expression of the tumor-suppressor Trp53 (p53) and its microRNA target, miR-34a-c. We propose that elevated TRP53 and miR-34a-c may exert negatively regulatory effects that reduce the proliferative potential of OSE cells leading to the low-grade serous adenocarcinoma phenotype.

Abstract S4-4: SECRAB: The Optimal SEquencing of Adjuvant Chemotherapy (CT) and RAdiotherapy (RT) in Early Breast Cancer (EBC), Results of a UK Multicentre Prospective Randomised Trial

Background: The optimal sequence of CT and RT for women with EBC has yet to be defined. SECRAB aimed to determine i) if synchronous (Syn) CT-RT improves loco-regional relapse rates (LRR) and ii) whether the treatments could be given together without increased toxicity or compromising the dose intensity of either CT or RT. The first endpoint of this study is presented in this abstract. Methods: SECRAB was a prospective, randomised trial comparing sequential (Seq) to Syn CT-RT. Permitted RT schedules included 40Gy/15F over 3 weeks, 45Gy/20F over 4 weeks and 50Gy/25F over 5 weeks. Syn RT was administered between cycles 2 and 3 for CMF or 5 and 6 for anthracycline-CMF. Syn patients treated using 15F were treated predominantly using a sandwich schedule while those receiving &gt;15F were treated concurrently with CT. Seq RT was delivered on CT completion. Key eligibility criteria were completely excised EBC, fit for and requiring adjuvant CT and RT. The trial was powered to produce a definitive event driven analysis: 150 loco-regional relapses having 85% power to detect 4% 2-sided differences in the primary endpoint of overall LRR. Results: Between Jul 98 and Mar 04, 2296 women were randomised. Baseline characteristics were well balanced. 63% of patients were node positive indicating a high risk population. 2 patients did not receive CT and 23 did not receive RT. 5 patients in the latter group had a loco-regional relapse prior to planned RT (Seq n=3). With a median follow-up of 8.8 years there were 93 and 76 loco-regional relapses in the Seq and Syn arms and 5-year LRR were 7.4% (95% CI 5.9-9.1) and 5.4% (95% CI 4.2-7.0) respectively. There was no significant difference in overall LRR (HRSyn 0.82; 95% CI 0.6-1.1; p=0.19). There was a trend for benefit for Syn treatment which was consistent across different subgroups (grade, lymph node status, tumour size, vascular invasion and excision margin). In an unplanned subgroup analysis, a trend for benefit for Syn treatment was seen predominantly in patients with the presence of lymphovascular invasion (LRR 11.9% Seq vs 8.2% Syn) and also in patients with 0 and 1-3 positive nodes (LRR 7.8% Seq vs 5.2% Syn) but not in those with 4 or more positive nodes. Similar rates were observed for distant recurrences (22.2% vs 22.2%), contralateral recurrences (2.9% vs 2.7%), and new primary cancers (2.9% vs 2.6%) in the Seq and Syn arms respectively. There was also no significant difference in overall survival which was 83% and 82% in the Syn and Seq arms respectively at 5-years (HRSyn 0.99; 95% CI 0.8-1.2; p=0.87). Modest differences in acute skin toxicity and telangiectasia were observed between the two study arms. There was no difference in other late toxicities. The second primary endpoint of safety, toxicity and dose intensity is described in detail elsewhere (abstract no 850168). Conclusions: SECRAB is the largest sequencing trial in EBC to date. Delivering Syn CT-RT using CMF or anthracycline-CMF and a 3 weekly RT fractionation shortens the overall treatment time. Although not statistically significant there was a trend to improved locoregional control with Syn treatment.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr S4-4.