Plasma citrulline levels as a biomarker for bowel toxicity in prostate stereotactic radiotherapy with or without pelvic nodal radiation

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Background: Plasma levels of citrulline, an amino acid, are derived mainly from small bowel enterocytes. Decreased levels occur in a range of bowel conditions and citrulline has been proposed as a biomarker of bowel toxicity in pelvic radiotherapy. In a prospective study, we identify no correlation between plasma citrulline and toxicity in men receiving prostate stereotactic radiotherapy randomized to receive either pelvic nodal irradiation or not. Furthermore, citrulline levels were not significantly different between these two groups. Methods: As part of an approved clinical trial, men with intermediate to high risk prostate cancer were randomised 1:1 to prostate only or prostate + pelvic nodal radiotherapy, delivered with a rectal spacer gel in situ. The prostate and proximal seminal vesicles received 40 Gy in 5 fractions. Those randomised to the pelvic nodal arm also received 25 Gy in 5 fractions to pelvic nodes. Citrulline was measured at 10 points during treatment – consent, before fraction 1, 1 and 24 hours following fraction 1, prior to each fraction 2 – 5 and at 6 weeks’ and 3 months’ follow up. Bowel toxicity was measured by EPIC patient reported scores. Results: 16 men with follow up of at least 3 months (median 9, maximum 18 months) were analysed. Reported toxicity was significantly higher in the prostate and pelvis arm: 5 of 9 men showed a decrease in EPIC bowel domain summary score of 10 points or more compared to 0 of 7 in the prostate-only arm (p = 0.0337, two tailed Fisher’s exact test). No significant correlation between toxicity and citrulline levels was seen, nor did citrulline vary significantly between arms or fall as treatment progressed. Data analysis for a further 8 men already recruited to the study is ongoing. Conclusions: Toxicity was more commonly reported by men randomised to receive pelvic radiotherapy, suggesting that the small bowel irradiated in pelvic fields plays a role in bowel toxicity experienced during stereotactic radiotherapy. Citrulline levels showed no significant correlation with toxicity or radiation dose to small bowel. We propose that citrulline is not a useful biomarker of small bowel toxicity in this setting. Clinical trial information: NCT03253978.

Serotonergic regulation of insulin secretion

The exact physiological role for the monoamine serotonin (5-HT) in modulation of insulin secretion is yet to be fully understood. Although the presence of this monoamine in islets of Langerhans is well established, it is only with recent advances that the complex signalling network in islets involving 5-HT is being unravelled. With more than fourteen different 5-HT receptors expressed in human islets and receptor-independent mechanisms in insulin-producing β-cells, our understanding of 5-HT's regulation of insulin secretion is increasing. It is now widely accepted that failure of the pancreatic β-cell to release sufficient amounts of insulin is the main cause of type 2 diabetes (T2D), an ongoing global epidemic. In this context, 5-HT signalling may be of importance. In fact, 5-HT may serve an essential role in regulating the release of insulin and glucagon, the two main hormones that control glucose and lipid homoeostasis. In this review, we will discuss past and current understanding of 5-HT's role in the endocrine pancreas.

I Still Haven't Found What I'm Looking For... Bono, Google and Glaucoma Awareness

The effect of celebrity diagnosis on public awareness of health conditions has already been well documented. In October 2014, Bono, the lead singer with U2, revealed publicly for the first time that he has glaucoma. This study aimed to analyze the impact of Bono's announcement on public awareness of glaucoma using Google Search trends as an indicator of public interest in the disease. Google Trends was used to examine Google Search activity for the term 'Glaucoma' between 2009 and 2015 in both Ireland and the United Kingdom. Trend analyses were performed using Microsoft Excel Version 14.3.5. Increased Google Search activity for 'Glaucoma' in October 2014 was found in both Ireland and the United Kingdom. A five-fold increase from the mean Google Search activity for this term was found in Ireland and a two-fold increase from the mean Google Search activity for this term was found in the United Kingdom. No such increase in Google Search activity occurred during each country's 2014 Glaucoma Awareness week. Google Trends is useful in medical research as a means of assessing public awareness of, and/or interest in, health related topics. Current approaches to glaucoma related health promotion in both Ireland and the United Kingdom have failed to yield an increase in on-line Google Search activity. While there was an increase in interest in glaucoma it is unclear whether this led to an increase in health seeking behaviour.

A metastatic biology gene expression assay to predict the risk of distant metastases in patients with localized prostate cancer treated with primary radical treatment

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Background: Approximately 20% of patients with organ confined prostate cancer (PCa) will develop disease recurrence following radical treatment (surgery or external beam radiotherapy (EBRT)). We hypothesized that a molecular subgroup of early PCa may have metastatic potential at presentation, resulting in disease recurrence. Methods: Using unsupervised hierarchical clustering of gene expression from a PCa dataset we identified a novel molecular subgroup with a transcriptional profile similar to metastatic disease. We developed a 70 gene expression assay to prospectively identify patients within the subgroup from formalin fixed and paraffin embedded tissue (FFPE). Initial assessment found the assay to be prognostic in three independent publicly available prostatectomy datasets. We therefore assessed the prognostic value of the assay in FFPE clinical samples collected from multiple international sites. FFPE tumor resections and tumor biopsy specimens were obtained from 322 surgical patients and 248 patients treated with EBRT. Regions of highest Gleason grade were identified for macrodissection, RNA extraction and gene expression analysis. Samples were dichotomized as metastatic biology assay positive or negative using a pre-specified cut-off. The association of assay results with biochemical failure (BF) and distant metastases (DM) was tested on multivariate (MVA). Results: The assay was significantly associated with BF on MVA (HR 1.67 [1.16-2.38]; p = 0.0059), (HR 2.26 [1.26-4.04]; p = 0.0062) and DM on MVA (HR 3.39 [1.88-6.12]; p = 0.0001), (HR 3.26 [1.27-8.30]; p = 0.0137) for surgery and EBRT cohorts respectively. Importantly, in a combined model, the assay demonstrated additional information to the commonly used CAPRA clinical tool for prediction of DM, HR 2.72 [2.10-3.51]; p < 0.0001, and HR 2.72 [1.42-5.20]; p = 0.0026 (Prostate Metastatic Assay combined with CAPRA-S and CAPRA respectively). Conclusions: The metastatic biology assay predicts BF and DM in PCa patients treated with surgery or EBRT. The assay may help to select patients at risk of metastatic disease for additional treatment aimed at preventing disease recurrence.

Refractory patella tendinopathy with failed conservative treatment-shock wave or arthroscopy?

AIM

To identify whether the location of refractory patella tendinopathy (PT) has an effect on treatment modality (radial extracorporeal shock wave therapy (rESWT) or arthroscopic debridement).

METHODS

Between 2012 and 2014, 40 patients with PT underwent a magnetic resonance imaging (MRI) scan. This confirmed the diagnosis as either involving the tendon itself (group A, 20) or with retropatella fat pad extension (group B, 20). All patients underwent rESWT. If there was no improvement patients proceeded with surgery in the form of arthroscopic debridement (by senior authors CW and AG). Outcomes were assessed before and after treatment using the Victorian Institute of Sports Assessment-Patella (VISA-P) score.

RESULTS

There were 18 males and 2 females in group A and 15 males and 5 females in group B. The mean age was 41.4 years in group A (23-59) and 34.7 in group B (19-52). Seventeen of 20 in group A reported good or excellent outcomes and did not require surgical intervention (remaining three improved after second course of ESWT). All patients in group B failed to improve with rESWT, resulting in arthroscopic debridement and reported good or excellent outcomes. After 6 months, group A mean VISA-P score increased from 50.2 to 65.0 ( p = 0.01) and group B from 39.6 to 78.4 ( p = <0.001).

CONCLUSION

An MRI should be performed to determine the precise location of tendinosis in patients with refractory PT who fail standard conservative management. If the MRI scan shows intratendon changes only, ESWT should be performed and those with extension into the fat pad should proceed to arthroscopic debridement without rESWT.

Does the choice of hormone therapy affect medium-term outcomes following radical external beam radiotherapy for localized prostate cancer?

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Background: Multiple randomized controlled trials (RCTs) have demonstrated the benefit of the addition of androgen deprivation therapy (ADT) to external beam radiotherapy (EBRT) in the treatment of men with localized prostate cancer (PC). Anti-androgens (AA) may have a better toxicity profile than luteinizing hormone-releasing hormone agonists (LHRHa). However, no RCT has directly compared these agents in combination with radical EBRT. We evaluated outcomes for men with localized PC treated with EBRT in conjunction with either LHRHa or AA therapy. Methods: Data from 409 consecutive patients treated in NI with radical EBRT (70-74 Gy/2Gy #) between 2005 and 2009 were reviewed. Baseline and treatment characteristics analysed comprised age at diagnosis, T stage, initial PSA (iPSA), Gleason score, age-adjusted Charlson comorbidity index (aCCI), ADT type and radiation dose. Outcomes included biochemical progression-free survival (bPFS; Phoenix), prostate cancer-specific survival (PCSS) and overall survival (OS). Cox Proportional Hazards model was used for multivariate analysis (MVA). Results: Men receiving LHRHa were significantly more likely to be older and have a higher iPSA. On MVA, factors independently associated with biochemical failure were T stage ≥ 3 and use of AA (p < 0.004 and p < 0.02 respectively). On MVA, the single independent factor for poorer OS was higher aCCI (p < 0.000015). There was a trend towards poorer OS in the LHRHa group (p = 0.087). Conclusions: An aCCI > 4 was the only independent factor for poorer OS. While there was a significantly increased rate of biochemical failure in the AA group, there was a trend towards poorer OS in the LHRHa group. This study suggests that AA may be a reasonable alternative to LHRHa therapy in men with localized PC treated with radical EBRT and ADT. [Table: see text]

Impact of pre-treatment neutrophil-lymphocyte ratio on outcomes in men receiving radical external beam radiotherapy for localised prostate cancer

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Background: There is a shortage of novel biomarkers in clinical use for the diagnosis and management of prostate cancer. The neutrophil-lymphocyte ratio (NLR) is a potentially useful biomarker derived from a standard full blood count from peripheral blood sampling, which is readily available and relatively inexpensive. An elevated NLR has been shown to be a poor prognostic biomarker in many advanced solid cancers, including prostate cancer (PC); however, data on NLR in non-metastatic PC have been inconsistent. The objective of this study was to evaluate baseline NLR as an independent predictor of outcome following radical radiotherapy for non-metastatic PC. Methods: Data from 477 consecutive PC patients treated with radical EBRT between 2005 and 2009 in Northern Ireland were reviewed. Outcomes included biochemical progression-free survival (bPFS; Phoenix definiton), prostate cancer-specific survival (PCSS) and overall survival (OS). A two-tailed Mann-Whitney test (significance level 5%) was used to compare NLR in each group. Results: Complete data for 409 patients were available. At a median follow-up of 75 months (range 12 – 138), 74 men (16%) had biochemical failure (BF), 12 men (3%) had died of PC, and 65 men (14%) had died of all causes. Actuarial 5-year bPFS was 91%, PCSS was 97% and OS was 89%. Median NLR was 2.42 in both the BF and non-BF groups (p = 0.78), 2.21 and 2.42 in men who died from PC and those who did not (p = 0.39) and 2.40 and 2.42 in those men who died from all causes and those men who remained alive (p = 0.83). See Table for additional data. Conclusions: In this cohort with medium- to long-term follow-up, NLR was not predictive for bPFS, PCSS or OS. Multivariate analysis of this cohort is planned. Additional prognostic biomarkers are required in PC. [Table: see text]