Centralization of Pancreaticoduodenectomy: A Systematic Review and Spline Regression Analysis to Recommend Minimum Volume for a Specialist Pancreas Service

OBJECTIVE

Through a systematic review and spline curve analysis, to better define the minimum volume threshold for hospitals to perform (pancreaticoduodenectomy) and the high volume centre (HVC).

SUMMARY BACKGROUND DATA

The pancreaticoduodenectomy (PD) is a resource intensive procedure, with high morbidity and long hospital stays resulting in centralization towards high-volume hospitals; the published definition of high-volume remains variable.

MATERIALS AND METHODS

Following a systematic review of studies comparing PD outcomes across volume groups, semiparametric regression modelling of morbidity (%), mortality (%), length of stay (days), lymph node harvest (number of nodes) and cost ($USD) as continuous variables was performed and fitted as a smoothed function of splines. If this showed a non-linear association, then a "zero-crossing" technique was used which produced "first and second derivatives" to identify volume thresholds.

RESULTS

Our analysis of 33 cohort studies (198,377 patients) showed 55 PDs/year and 43 PDs/year were the threshold value required to achieve lowest morbidity and highest lymph node harvest, with model estimated degrees of freedoms 5.154 (P<0.001) and 8.254 (P<0.001) respectively. The threshold value for mortality was approximately 45 PDs/year (model 9.219 (P <0.001)) with the lowest mortality value (the optimum value) at approximately 70 PDs/year (i.e. a high volume centre). No significant association was observed for cost (e.d.f=2, P=0.989), and length of stay (e.d.f=2.04, P=0.099).

CONCLUSIONS

There is a significant benefit from centralization of PD, with 55 PDs/year and 43 PDs/year the threshold value required to achieve lowest morbidity and highest lymph node harvest respectively. To achieve mortality benefit, the minimum procedure threshold is 45 PDs/year, with the lowest and optimum mortality value (i.e. a high volume center) at approximately 70 PDs/year.

Evaluation of post-operative surveillance strategies and surgeon perceptions and beliefs of surveillance for pancreatic ductal adenocarcinoma in the UK

BACKGROUND

Despite high rates of recurrence after surgery for pancreatic ductal adenocarcinoma (PDAC) there is lack of standardised surveillance practices. We aimed to identify UK surveillance practice and interrogate surgeon beliefs around surveillance.

METHODS

A web-based survey was sent to all UK pancreatic units to assess surveillance practice for resected PDAC, factors influencing surveillance protocols, and perceptions and beliefs surrounding on current postoperative surveillance.

RESULTS

There was wide variation in reported practice between 40 consultant surgeons from 28 pancreatic units (100% unit response rate). 26% had standardised surveillance compared to 18% with no standardised practice. 16% individualised surveillance to the patient, and 40% reported differing practices between surgeons within units despite local surveillance protocols. 66% felt surveillance should be tailored to patient factors, and 58% to patient preference. There was a broad belief regarding a lack of robust evidence supporting surveillance making a trial necessary. Thematic analysis identified surveillance barriers, considerations for trial design, necessity for patient engagement and potential benefits of surveillance.

DISCUSSION

Wide variation in surveillance practice exists within and between units. A surveillance trial was deemed beneficial, however identified barriers potentially preclude a trial. Future work should assess acceptability for patients including impact on anxiety and quality-of-life.

The impact of the COVID-19 pandemic upon pancreatic cancer treatment (CONTACT Study): a UK national observational cohort study

INTRODUCTION

CONTACT is a national multidisciplinary study assessing the impact of the COVID-19 pandemic upon diagnostic and treatment pathways among patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

The treatment of consecutive patients with newly diagnosed PDAC from a pre-COVID-19 pandemic cohort (07/01/2019-03/03/2019) were compared to a cohort diagnosed during the first wave of the UK pandemic ('COVID' cohort, 16/03/2020-10/05/2020), with 12-month follow-up.

RESULTS

Among 984 patients (pre-COVID: n = 483, COVID: n = 501), the COVID cohort was less likely to receive staging investigations other than CT scanning (29.5% vs. 37.2%, p = 0.010). Among patients treated with curative intent, there was a reduction in the proportion of patients recommended surgery (54.5% vs. 76.6%, p = 0.001) and increase in the proportion recommended upfront chemotherapy (45.5% vs. 23.4%, p = 0.002). Among patients on a non-curative pathway, fewer patients were recommended (47.4% vs. 57.3%, p = 0.004) or received palliative anti-cancer therapy (20.5% vs. 26.5%, p = 0.045). Ultimately, fewer patients in the COVID cohort underwent surgical resection (6.4% vs. 9.3%, p = 0.036), whilst more patients received no anti-cancer treatment (69.3% vs. 59.2% p = 0.009). Despite these differences, there was no difference in median overall survival between the COVID and pre-COVID cohorts, (3.5 (IQR 2.8-4.1) vs. 4.4 (IQR 3.6-5.2) months, p = 0.093).

CONCLUSION

Pathways for patients with PDAC were significantly disrupted during the first wave of the COVID-19 pandemic, with fewer patients receiving standard treatments. However, no significant impact on survival was discerned.

Ursodeoxycholic acid in the management of symptomatic gallstone disease: systematic review and clinician survey

BACKGROUND

Symptomatic gallstones are common. Ursodeoxycholic acid (UDCA) is a bile acid that dissolves gallstones. There is increasing interest in UDCA for symptomatic gallstones, particularly in those unfit for surgery.

METHOD

A UK clinician survey of use and opinions about UDCA in symptomatic gallstones was performed, assessing clinicians' beliefs and perceptions of UDCA effectiveness. A systematic review was performed in accordance with the PRISMA guidelines. PubMed, MEDLINE, and Embase databases were searched for studies of UDCA for symptomatic gallstones (key terms included 'ursodeoxycholic acid'; 'UDCA'; 'biliary pain'; and 'biliary colic'). Information was assessed by two authors, including bias assessment, with independent review of conflicts.

RESULTS

Overall, 102 clinicians completed the survey, and 42 per cent had previous experience of using UDCA. Survey responses demonstrated clinical equipoise surrounding the benefit of UDCA for the management of symptomatic gallstones, with no clear consensus for benefit or non-benefit; however, 95 per cent would start using UDCA if there was a randomized clinical trial (RCT) demonstrating a benefit. Eight studies were included in the review: four RCTs, three prospective studies, and one retrospective study. Seven of eight studies were favourable of UDCA for biliary pain. Outcomes and follow-up times were heterogenous, as well as comparator type, with only four of eight studies comparing with placebo.

CONCLUSION

Evidence for UDCA in symptomatic gallstones is scarce and heterogenous. Clinicians currently managing symptomatic gallstone disease are largely unaware of the benefit of UDCA, and there is clinical equipoise surrounding the benefit of UDCA. Level 1 evidence is required by clinicians to support UDCA use in the future.

Outcomes of patients undergoing elective liver and pancreas cancer surgery during the SARS-CoV-2 pandemic: an international, multicentre, prospective cohort study

BACKGROUND

The effect of SARS-CoV-2 infection upon HPB cancer surgery perioperative outcomes is unclear. Establishing risk is key to individualising treatment pathways. We aimed to identify the mortality rate and complications risk for HPB cancer elective surgery during the pandemic.

METHODS

International, prospective, multicentre study of consecutive adult patients undergoing elective HPB cancer operations during the initial SARS-CoV-2 pandemic. Primary outcome was 30-day perioperative mortality. Secondary outcomes included major and surgery-specific 30-day complications. Multilevel cox proportional hazards and logistic regression models estimated association of SARS-CoV-2 and postoperative outcomes.

RESULTS

Among 2038 patients (259 hospitals, 49 countries; liver n = 1080; pancreas n = 958) some 6.2%, n = 127, contracted perioperative SARS-CoV-2. Perioperative mortality (9.4%, 12/127 vs 2.6%, 49/1911) and major complications (29.1%, 37/127 vs 13.2%, 253/1911) were higher with SARS-CoV-2 infection, persisting when age, sex and comorbidity were accounted for (HR survival 4.15, 95% CI 1.64 to 10.49; OR major complications 3.41, 95% CI 1.72 to 6.75). SARS-CoV-2 was associated with late postoperative bleeding (11.0% vs 4.2%) and grade B/C postoperative pancreatic fistula (17.9% vs 8.6%).

CONCLUSION

SARS-CoV-2 infection was associated with significantly higher perioperative morbidity and mortality. Patients without SARS-CoV-2 had acceptable morbidity and mortality rates, highlighting the need to protect patients to enable safe ongoing surgery.

P-P53 Textbook outcomes in pancreatoduodenectomy are improved in high volume specialist pancreas-only centres

Background

Traditional single surgical quality indicators are commonly used however they are poor for assessing global outcomes for patients. Composite outcomes such as the ‘Textbook Outcome’ (TO) is a composite outcome to determine the success of the quality of the surgical process, and compare outcomes between institutions and patient groups, described by the Dutch Pancreatic Cancer Audit Group for Pancreatoduodenectomy (PD).  They reported national TOs for PD of 58.3%, we compared this to TOs in a UK high volume specialist pancreas-only centre, Royal Stoke. 

Methods

Patients who underwent PD from January 2017 to December 2020 were identified from our database. TO was defined as absence the following: post-operative pancreatic fistula (POPF) (grade B/C), post-pancreatectomy haemorrhage (PPH), bile leak, severe complications (Clavien Dindo grade III or more), 30-day readmission and 30-day mortality. 

Results

153 patients underwent PD during the 4-year study period. The median age was 71years (range 37-85 years), and there was a slight male preponderance (54.9%, 84/153).  47% had pancreatic ductal adenocarcinoma (72/153), 17% ampullary carcinoma (26/153), 9% cholangiocarcinoma (14/153), 9% duodenal carcinoma (14/153), and benign pathology included cases with IPMN and duodenal polyps with high grade dysplasia. There was a statistically significant difference in textbook outcome in our cohort compared to the Dutch Study (70.3%, 108/153 vs 58.3%, 895/1536; p=0.003086), with components of TO shown in Figure 1.

Conclusions

TO represent composite outcome for identifying good practice, areas for shared learning and areas for improvement. PD performed in high-volume pancreas-only specialist centers appear to have better outcomes following PD than lower-volume centres.  Further investigation is required to assess why outcomes are different between centres, and identify how best practice can be shared. 

P-O17 The Royal Stoke Green Pathway: a method to undertake safe UGI surgery during the COVID pandemic

Background

During the first wave of the COVID pandemic surgical services we paralysed globally, with cancellation of an estimated 28-million operations during the first 12 weeks.  Worryingly, surgical patient with COVID were reported to have unacceptably high peri-operative mortality, approaching 25%.  However, there was an urgent clinical need to progress with category 1 and 2 operations, to prevent disease progression and avoidable morbidity and mortality from non-COVID pathologies.  During the second and subsequent waves of the pandemic it was vital to protect patients from peri-operative COVID whilst undertaking urgent surgery safely.

Methods

Our centre developed a ring-fenced 'Green Pathway' for category 1 and 2 patients requiring surgery.  Patients were treated in physically separate area of the hospital, with no interaction between COVID and non-COVID patients, healthcare staff or facilities.  Patients self-isolated for 14-days prior to admission, and had pre- and peri-operative COVID RT-PCR tests.  We assessed outcomes for patients immediately prior to the introduction of the Green Pathway (1/10/2020) and following implementation (31/12/2020) to assess safety. Textbook outcomes for pancreatoduodenectomy were compared to assess safety and quality.  Other data suggests that UGI surgery couldn't continue in other hospitals from December 2020.

Results

There were 47 admissions to surgical HDU following category 1 and 2 upper GI operations during the study; 31 pre-pathway (PP) implementation, and 16 green pathway (GP) patients.

Median age 66-years (43-78 range) PP vs 65-years (range 42-74) GP, median ASA 3 vs 2. Median HDU length of stay (LOS) 5-days vs 7-days, and median hospital LOS 11.5-days vs 9-days for PP vs GP respectively. There were 6 cases of peri-operative COVID in PP cohort, and 1 in GP (contract following discharge). There was no mortality within either cohort. For the subgroup of patients undergoing PD: 10 patients PP, 6 patients GP, textbook outcomes were achieved in 90% vs 67% PP vs GP.

Conclusions

The implementation of the Green Pathway at our institution enabled continuation of surgery for patients with category 1 and 2 operations during the COVID pandemic with a significant reduction in peri-operative COVID infection, no mortality and no increase in length of stay. The TO rate was lower with the GP (not statistically significant), but our 4-year institution TO rate is 70.3%, comparing favourably to other studies.  This pathway has enabled safe continuation of urgent surgery during the pandemic and could be a model for adoption in other centres especially if there is resurgence of COVID cases during the coming winter.

P-P55 CT-PET use in potentially resectable pancreatic cancer

Background

CT-PET has become increasingly used in the diagnostic pathway for pancreatic cancer (PC)and was introduced into National Guidelines (NICE) in 2018 in the United Kingdom. It can improve the diagnosis of metastatic disease, though some believe it is not significantly better than a staging CT and MRI, and there are concerns that it can significantly delay the treatment pathway for patients, without adding benefit.

Methods

A retrospective national study undertaken by 26/27 specialist pancreatic resectional centres in the United Kingdom. All adult patients listed for pancreatoduodenectomy for suspected PC were included. Baseline demographics, length of pathway (days from MDT to surgery), number and type of investigations, interventions (ERCP or PTC) and associated complications were recorded, in addition to the operation performed and 12-month survival. Patients undergoing neoadjuvant chemotherapy were excluded.

Results

1709 cases were entered from 2017-2020. 155 patients were excluded due to neoadjuvant chemotherapy, with 8 further patients excluded due to incomplete data entry. The median age was comparable for patients undergoing CT-PET (68 years IQR 60.0-73.0) and those who did not undergo CT PET (68 years IQR 60.0-74.0). 363/1546 patients (23.5%) underwent a pre-operative CT-PET. There was a significantly longer pathway with CT-PET (56 vs 42 days, p &lt; 0.001) and a non-significant tendency towards an increased bypass rate with CT-PET (9.9% vs. 7.8%, p = 0.065), and no improvement in survival (1-year survival 76.9% vs 75.7%, p = 0.712).

Conclusions

There is a statistically significant increase in the length of pathway with CT-PET, without any improvement in bypass rate or one year survival compared the no-CT-PET group.  CT-PET undoubtedly has benefits but should be used selectively rather as standard investigation for all patients as failed to demonstrate survival improvement.

O-P08 Optimising design of national collaborative studies in surgery: national availability of electronic data in the NHS

Background

Clinical trials are constrained in part by cost and limited funding opportunities. Trainee-led collaborative, multi-centre research models have become increasingly popular, enabling clinicians to undertake impactful national and international practice-changing studies with limited funding. However, ensuring equitable and efficient data collection from participating centres requires understanding data accessibility. Here, we reflect upon our strategies in designing and delivering collaborative research (The RICOCHET Study). Specifically, we consider the availability of data sources for UK hospitals, to enable effective design of study case report forms to ensure study success.

Methods

RICOCHET was a National trainee-led audit of UK hospitals treating patients with pancreatic cancer. All registered hospitals were asked to complete a site-survey at point of registration. The site survey was completed by the lead consultant (surgeon or gastroenterologist) or the lead trainee at each site. The site-survey detailed hospital demographics, including size, availability of services and availability of patient data electronically. The survey was completed online via REDCap. Sites lacking full reporting were excluded from the analyses.

Results

98 UK sites registered for RICOCHET, and 94 completed the site-survey (26 specialist pancreatic sites; 68 non-specialist sites). 100% sites had electronic radiology reports. However, electronic ward-round notes were available at only 19% (5/26, 19.2% specialist vs. 13/68, 19.1% non-specialist; p = 0.99). Furthermore, sources such as external letters were low (29%; 11/26 42.3% specialist vs. 16/68, 23.5% non-specialist; p = 0.072). Although electronic interventional radiology reports were broadly available at 79% sites, this was significantly lower at non-specialist sites (49/68 72.1% vs. 25/26 96.2%; p = 0.011).

Conclusions

Availability of electronic data is not consistent across sites managing pancreatic cancer patients. Significant disparity exists between specialist and non-specialist centres, highlighted by lack of availability of interventional radiology reports. To ensure success in trainee-led cohort studies we recommend designing concise case report forms that can be easily completed from electronic data sources. Until this report, there was no data available for the availability of electronic data across the NHS. This represents the most comprehensive report of such data sources, and will guide future study design of national studies at both specialist and non-specialist pancreatic centres in the UK.

Impact of SARS-CoV-2 pandemic on pancreatic cancer services and treatment pathways: United Kingdom experience

INTRODUCTION

The SARS-CoV-2 pandemic presented healthcare providers with an extreme challenge to provide cancer services. The impact upon the diagnostic and treatment capacity to treat pancreatic cancer is unclear. This study aimed to identify national variation in treatment pathways during the pandemic.

METHODS

A survey was distributed to all United Kingdom pancreatic specialist centres, to assess diagnostic, therapeutic and interventional services availability, and alterations in treatment pathways. A repeating methodology enabled assessment over time as the pandemic evolved.

RESULTS

Responses were received from all 29 centres. Over the first six weeks of the pandemic, less than a quarter of centres had normal availability of diagnostic pathways and a fifth of centres had no capacity whatsoever to undertake surgery. As the pandemic progressed services have gradually improved though most centres remain constrained to some degree. One third of centres changed their standard resectable pathway from surgery-first to neoadjuvant chemotherapy. Elderly patients, and those with COPD were less likely to be offered treatment during the pandemic.

CONCLUSION

The COVID-19 pandemic has affected the capacity of the NHS to provide diagnostic and staging investigations for pancreatic cancer. The impact of revised treatment pathways has yet to be realised.

Health-related quality of life, uncertainty and coping strategies in solid organ transplant recipients during shielding for the COVID-19 pandemic

Strict isolation of vulnerable individuals has been a strategy implemented by authorities to protect people from COVID‐19. Our objective was to investigate health‐related quality of life (HRQoL), uncertainty and coping behaviours in solid organ transplant (SOT) recipients during the COVID‐19 pandemic. A cross‐sectional survey of adult SOT recipients undergoing follow‐up at our institution was performed. Perceived health status, uncertainty and coping strategies were assessed using the EQ‐5D‐5L, Short‐form Mishel Uncertainty in Illness Scale (SF‐MUIS) and Brief Cope, respectively. Interactions with COVID‐19 risk perception, access to health care, demographic and clinical variables were assessed. The survey was completed by 826 of 3839 (21.5%) invited participants. Overall, low levels of uncertainty in illness were reported, and acceptance was the major coping strategy (92%). Coping by acceptance, feeling protected, self‐perceived susceptibility to COVID‐19 were associated with lower levels of uncertainty. Health status index scores were significantly lower for those with mental health illness, compromised access to health care, a perceived high risk of severe COVID‐19 infection and higher levels of uncertainty. A history of mental health illness, risk perceptions, restricted healthcare access, uncertainty and coping strategies was associated with poorer HRQoL in SOT recipients during strict isolation. These findings may allow identification of strategies to improve HRQoL in SOT recipients during the pandemic.

Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study

PURPOSE

As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway.

PATIENTS AND METHODS

This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation).

RESULTS

Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76).

CONCLUSION

Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks.

Prospective cohort study of surgical trainee experience of access to gastrointestinal endoscopy training in the UK and Ireland

INTRODUCTION

Surgical trainees are reporting barriers to training in gastrointestinal (GI) endoscopy. This snapshot survey aimed to gather data on variation in access to quality GI endoscopy training for Colorectal and Upper Gastrointestinal (GI) surgical trainees across the UK and Ireland.

MATERIALS AND METHODS

An online 20-point survey was designed and distributed nationally to surgical trainee members of the Association of Surgeons in Training (ASiT), Dukes and The Roux Group (formerly Association of Upper Gastrointestinal Surgeons of Great Britain and Ireland Trainees). The survey was designed in collaboration with The Roux Group for Upper GI trainees and the Dukes' Club for Colorectal trainees.

RESULTS

218 responses were received, most with a Colorectal or Upper GI sub-specialty interest (colorectal 56.0%; upper GI surgery 25.7%). Only 28.6% of trainees attended a dedicated training endoscopy list at least once a week with 28.1% not attending any at all. Less than half of trainees reported having endoscopy formally timetabled on rotas (36.9%). Most trainees (88.0%) encountered difficulties in gaining endoscopy training including lack of available lists (77.2%), conflicting operative commitments (59.4%), preferential allocation of lists to gastroenterology trainees (57.9%) and resistance from endoscopy departmental leads (38.6%). Regarding JAG accreditation, 77.1% respondents felt it should be mandatory prior to CCT with 80.3% believing this would lead to better access to dedicated endoscopy training equivalent to gastroenterology trainees. 93.1% trainees felt that attaining JAG accreditation by surgical trainees was important to patient care.

DISCUSSION

This study demonstrates significant barriers in accessing GI endoscopy training for general surgical trainees which urgently needs to be improved. In order to meet JAG training requirements for surgical trainees, a multifaceted collaborative approach from surgical and gastroenterology training bodies, local JAG trainers and the General Surgery SAC and JCST is required. This is to ensure that endoscopy is promoted and a robust model of training is successfully designed and delivered to general surgery trainees.

Polymorphisms in Natural Killer Cell Receptor Protein 2D (NKG2D) as a Risk Factor for Cholangiocarcinoma

BACKGROUND AND AIMS

Understanding of the significant genetic risk factors for Cholangiocarcinoma (CC) remains limited. Polymorphisms in the natural killer cell receptor G2D (NKG2D) gene have been shown to increase risk of CC transformation in patients with Primary Sclerosing Cholangitis (PSC). We present a validation study of NKG2D polymorphisms in CC patients without PSC.

METHODS

Seven common Single Nucleotide Polymorphisms (SNPs) of the NKG2D gene were genotyped in 164 non-PSC related CC subjects and 257 controls with HaploView. The two SNPs that were positively identified in the previous Scandinavian study, rs11053781 and rs2617167, were included.

RESULTS

The seven genotyped SNPs were not associated with risk of CC. Furthermore, haplotype analysis revealed that there was no evidence to suggest that any haplotype differs in frequency between cases and controls (P > 0.1).

CONCLUSION

The common genetic variation in NKG2D does not correlate significantly with sporadic CC risk. This is in contrast to the previous positive findings in the Scandinavian study with PSC-patients. The failure to reproduce the association may reflect an important difference between the pathogenesis of sporadic CC and that of PSC-related CC. Given that genetic susceptibility is likely to be multifaceted and complex, further validation studies that include both sporadic and PSC-related CC are required.

RNA and microRNA Stability in PAXgene-Fixed Paraffin-Embedded Tissue Blocks After Seven Years' Storage

OBJECTIVES

To evaluate the stability of RNA and microRNA (miRNA) in PAXgene-fixed paraffin-embedded tissue blocks after 7 years' storage.

METHODS

RNA and miRNA were extracted from PAXgene-fixed paraffin-embedded (PFPE) blocks in 2009 then stored at -80°C. Seven years later, RNA and miRNA were again extracted from the same blocks. RNA and miRNA integrity in the 2009 and 2016 extractions were compared using RNA integrity number (RIN), paraffin-embedded RNA metric (PERM), reverse transcription polymerase chain reaction (RT-PCR) for different amplicon lengths, and quantitative RT-PCR (qRT-PCR) for three mRNA and three miRNA targets.

RESULTS

In PFPE blocks, mRNA was poorer in 2016 extractions compared to the 2009 extractions in all blocks and all assays applied, with transcripts degrading at different rates in the same blocks. For miRNA, qRT-PCR showed no statistically significant differences between 2009 and 2016 extractions.

CONCLUSIONS

mRNA in PFPE tissue blocks degrades at room temperature storage over 7 years.

A Critical Evaluation of the PAXgene Tissue Fixation System: Morphology, Immunohistochemistry, Molecular Biology, and Proteomics

OBJECTIVES

To evaluate the PAXgene tissue fixation system.

METHODS

Clinical biospecimens (n = 46) were divided into PAXgene-fixed paraffin-embedded (PFPE), formalin-fixed paraffin-embedded (FFPE), and fresh-frozen (FF) blocks. PFPE and FFPE sections were compared for histology (H&E staining) and immunohistochemistry (14 antibodies) using tissue microarrays. PFPE, FFPE, and FF samples were compared in terms of RNA quality (RNA integrity number, polymerase chain reaction [PCR] amplicon length, and quantitative reverse transcription PCR), DNA quality (gel electrophoresis and methylation profiling) and protein quality (liquid chromatography-mass spectrometry [LC-MS/MS]).

RESULTS

PFPE protocol optimization was required in most cases and is described. RNA extracted from PFPE sections was considerably less degraded than that from FFPE sections but more degraded than that from FF blocks. Genomic-length DNA was extracted from PFPE and FF biospecimens, and methylation profiling showed PFPE and FF biospecimens to be almost indistinguishable. Only degraded DNA was extracted from FFPE biospecimens. PFPE sections yielded peptides that were slightly less amenable to LC-MS/MS analysis than FFPE sections, but FF gave slightly better results.

CONCLUSIONS

While it cannot be envisaged that PAXgene will replace formalin in a routine clinical setting, for specific projects or immunodiagnostics involving biospecimens destined for immunohistochemical or histologic staining and DNA or RNA analyses, PAXgene is a viable option.

Genetic factors in the pathogenesis of cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma (CC) is increasing in incidence, but its pathogenesis remains poorly understood. Chronic inflammation of the bile duct and cholestasis are major risk factors, but most cases in the West are sporadic. Genetic polymorphisms in biliary transporter proteins have been implicated in benign biliary disease and, in the case of progressive familial cholestasis, have been associated with childhood onset of CC. In the current study, five biologically plausible candidate genes were investigated: ABCB11 (BSEP), ABCB4 (MDR3), ABCC2 (MRP2), ATP8B1 (FIC1) and NR1H4 (FXR).

METHODS

DNA was collected from 172 Caucasian individuals with confirmed CC. A control cohort of healthy Caucasians was formed. Seventy-three SNPs were selected using the HapMap database to capture genetic variation around the five candidate loci. Genotyping was undertaken with a competitive PCR-based system. Confirmation of Hardy-Weinberg equilibrium and Cochran-Armitage trend testing were performed using PLINK. Haplotype frequencies were compared using haplo.stats.

RESULTS

All 73 SNPs were in Hardy-Weinberg equilibrium. Four SNPs in ABCB11 were associated with altered susceptibility to CC, including the V444A polymorphism, but these associations did not retain statistical significance after Bonferroni correction for multiple testing. Haplotype analysis of the genotyped SNPs in ATP8B1 identified significant differences in frequencies between cases and controls (global p value of 0.005).

CONCLUSION

Haplotypes in ATP8B1 demonstrated a significant difference between CC and control groups. There was a trend towards significant association of V444A with CC. Given the biological plausibility of polymorphisms in ABCB11 and ATP8B1 as risk modifiers for CC, further study in a validation cohort is required.

Array comparative genomic hybridization identifies novel potential therapeutic targets in cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma (CC) is a rare tumour with a dismal prognosis. As conventional medical management offers minimal survival benefit, surgery currently represents the only chance of cure. We evaluated DNA copy number (CN) alterations in CC to identify novel therapeutic targets.

METHODS

DNA was extracted from 32 CC samples. Bacterial artificial chromosome (BAC) array comparative genomic hybridization was performed using microarray slides containing 3400 BAC clones covering the whole human genome at distances of 1 Mb. Data were analysed within the R statistical environment.

RESULTS

DNA CN gains (89 regions) occurred more frequently than DNA CN losses (55 regions). Six regions of gain were identified in all cases on chromosomes 16, 17, 19 and 22. Twenty regions were frequently gained on chromosomes 1, 5, 7, 9, 11, 12, 16, 17, 19, 20 and 21. The BAC clones covering ERBB2, MEK2 and PDGFB genes were gained in all cases. Regions covering MTOR, VEGFR 3, PDGFA, RAF1, VEGFA and EGFR genes were frequently gained.

CONCLUSIONS

We identified CN gains in the region of 11 useful molecular targets. Findings of variable gains in some regions in this and other studies support the argument for molecular stratification before treatment for CC so that treatment can be tailored to the individual patient.