DNAJB12 and Hsp70 Mediate Triage of Misfolded Membrane Proteins for Proteasomal versus Lysosomal Degradation

The endoplasmic reticulum (ER) fills the cell with a continuous network of sealed membrane tubules and sheets. The ER is subdivided into microdomains mediating one-third of total protein biosynthesis, oxidative protein folding, secretion, protein quality control, calcium signaling, marcoautophagy/autophagy, stress sensing, and apoptosis. Defects in ER-calcium homeostasis underlie several diseases. Damage to the ER by misfolded membrane proteins is suppressed by specific HSPA/Hsp70 and DNAJ/Hsp40 chaperone pairs that select intermediates for ubiquitination and ER-associated degradation (ERAD) via the proteasome. The ER-transmembrane Hsp40 chaperone DNAJB12 and HSPA/Hsp70 also target toxic intermediates of misfolded membrane proteins for ER-associated autophagy (ERAA). DNAJB12-HSPA/Hsp70 maintain membrane protein degradation intermediates in detergent-soluble and degradation-competent states. DNAJB12-HSPA/Hsp70 also interact with the autophagy initiation kinase ULK1 on ER tubules containing ERAD-resistant misfolded membrane proteins (ERAD-RMPs). Omegasomes are ER microdomains where the autophagosome precursor or phagophore (PG) forms. ER tubules loaded with ERAD-RMPs enter omegasomes where they are converted into ER-connected PG (ER-PG). The Atg8 (autophagy related 8)-family member GABARAP (GABA type A receptor-associated protein) facilitates transfer of ERAD-RMPs from ER-PGs to autolysosomes (AL) that dock transiently with omegasomes. This article describes a model for DNAJB12-HSPA/Hsp70 action during the conformation-dependent triage in the ER of misfolded membrane proteins for folding versus proteasomal or AL degradation.

P-OGC94 Outcomes of oesophagectomy post endoscopic mucosal resection

Background

Within developed nations, oesophageal adenocarcinoma has the greatest incidence of any solid organ tumour with number escalating on a yearly basis. A recent expert review by the AGA suggests that high grade Barrett’s dysplasia and intramucosal adenocarcinoma are better treated endoscopically rather than oesophagectomy and that endoscopic management is a reasonable alternative to oesophagectomy for selected patients with low risk pT1b tumours.. Risk factors for nodal involvement and recurrence have been suggested by Lee et al (1). This study aims to review the pathological and clinical outcomes following oesophagectomy post EMR.

Methods

Results

Conclusions

Whilst some low risk patients had residual tumour at oesophagectomy, these findings were similar to Nelson et al 3; recurrent/recurrent local tumour could be potentially managed by repeat EMR. The absence of nodal metastasis in this small series is consistent with the AGA recommendation of EMR as a reasonable alternative to oesophagectomy for patients with selected low risk pT1b tumors.

Postoperative outcomes in oesophagectomy with trainee involvement

BACKGROUND

The complexity of oesophageal surgery and the significant risk of morbidity necessitates that oesophagectomy is predominantly performed by a consultant surgeon, or a senior trainee under their supervision. The aim of this study was to determine the impact of trainee involvement in oesophagectomy on postoperative outcomes in an international multicentre setting.

METHODS

Data from the multicentre Oesophago-Gastric Anastomosis Study Group (OGAA) cohort study were analysed, which comprised prospectively collected data from patients undergoing oesophagectomy for oesophageal cancer between April 2018 and December 2018. Procedures were grouped by the level of trainee involvement, and univariable and multivariable analyses were performed to compare patient outcomes across groups.

RESULTS

Of 2232 oesophagectomies from 137 centres in 41 countries, trainees were involved in 29.1 per cent of them (n = 650), performing only the abdominal phase in 230, only the chest and/or neck phases in 130, and all phases in 315 procedures. For procedures with a chest anastomosis, those with trainee involvement had similar 90-day mortality, complication and reoperation rates to consultant-performed oesophagectomies (P = 0.451, P = 0.318, and P = 0.382, respectively), while anastomotic leak rates were significantly lower in the trainee groups (P = 0.030). Procedures with a neck anastomosis had equivalent complication, anastomotic leak, and reoperation rates (P = 0.150, P = 0.430, and P = 0.632, respectively) in trainee-involved versus consultant-performed oesophagectomies, with significantly lower 90-day mortality in the trainee groups (P = 0.005).

CONCLUSION

Trainee involvement was not found to be associated with significantly inferior postoperative outcomes for selected patients undergoing oesophagectomy. The results support continued supervised trainee involvement in oesophageal cancer surgery.

616 Rare KIT gene mutation in a recurrent GIST: Case Report

Introduction

The diagnosis and treatment of Gastro-intestinal stromal tumours (GISTs) has been revolutionized by molecular pathology and targeted therapy.

Description

This patient was diagnosed with locally advanced gastric GIST in 2009. He was initially treated neoadjuvantly with imatinib from 2009- 2010. He underwent laparoscopic resection in 2010. Pathology showed almost complete response with only 1.5mm focus of viable tumour. He did not receive adjuvant imatinib as this was not established practice in 2010. Recurrent disease was resected in 2011. Mitotic count was 200/50hpf. Adjuvant imatinib was given for 5 years then discontinued in 2016. Imaging showed no recurrence over this time period. Molecular testing showed Kit Exon 11 mutation- this is common in GISTs and associated with response to imatinib. Recurrent disease was diagnosed 2018 with a 10x9cm mass between residual stomach and liver– he recommenced imatinib with partial response (maximal response was reached in 2020, but a new 3cm lesion was noted) He underwent further resection of the residual stomach and liver segmentectomy in 2020. Histology showed acellular areas of myxoid degeneration, indicating treatment response however viable tumour remained. Sequencing was performed. This showed the expected mutation in exon 11 but also a mutation in exon 13 of KIT- this has been shown recently to confer resistance to imatinib.

Discussion

Over 90% of GISTs harbour mutations in c-KIT. Recent work has demonstrated that some tumours acquire secondary mutations conferring resistance, following prolonged TKI therapy. Radiological and histopathological features correlate with such events and assist in deciding surgical management.

Risk Prediction Model of 90-Day Mortality After Esophagectomy for Cancer

Importance

Ninety-day mortality rates after esophagectomy are an indicator of the quality of surgical oncologic management. Accurate risk prediction based on large data sets may aid patients and surgeons in making informed decisions.

Objective

To develop and validate a risk prediction model of death within 90 days after esophagectomy for cancer using the International Esodata Study Group (IESG) database, the largest existing prospective, multicenter cohort reporting standardized postoperative outcomes.

Design, Setting, and Participants

In this diagnostic/prognostic study, we performed a retrospective analysis of patients from 39 institutions in 19 countries between January 1, 2015, and December 31, 2019. Patients with esophageal cancer were randomly assigned to development and validation cohorts. A scoring system that predicted death within 90 days based on logistic regression β coefficients was conducted. A final prognostic score was determined and categorized into homogeneous risk groups that predicted death within 90 days. Calibration and discrimination tests were assessed between cohorts.

Exposures

Esophageal resection for cancer of the esophagus and gastroesophageal junction.

Main Outcomes and Measures

All-cause postoperative 90-day mortality.

Results

A total of 8403 patients (mean [SD] age, 63.6 [9.0] years; 6641 [79.0%] male) were included. The 30-day mortality rate was 2.0% (n = 164), and the 90-day mortality rate was 4.2% (n = 353). Development (n = 4172) and validation (n = 4231) cohorts were randomly assigned. The multiple logistic regression model identified 10 weighted point variables factored into the prognostic score: age, sex, body mass index, performance status, myocardial infarction, connective tissue disease, peripheral vascular disease, liver disease, neoadjuvant treatment, and hospital volume. The prognostic scores were categorized into 5 risk groups: very low risk (score, ≥1; 90-day mortality, 1.8%), low risk (score, 0; 90-day mortality, 3.0%), medium risk (score, -1 to -2; 90-day mortality, 5.8%), high risk (score, -3 to -4: 90-day mortality, 8.9%), and very high risk (score, ≤-5; 90-day mortality, 18.2%). The model was supported by nonsignificance in the Hosmer-Lemeshow test. The discrimination (area under the receiver operating characteristic curve) was 0.68 (95% CI, 0.64-0.72) in the development cohort and 0.64 (95% CI, 0.60-0.69) in the validation cohort.

Conclusions and Relevance

In this study, on the basis of preoperative variables, the IESG risk prediction model allowed stratification of an individual patient's risk of death within 90 days after esophagectomy. These data suggest that this model can help in the decision-making process when esophageal cancer surgery is being considered and in informed consent.

POS1497-PARE POST-TRIAL SURVEY OF PARTICIPANTS OF A PHASE 3 CLINICAL TRIAL IN SSC-ILD

Background:

The SENSCIS® trial (2015–18) was a large clinical trial (n=576) investigating the efficacy and safety of nintedanib in patients with systemic sclerosis-associated interstitial lung disease.1 The clinical research sponsors (CRS) collaborated with the scleroderma patient community advisory board (CAB) regarding the design, implementation and conduct of the trial.2 As part of this collaboration, the CRS and CAB developed a post-trial survey for SENSCIS® participants. The use of the developed patient-centric materials was optional for the sites.

Objectives:

The objectives of the SENSCIS® post-trial survey were to gain experience in collecting real-world information and trial satisfaction data from patients to inform and improve future patient centric clinical research.

Methods:

SENSCIS® trial participants who were involved in the extension trial SENSCIS®-ON completed a post-trial survey covering nine multiple-choice questions about three main topics:

[1]Recruitment – Where do patients usually search for clinical trials and how did they become aware of SENSCIS®?

[2]Motivation & Retention – What motivated patients to start and continue participation in SENSCIS®?

[3]Challenges & Wishes – What were the challenges during trial participation and how can future clinical trials be improved regarding patient centricity?

Results:

A total of 125 participants completed all survey questions. Participants could select more than one option. A total of 51 patients reported that they are usually not actively looking for trials. For those actively searching, the most common sources to learn about trials were specialists/general practitioners (GPs) (46 patients) and internet search engines (20 patients), followed by patient organisations (12 patients). Of note, 78 patients would pay attention to printed materials, such as a card/flyer/poster in a doctor’s office and get in touch with a trial/study site.

Back in 2015–2017, during recruitment for the SENSCIS® trial, the majority of the patients who answered the survey were made aware via their specialist/GP (116 patients), whereas 5 were made aware via patient organisations and 4 via the internet.

The most frequent motivations to join the trial were ‘hope to receive an improved therapy’ (98 patients), to help other patients (64 patients), and on the recommendation of their specialist/GP (81 patients). Similarly, the most liked aspects of the trial were the ‘opportunity to receive an improved therapy’ (92 patients) and ‘to support the development of an improved therapy for my illness’ (90 patients). More than half of patients reported ‘continuous observation of general health’ (72 patients) and ‘advice from GPs/specialists’ (71 patients) as motivation to stay in the trial (Figure 1).

‘Concerns about side effects’ (72 patients) and ‘not knowing whether the trial medication will work for me’ (63 patients) were reported as the least liked aspects of the trial. Travel to the site was reported as a challenge by 21 patients.

To improve clinical trials, patients requested more patient-friendly information (50 patients) and multiple formats of information material (46 patients). Finally, 48 patients expressed the desire to communicate with other trial participants.

Conclusion:

The SENSCIS® post-trial survey is a unique approach to receive real-world feedback from trial participants, and these pilot data will help improve future clinical trials and communication. The results highlight the importance of reaching patients who may not be actively looking for clinical trials.

Figure 1.

Motivation to stay in the SENSCIS® trial1,2

1More than one option could be selected.

2Data collected on 9th January 2021

References:

[1]Distler O et al. N Engl J Med. 2019 Jun 27;380(26):2518-2528. doi: 10.1056/NEJMoa1903076.

[2]Roennow A et al. BMJ Open. 2020 Dec 16;10(12):e039473. doi: 10.1136/bmjopen-2020-039473.

Acknowledgements:

Sue Farrington (Federation of European Scleroderma Associations [FESCA] Belgium), Luke Evnin (Scleroderma Research Foundation, United States), Beatriz Garcia (Asociacion Espanola de Esclerodermia, Spain), Catarina Leite (Associacao Portuguesa de Doentes com Esclerodermia, Portugal), Alison Zheng (Chinese Organisation for Scleroderma), Matea Perković Popović (Hrvatska udruga oboljelih od sklerodermije, Croatia), Tina Ampudia (Asociacion Mexicana de Orientacion Apoyo y Lucha Contra la Esclerodermia, AC, Mexico), Stephanie Munoz (Norsk Revmatikerforbund, Diagnosegruppen for Systemisk Sklerose, Norway), Monica Holmner (Reumatikerförbundet Riksföreningen för systemisk skleros, Sweden).

Disclosure of Interests:

Ilaria Galetti: None declared, EDITH BROWN: None declared, Ann Kennedy Consultant of: I have been a member of the CAB (Community Patient Advisory Board) described in the accompanying abstract under discussion. My patient organisation has been paid for its participation in the CAB., Grant/research support from: It is not myself personally, but FESCA (Federation of European Scleroderma Associations) aisbl., that has received project grants for awareness raising and education. I was President of this Federation., Robert J Riggs: None declared, Annelise Roennow: None declared, Maureen Sauvé: None declared, Joep Welling Speakers bureau: BI MIDI and BI International, Sanofi, Henrik Finnern Employee of: I am employee of Boehringer Ingelheim International GmbH, Annie Gilbert Consultant of: I am a paid consultant for Bohringer Ingelheim since 2016, Martina Gahlemann Employee of: I am employed by Boehringer Ingelheim (Schweiz) GmbH, Basel, Switzerland, Wiebke Sauter Employee of: I am employer of Boehringer-Ingelheim

Barriers to Comprehensive Multidisciplinary Head and Neck Care in a Community Oncology Practice

Complex, coordinated, and collaborative care of patients with head and neck cancer can be challenging yet amazingly rewarding and successful. The high symptom burden across multiple functional domains in patients with head and neck cancer, even in early stages of disease, mandates a multidisciplinary team approach that harnesses the combined contributions of physicians and ancillary providers to drive greater patient-centered care, addressing factors that heavily influence morbidity, mortality, and quality of life. Well-organized community-based multidisciplinary teams fulfill this unmet need and benefit patients with conveniently located comprehensive services that are typically found in large academic centers. Equivalent, if not superior, outcomes can be achieved in a unified community-based multidisciplinary team with shared patient-centered and outcomes-based goals. However, implementing true multidisciplinary team care in today's complex health care environment is fraught with challenges and pitfalls. So how have some community-based practices managed to create safe and efficient programs with successful outcomes? The purpose of this review is to discuss barriers to reaching this success and emphasize practical solutions to such challenges.

The Association Between Same-Sex Marriage Legalization and Youth Deaths by Suicide: A Multimethod Counterfactual Analysis

PURPOSE

To estimate the association between same-sex marriage legalization and deaths by suicide among youth.

METHODS

The study used country-level suicide data sourced from the Global Burden of Disease Study for all 36 Organisation for Economic Co-operation and Development countries for the period 1991-2017. We analyzed the suicide rates of all youth, male youth, and female youth aged 10-24 years using multiple policy-evaluation methods-difference-in-differences, matrix completion, and generalized synthetic control via expectation-maximization-to estimate the impact of same-sex marriage legalization at the country level. Secondary analysis considered several covariate specifications, evaluated the immediacy and persistence of the estimated associations, and assessed whether any observed association was limited to early adopters of same-sex marriage.

RESULTS

The state-of-the-art matrix completion analysis indicated that same-sex marriage legalization was associated with a decline in the youth suicide rate of 1.191 deaths per 100,000 individuals (95% CI = -1.66, -.64; p < .001), corresponding to a reduction of 17.90% compared to the youth suicide rate at the time of legalization. This decline was most pronounced in males for whom the suicide rate fell by 1.993 (CI = -2.76, -1.12; p < .001) compared to a decrease of .348 for female youth (CI = -.60, -.06; p = .02), corresponding to decreases of 19.98% and 10.90%, respectively. These associations persisted after legalization, but to differing degrees depending on model specification.

CONCLUSIONS

Developed countries that are yet to legalize same-sex marriage have an opportunity to put downward pressure on youth suicide.

Mortality from esophagectomy for esophageal cancer across low, middle, and high-income countries: An international cohort study

BACKGROUND

No evidence currently exists characterising global outcomes following major cancer surgery, including esophageal cancer. Therefore, this study aimed to characterise impact of high income countries (HIC) versus low and middle income countries (LMIC) on the outcomes following esophagectomy for esophageal cancer.

METHOD

This international multi-center prospective study across 137 hospitals in 41 countries included patients who underwent an esophagectomy for esophageal cancer, with 90-day follow-up. The main explanatory variable was country income, defined according to the World Bank Data classification. The primary outcome was 90-day postoperative mortality, and secondary outcomes were composite leaks (anastomotic leak or conduit necrosis) and major complications (Clavien-Dindo Grade III - V). Multivariable generalized estimating equation models were used to produce adjusted odds ratios (ORs) and 95% confidence intervals (CI95%).

RESULTS

Between April 2018 to December 2018, 2247 patients were included. Patients from HIC were more significantly older, with higher ASA grade, and more advanced tumors. Patients from LMIC had almost three-fold increase in 90-day mortality, compared to HIC (9.4% vs 3.7%, p < 0.001). On adjusted analysis, LMIC were independently associated with higher 90-day mortality (OR: 2.31, CI95%: 1.17-4.55, p = 0.015). However, LMIC were not independently associated with higher rates of anastomotic leaks (OR: 1.06, CI95%: 0.57-1.99, p = 0.9) or major complications (OR: 0.85, CI95%: 0.54-1.32, p = 0.5), compared to HIC.

CONCLUSION

Resections in LMIC were independently associated with higher 90-day postoperative mortality, likely reflecting a failure to rescue of these patients following esophagectomy, despite similar composite anastomotic leaks and major complication rates to HIC. These findings warrant further research, to identify potential issues and solutions to improve global outcomes following esophagectomy for cancer.

Community prevalence, mechanisms and outcome of mitral or tricuspid regurgitation

OBJECTIVE

The study aims were (1) to identify the community prevalence of moderate or greater mitral or tricuspid regurgitation (MR/TR), (2) to compare subjects identified by population screening with those with known valvular heart disease (VHD), (3) to understand the mechanisms of MR/TR and (4) to assess the rate of valve intervention and long-term outcome.

METHODS

Adults aged ≥65 years registered at seven family medicine practices in Oxfordshire, UK were screened for inclusion (n=9504). Subjects with known VHD were identified from hospital records and those without VHD invited to undergo transthoracic echocardiography (TTE) within the Oxford Valvular Heart Disease Population Study (OxVALVE). The study population ultimately comprised 4755 subjects. The severity and aetiology of MR and TR were assessed by integrated comprehensive TTE assessment.

RESULTS

The prevalence of moderate or greater MR and TR was 3.5% (95% CI 3.1 to 3.8) and 2.6% (95% CI 2.3 to 2.9), respectively. Primary MR was the most common aetiology (124/203, 61.1%). Almost half of cases were newly diagnosed by screening: MR 98/203 (48.3%), TR 69/155 (44.5%). Subjects diagnosed by screening were less symptomatic, more likely to have primary MR and had a lower incidence of aortic valve disease. Surgical intervention was undertaken in six subjects (2.4%) over a median follow-up of 64 months. Five-year survival was 79.8% in subjects with isolated MR, 84.8% in those with isolated TR, and 59.4% in those with combined MR and TR (p=0.0005).

CONCLUSIONS

Moderate or greater MR/TR is common, age-dependent and is underdiagnosed. Current rates of valve intervention are extremely low.

International recommendations for personalised selective internal radiation therapy of primary and metastatic liver diseases with yttrium-90 resin microspheres

PURPOSE

A multidisciplinary expert panel convened to formulate state-of-the-art recommendations for optimisation of selective internal radiation therapy (SIRT) with yttrium-90 (90Y)-resin microspheres.

METHODS

A steering committee of 23 international experts representing all participating specialties formulated recommendations for SIRT with 90Y-resin microspheres activity prescription and post-treatment dosimetry, based on literature searches and the responses to a 61-question survey that was completed by 43 leading experts (including the steering committee members). The survey was validated by the steering committee and completed anonymously. In a face-to-face meeting, the results of the survey were presented and discussed. Recommendations were derived and level of agreement defined (strong agreement ≥ 80%, moderate agreement 50%-79%, no agreement ≤ 49%).

RESULTS

Forty-seven recommendations were established, including guidance such as a multidisciplinary team should define treatment strategy and therapeutic intent (strong agreement); 3D imaging with CT and an angiography with cone-beam-CT, if available, and 99mTc-MAA SPECT/CT are recommended for extrahepatic/intrahepatic deposition assessment, treatment field definition and calculation of the 90Y-resin microspheres activity needed (moderate/strong agreement). A personalised approach, using dosimetry (partition model and/or voxel-based) is recommended for activity prescription, when either whole liver or selective, non-ablative or ablative SIRT is planned (strong agreement). A mean absorbed dose to non-tumoural liver of 40 Gy or less is considered safe (strong agreement). A minimum mean target-absorbed dose to tumour of 100-120 Gy is recommended for hepatocellular carcinoma, liver metastatic colorectal cancer and cholangiocarcinoma (moderate/strong agreement). Post-SIRT imaging for treatment verification with 90Y-PET/CT is recommended (strong agreement). Post-SIRT dosimetry is also recommended (strong agreement).

CONCLUSION

Practitioners are encouraged to work towards adoption of these recommendations.

Incidence and risk factors for sustained hepatic function toxicity 6 months after radioembolization: analysis of the radiation-emitting sir-spheres in non-resectable liver tumor (RESIN) registry

Background

To quantify rates and risk factors for toxicity after hepatic radioembolization using resin yttrium-90 microspheres.

Methods

Radiation-Emitting SIR-Spheres in Non-resectable liver tumor (RESIN) registry enrollees were reviewed with 614 patients included. Mean patient age was 63.1±12.5 years. The majority of patients were male (n=375, 61%) and white (n=490, 80%). Common tumor types were hepatocellular (n=197, 32%), colorectal (n=187, 30%) and neuroendocrine (n=56, 9%). Hepatotoxicity was measured using the Common Terminology Criteria for Adverse Events (CTCAE v 5). Potential risk factors for hepatotoxicity were tested using the Kruskal-Wallis or Pearson Chi-squared tests, and multivariate linear regressions.

Results

At 6 months, 115 patients (18.7%) died (n=91, 14.8%), entered hospice (n=20, 3.3%) or sought treatment elsewhere (n=4, 4%). Seven (1.1%) deaths were from liver decompensation. Grade 3 toxicity rates were: bilirubin (n=85, 13.8%), albumin (n=28, 4.6%), ALT (n=26, 4.2%) and AST (n=37, 6.0%). For each of these liver function test components, baseline abnormal labs predicted Grade 3 toxicity at follow-up by Kruskal-Wallis test (P<0.001) and linear regression (all P<0.03). Other significant factors predicting toxicity at regression included elevated Body-Mass Index (albumin P=0.0056), whole liver treatment (bilirubin P=0.046), and lower tumor volume (ALT and INR, P<0.035 for both).

Conclusions

Baseline liver function abnormalities prior to radioembolization is the strongest predictor of post-treatment Grade 3 toxicity with rates as high as 13.8%. Toxicity rates for specific lab values are affected by large volume treatments especially with low tumor volumes.

Standard versus hypofractionated intensity-modulated radiotherapy for prostate cancer: assessing the impact on dose modulation and normal tissue effects when using patient-specific cancer biology

Hypofractionation of prostate cancer radiotherapy achieves tumour control at lower total radiation doses, however, increased rectal and bladder toxicities have been observed. To realise the radiobiological advantage of hypofractionation whilst minimising harm, the potential reduction in dose to organs at risk was investigated for biofocused radiotherapy. Patient-specific tumour location and cell density information were derived from multiparametric imaging. Uniform-dose plans and biologically-optimised plans were generated for a standard schedule (78 Gy/39 fractions) and hypofractionated schedules (60 Gy/20 fractions and 36.25 Gy/5 fractions). Results showed that biologically-optimised plans yielded statistically lower doses to the rectum and bladder compared to isoeffective uniform-dose plans for all fractionation schedules. A reduction in the number of fractions increased the target dose modulation required to achieve equal tumour control. On average, biologically-optimised, moderately-hypofractionated plans demonstrated 15.3% (p-value: <0.01) and 23.8% (p-value: 0.02) reduction in rectal and bladder dose compared with standard fractionation. The tissue-sparing effect was more pronounced in extreme hypofractionation with mean reduction in rectal and bladder dose of 43.3% (p-value: < 0.01) and 41.8% (p-value: 0.02), respectively. This study suggests that the ability to utilise patient-specific tumour biology information will provide greater incentive to employ hypofractionation in the treatment of localised prostate cancer with radiotherapy. However, to exploit the radiobiological advantages given by hypofractionation, greater attention to geometric accuracy is required due to increased sensitivity to treatment uncertainties.

Critical Appraisal of the Impact of Oesophageal Stents in the Management of Oesophageal Anastomotic Leaks and Benign Oesophageal Perforations: An Updated Systematic Review

INTRODUCTION

Endoscopic placement of oesophageal stents may be used in benign oesophageal perforation and oesophageal anastomotic leakage to control sepsis and reduce mortality and morbidity by avoiding thoracotomy. This updated systematic review aimed to assess the safety and effectiveness of oesophageal stents in these two scenarios.

METHODS

A systematic literature search of all published studies reporting use of metallic and plastic stents in the management of post-operative anastomotic leaks, spontaneous and iatrogenic oesophageal perforations were identified. Primary outcomes were technical (deploying ≥ 1 stent to occlude site of leakage with no evidence of leakage of contrast within 24-48 h) and clinical success (complete healing of perforation or leakage by placement of single or multiple stents irrespective of whether the stent was left in situ or was removed). Secondary outcomes were stent migration, perforation and erosion, and mortality rates. Subgroup analysis was performed for plastic versus metallic stents and anastomotic leaks versus perforations separately.

RESULTS

A total of 66 studies (n = 1752 patients) were included. Technical and clinical success rates were 96% and 87%, respectively. Plastic stents had significantly higher migration rates (24% vs 16%, p = 0.001) and repositioning (11% vs 3%, p < 0.001) and lower technical success (91% vs 95%, p = 0.032) than metallic stents. In patients with anastomotic leaks, plastic stents were associated with higher stent migration (26% vs 15%, p = 0.034), perforation (2% vs 0%, p = 0.013), repositioning (10% vs 0%, p < 0.001), and lower technical success (95% vs 100%, p = p = 0.002). In patients with perforations only, plastic stents were associated with significantly lower technical success (85% vs 99%, p < 0.001).

CONCLUSIONS

Covered metallic oesophageal stents appear to be more effective than plastic stents in the management of oesophageal perforation and anastomotic leakage. However, quality of evidence of generally poor and high-quality randomised trial is needed to further evaluate best management option for oesophageal perforation and anastomotic leakage.

Stereotactic Inverse Dose Planning After Yttrium-90 Selective Internal Radiation Therapy in Hepatocellular Cancer

Purpose

Selective internal radiation therapy (SIRT) is administered to treat tumors of the liver and is generally well tolerated. Although widely adopted for its therapeutic benefits, SIRT is rarely combined with external beam radiation therapy (EBRT) owing to the complexity of the dosimetry resulting from the combination of treatments with distinct radiobiological effects. The purpose of this study was to establish a dosimetric framework for combining SIRT and EBRT using clinical experience derived from representative patients with hepatocellular carcinoma (HCC) who received both therapies.

Methods and Materials

Treatments from 10 patients with HCC given EBRT either before or after SIRT were analyzed. The dosimetry framework used here considered differences in the radiobiological effects and fractionation schemes of SIRT versus EBRT, making use of the concepts of biological effective dose (BED) and equivalent dose (EQD). Absorbed dose from SIRT was calculated, converted to BED, and summed with BED from EBRT dose plans. Two of these patients were used in a virtual planning exercise to investigate the feasibility of combining stereotactic body radiation therapy and SIRT.

Results

The combination of EBRT and SIRT in 10 patients with HCC showed no major toxicity. No Child-Pugh scores went above 8 and albumin-bilirubin scores from only 1 patient worsened to grade 3 (> -1.39) from treatment through 3-months follow-up. A framework with radiobiological modeling was developed to manage the combined treatments in terms of their sum BED. The exploratory SIRT plus SABR inverse dose plans for 2 patients, incorporating radiobiologically informed ⁹⁰Y SIRT dosimetry, achieved dose distributions comparable to SBRT alone.

Conclusions

Treatment with both EBRT and SIRT can be given safely to patients with HCC. The BED and EQD concepts should be used in combined dosimetry to account for the differing radiobiological effects of EBRT and SIRT. Inverse dose planning of EBRT after SIRT could provide improved dose distributions and flexibility to the clinical workflow. Further research into combination therapy is needed through prospective trials.

Have whales returned to a historical hotspot of industrial whaling? The pattern of southern right whale Eubalaena australis recovery at South Georgia

Around 176500 whales were killed in the sub-Antarctic waters off South Georgia (South Atlantic) between 1904 and 1965. In recent decades, whales have once again become summer visitors, with the southern right whale (SRW) the most commonly reported species until 2011. Here, we assess the distribution, temporal pattern, health status and likely prey of SRWs in these waters, combining observations from a summertime vessel-based expedition to South Georgia, stable isotope data collected from SRWs and putative prey and sightings reports collated by the South Georgia Museum. The expedition used directional acoustics and visual surveys to localise whales and collected skin biopsies and photo-IDs. During 76 h of visual observation effort over 19 expedition days, SRWs were encountered 15 times (~31 individuals). Photo-IDs, combined with publicly contributed images from commercial vessels, were reconciled and quality-controlled to form a catalogue of 6 fully (i.e. both sides) identified SRWs and 26 SRWs identified by either left or right sides. No photo-ID matches were found with lower-latitude calving grounds, but 3 whales had gull lesions supporting a direct link with Península Valdés, Argentina. The isotopic position of SRWs in the South Georgia food web suggests feeding on a combination of copepod and krill species. Opportunistic reports of SRW sightings and associated group sizes remain steady over time, while humpback whales provide a strong contrast, with increased sighting rates and group sizes seen since 2013. These data suggest a plateau in SRWs and an increasing humpback whale presence in South Georgia waters following the cessation of whaling.