The impact of postoperative radiological surveillance intensity on disease free and overall survival from primary retroperitoneal, abdominal and pelvic soft-tissue sarcoma

AIM

This observational study aimed to evaluate the impact of intensity of radiological surveillance on survival following resection of retroperitoneal sarcoma.

METHOD

Retrospective cohort study of patients undergoing primary resection of soft tissue sarcoma arising in the retroperitoneum, abdomen or pelvis at a single, high-volume sarcoma centre. Intensity of follow-up regimes up to 5 postoperative years were categorized as 'European Society for Medical Oncology (ESMO) compliant' (intense), or 'non-ESMO compliant' (less-intense). The primary outcome measure was overall survival (OS). The secondary outcome measures were disease-free survival (DFS) and reoperation rate. Analyses were stratified by high (grade 2 or 3) or low (grade 1) tumour grade.

RESULTS

Of 168 patients, 67.1% had high-grade and 32.9% had low-grade disease. Overall, 40.0% of patients had ESMO-compliant radiological follow-up (high-grade:25.7%, low-grade:66.7%). 41.7% of patients died and 48.2% suffered local or distant recurrence by cessation of follow up. Upon univariable analysis for high-grade tumours, ESMO compliance reduced DFS (p = 0.066) but had no impact on OS. There was no significant difference in the reoperation rate in patients with ESMO-compliant and non-compliant follow-up (p = 0.097). In low-grade tumours, ESMO compliance significantly reduced DFS (p < 0.001), but without effecting OS. In risk-adjusted models for high-grade tumours, ESMO compliant follow-up was associated with reduced OS (HR:3.47, 1.40-8.61, p = 0.007) and no difference in DFS. In low-grade tumours, there was no association between overall ESMO compliance and OS or DFS.

CONCLUSION

This study did not find a benefit for high-intensity radiological surveillance and overall survival in patients undergoing primary resection for high or low-grade retroperitoneal sarcoma.

Intercontinental collaborative experience with abdominal, retroperitoneal and pelvic schwannomas

Background

Schwannomas are rare tumours that pose a significant management challenge in the abdomen, retroperitoneum and pelvis. No data are available to inform management strategy.

Methods

A collaborative international cohort study, across specialist sarcoma units, was conducted to include adults presenting between 2000 and 2017 with histopathologically confirmed schwannomas within the abdomen, retroperitoneum or pelvis.

Results

Of 485 patients across 12 centres, 38 (7·8 per cent) were discharged without follow-up, 199 (41·0 per cent) underwent early resection and 248 (51·1 per cent) had radiological monitoring. Of these 248 patients, 96 (38·7 per cent) eventually had surgery, giving an overall resection rate of 60·8 per cent (295 of 485). At baseline, median tumour volume was 90·1 (i.q.r. 26·5–262·0) cm3. The estimated growth rate was 10·5 (95 per cent c.i. 9·4 to 11·6) per cent per year, and was consistent in the short term (within 2 years of diagnosis) and long term (beyond 2 years) (ρ = 0·405, P = 0·021). A decision to operate was more common in symptomatic patients (P &lt; 0·001) and for rapidly growing tumours (growth rate more than 20 per cent per year) (P = 0·025). R0/R1 resection was achieved in 91·6 per cent of patients (263 of 287). Kaplan–Meier long-term recurrence rates after R0/R1 resection were 2·3 and 6·7 per cent at 3 and 5 years respectively.

Conclusion

Specific recommendations include: indications for early surgery, prediction of growth from radiological monitoring, promotion of selective submacroscopic resection and cessation of postoperative imaging surveillance.

Diagnostic accuracy of percutaneous biopsy in retroperitoneal sarcoma

Background

Percutaneous biopsy is recommended before surgery for suspected retroperitoneal sarcoma (RPS) to confirm the histological diagnosis and guide surgical strategy. The present study aimed to establish the diagnostic accuracy of percutaneous core biopsy with respect to histological diagnosis and tumour grade.

Methods

Data on patients with suspected RPS who underwent percutaneous biopsy followed by surgical resection between 2005 and 2016 at one of two tertiary European sarcoma units were reviewed. Histological tumour type and tumour grade on biopsy were correlated with postoperative histology to evaluate diagnostic accuracy.

Results

A total of 239 patients underwent percutaneous core biopsy followed by surgical resection in Milan (163, 68·2 per cent) or Birmingham (76, 31·8 per cent). Diagnostic accuracy varied with histological diagnosis (P &lt; 0·001), but demonstrated overall concordance with final pathology following resection in 67·2 per cent of biopsies (κ = 0·606). The majority of discrepancies occurred in dedifferentiated liposarcoma (DDLPS), owing to under-recognition of dedifferentiation in this group. Concordance between pathology on biopsy and resection improved to 81·1 per cent when DDLPS and well differentiated liposarcoma were grouped together as liposarcoma. Grade on biopsy was concordant with grade on resection specimen in 60·4 per cent of tumours (κ = 0·640). Diagnosis of high-grade tumours on biopsy had a high specificity (98 per cent), and moderate positive predictive value (85 per cent) and negative predictive value (78 per cent).

Conclusion

A diagnosis of DDLPS or leiomyosarcoma on percutaneous biopsy is highly reliable. High-grade sarcomas can be identified with high specificity, which opens the door to a study on neoadjuvant therapy in these patients.

Rapid infrared mapping for highly accurate automated histology in Barrett's oesophagus

Barrett's oesophagus (BE) is a premalignant condition that can progress to oesophageal adenocarcinoma. Endoscopic surveillance aims to identify potential progression at an early, treatable stage, but generates large numbers of tissue biopsies. Fourier transform infrared (FTIR) mapping was used to develop an automated histology tool for detection of BE and Barrett's neoplasia in tissue biopsies. 22 oesophageal tissue samples were collected from 19 patients. Contiguous frozen tissue sections were taken for pathology review and FTIR imaging. 45 mid-IR images were measured on an Agilent 620 FTIR microscope with an Agilent 670 spectrometer. Each image covering a 140 μm × 140 μm region was measured in 5 minutes, using a 1.1 μm² pixel size and 64 scans per pixel. Principal component fed linear discriminant analysis was used to build classification models based on spectral differences, which were then tested using leave-one-sample-out cross validation. Key biochemical differences were identified by their spectral signatures: high glycogen content was seen in normal squamous (NSQ) tissue, high glycoprotein content was observed in glandular BE tissue, and high DNA content in dysplasia/adenocarcinoma samples. Classification of normal squamous samples versus 'abnormal' samples (any stage of Barrett's) was performed with 100% sensitivity and specificity. Neoplastic Barrett's (dysplasia or adenocarcinoma) was identified with 95.6% sensitivity and 86.4% specificity. Highly accurate pathology classification can be achieved with FTIR measurement of frozen tissue sections in a clinically applicable timeframe.

Gastrointestinal manifestations of extramedullary plasmacytoma: a narrative review and illustrative case reports

Introduction Solitary extramedullary plasmacytoma are rare, solid-mass tumours which appear immunophenotypically similar to multiple myeloma. The diagnosis and management of gastrointestinal plasmacytoma is complex and requires multidisciplinary input. This study presents a narrative review of intra-abdominal extramedullary plasmacytoma, illustrated with two case studies. Methods The PubMed database was searched without date restrictions for reports of intra-abdominal extramedullary plasmacytoma to synthesise a narrative review. Electronic records were reviewed at a high-volume, quaternary soft-tissue sarcoma centre to identify patients with histopathologically confirmed extramedullary plasmacytoma affecting the gastrointestinal tract. Results Gastrointestinal extramedullary plasmacytomas can present with mass effect or organ-specific dysfunction. Techniques for tissue diagnosis of extramedullary plasmacytoma vary dependent on location, with a formal diagnosis often being made from a resected specimen. Management can include surgery, radiotherapy, systemic chemotherapy or a combination. No high-quality evidence base exists to guide treatment. Two case studies of operated gastrointestinal extramedullary plasmacytoma are presented at different phases of disease progression, with a resultant impact on survival. Conclusion Intra-abdominal extramedullary plasmacytoma is a rare and heterogeneous condition that lacks consensus guidelines for diagnosis and management. Collaboration between international specialist centres will create better quality evidence for treatment of this cohort.

Towards a Best Practice Approach in PBPK Modeling: Case Example of Developing a Unified Efavirenz Model Accounting for Induction of CYPs 3A4 and 2B6

In this study, we present efavirenz physiologically based pharmacokinetic (PBPK) model development as an example of our best practice approach that uses a stepwise approach to verify the different components of the model. First, a PBPK model for efavirenz incorporating in vitro and clinical pharmacokinetic (PK) data was developed to predict exposure following multiple dosing (600 mg q.d.). Alfentanil i.v. and p.o. drug‐drug interaction (DDI) studies were utilized to evaluate and refine the CYP3A4 induction component in the liver and gut. Next, independent DDI studies with substrates of CYP3A4 (maraviroc, atazanavir, and clarithromycin) and CYP2B6 (bupropion) verified the induction components of the model (area under the curve [AUC] ratios within 1.0–1.7‐fold of observed). Finally, the model was refined to incorporate the fractional contribution of enzymes, including CYP2B6, propagating autoinduction into the model (Racc 1.7 vs. 1.7 observed). This validated mechanistic model can now be applied in clinical pharmacology studies to prospectively assess both the victim and perpetrator DDI potential of efavirenz.

Metformin and cimetidine: Physiologically based pharmacokinetic modelling to investigate transporter mediated drug-drug interactions

Metformin is used as a probe for OCT2 mediated transport when investigating possible DDIs with new chemical entities. The aim of the current study was to investigate the ability of physiologically-based pharmacokinetic (PBPK) models to simulate the effects of OCT and MATE inhibition by cimetidine on metformin kinetics. PBPK models were developed, incorporating mechanistic kidney and liver sub-models for metformin (OCT and MATE substrate) and a mechanistic kidney sub-model for cimetidine. The models were used to simulate inhibition of the MATE1, MATE2-K, OCT1 and OCT2 mediated transport of metformin by cimetidine. Assuming competitive inhibition and using cimetidine Ki values determined in vitro, the predicted metformin AUC ratio was 1.0 compared to an observed value of 1.46. The observed AUC ratio could only be recovered with this model when the cimetidine Ki for OCT2 was decreased 1000-fold or the Ki's for both OCT1 and OCT2 were decreased 500-fold. An alternative description of metformin renal transport by OCT1 and OCT2, incorporating electrochemical modulation of the rate of metformin uptake together with 8-18-fold decreases in cimetidine Ki's for OCTs and MATEs, allowed recovery of the extent of the observed effect of cimetidine on metformin AUC. While the final PBPK model has limitations, it demonstrates the benefit of allowing for the complexities of passive permeability combined with active cellular uptake modulated by an electrochemical gradient and active efflux.

Development of a Multicompartment Permeability-Limited Lung PBPK Model and Its Application in Predicting Pulmonary Pharmacokinetics of Antituberculosis Drugs

Achieving sufficient concentrations of antituberculosis (TB) drugs in pulmonary tissue at the optimum time is still a challenge in developing therapeutic regimens for TB. A physiologically based pharmacokinetic model incorporating a multicompartment permeability-limited lung model was developed and used to simulate plasma and pulmonary concentrations of seven drugs. Passive permeability of drugs within the lung was predicted using an in vitro-in vivo extrapolation approach. Simulated epithelial lining fluid (ELF):plasma concentration ratios showed reasonable agreement with observed clinical data for rifampicin, isoniazid, ethambutol, and erythromycin. For clarithromycin, itraconazole and pyrazinamide the observed ELF:plasma ratios were significantly underpredicted. Sensitivity analyses showed that changing ELF pH or introducing efflux transporter activity between lung tissue and ELF can alter the ELF:plasma concentration ratios. The described model has shown utility in predicting the lung pharmacokinetics of anti-TB drugs and provides a framework for predicting pulmonary concentrations of novel anti-TB drugs.

Barrett's oesophagus: how should we manage it?

Endoscopic surveillance remains the core management of non-dysplastic Barrett's oesophagus, although questions regarding its efficacy in reducing mortality from oesophageal adenocarcinoma have yet to be definitively answered, and randomised trial data are awaited. One of the main goals of current research is to achieve risk stratification, identifying those at high risk of progression. The recent British Society of Gastroenterology (BSG) guidelines on surveillance have taken a step in this direction with interval stratification on clinicopathological grounds. The majority of Barrett's oesophagus remains undiagnosed, and this has led to investigation of methods of screening for Barrett's oesophagus, ideally non-endoscopic methods capable of reliably identifying dysplasia. Chemoprevention to prevent progression is currently under investigation, and may become a key component of future treatment. The availability of effective endotherapy means that accurate identification of dysplasia is more important than ever. There is now evidence to support intervention with radiofrequency ablation (RFA) for low-grade dysplasia (LGD), but recent data have emphasised the need for consensus pathology for LGD. Ablative treatment has become well established for high-grade dysplasia, and should be employed for flat lesions where there is no visible abnormality. Of the ablative modalities, RFA has the strongest evidence base. Endoscopic resection should be performed for all visible lesions, and is now the treatment of choice for T1a tumours. Targeting those with high-risk disease will, hopefully, lead to efficacious and cost-effective surveillance, and the trend towards earlier intervention to halt progression gives cause for optimism that this will ultimately result in fewer deaths from oesophageal adenocarcinoma.

Prediction of Metabolic Interactions With Oxycodone via CYP2D6 and CYP3A Inhibition Using a Physiologically Based Pharmacokinetic Model

Evaluation of a potential risk of metabolic drug–drug interactions (DDI) is of high importance in the clinical setting. In this study, a physiologically based pharmacokinetic (PBPK) model was developed for oxycodone and its two primary metabolites, oxymorphone and noroxycodone, in order to assess different DDI scenarios using published in vitro and in vivo data. Once developed and refined, the model was able to simulate pharmacokinetics of the three compounds and the DDI extent in case of coadministration with an inhibitor, as well as the oxymorphone concentration variation between CYP2D6 extensive metabolizers (EM) and poor metabolizers (PM). The reliability of the model was tested against published clinical studies monitoring different inhibitors and dose regimens, and all predicted area under the concentration–time curve (AUC) ratios were within the twofold acceptance range. This approach represents a strategy to evaluate the impact of coadministration of different CYP inhibitors using mechanistic incorporation of drug-dependent and system-dependent available in vitro and in vivo data.

Endoscopic resection with or without mucosal ablation of high grade dysplasia and early oesophageal adenocarcinoma--long term follow up from a regional UK centre

BACKGROUND

Endoscopic resection (ER) is emerging as a curative technique in patients with high-grade dysplasia (HGD), intramucosal cancer (IMC), and early submucosal cancer (T1sm1) within Barrett's oesophagus.

METHODS

This consecutive case series of 72 patients with HGD or IMC reports outcomes of ER, with or without mucosal ablation, in a single institution after a median of 38 months follow-up between 2004 and 2011. The primary outcome was disease progression to submucosal invasion. Secondary outcomes included disease regression, the effect of ER on staging compared to biopsy and procedure-related complications.

RESULTS

72 patients (mean age 73.0 - range 52.0-93.0) were treated by ER ± ablative therapy with curative intent for HGD (88% patients) or IMC (12%). 38% had one or more severe systemic co-morbidities. A median of 4 (1-11) procedures were undertaken per patient. In addition to ER, 43% of patients were treated with argon plasma coagulation, 17% with radiofrequency ablation, and 11% with photodynamic therapy. 8 (13%) patients with HGD at baseline and 0 (0%) with IMC progressed to invasive carcinoma. The median time to progression was 26.3 and 12.6 months respectively. 51% patients experienced disease regression. Disease staging was upgraded by ER in 27% of patients.

DISCUSSION

This case series reports on a minimally invasive technique in an elderly population with multiple co-morbidities, demonstrating disease regression with long-term follow-up.

CONCLUSION

ER ± ablation is an effective and potentially curative option for patients with HGD or IMC. The benefit of endoscopic resection for disease staging was clearly demonstrated.

Meta-analysis of endoscopic therapy for low-grade dysplasia in Barrett's oesophagus

Background

The optimal management of patients with Barrett's-associated low-grade dysplasia (LGD) is unclear. The objective of this study was to identify systematically all reports of endoscopic treatment of LGD, and to assess outcomes in terms of disease progression, eradication of dysplasia and intestinal metaplasia, and complication rates.

Methods

A systematic review of articles reporting endoscopic treatment of LGD was conducted in accordance with PRISMA guidelines. MEDLINE and Embase databases were searched to identify the relevant literature. Rates of complete eradication of intestinal metaplasia (CE-IM) and dysplasia (CE-D) were reported. The pooled incidence of progression to cancer was calculated following endoscopic therapy.

Results

Thirty-seven studies met the inclusion criteria, reporting outcomes of endoscopic therapy for 521 patients with LGD. The pooled incidence of progression to cancer was 3·90 (95 per cent confidence interval (c.i.) 1·27 to 9·10) per 1000 patient-years. CE-IM and CE-D were achieved in 67·8 (95 per cent c.i. 50·2 to 81·5) and 88·9 (83·9 to 92·5) per cent of patients respectively. The commonest adverse event was stricture formation.

Conclusion

Reports of endoscopic therapy were heterogeneous and follow-up periods were short. There is a high likelihood of historical overdiagnosis of LGD. Endoscopic therapy, particularly radiofrequency ablation, appears safe and effective at eradicating LGD, but does not eliminate the risk of progression to cancer.

Postcholecystectomy syndrome (PCS)

The term postcholecystectomy syndrome (PCS) comprises a heterogeneous group of symptoms and findings in patients who have previously undergone cholecystectomy. Although rare, these patients may present with abdominal pain, jaundice or dyspeptic symptoms. Many of these complaints can be attributed to complications including bile duct injury, biliary leak, biliary fistula and retained bile duct stones. Late sequelae include recurrent bile duct stones and bile duct strictures. With the number of cholecystectomies being performed increasing in the laparoscopic era the number of patients presenting with PCS is also likely to increase. We briefly explore the syndrome and its main aetiological theories.

Towards a quantitative framework for the prediction of DDIs arising from cytochrome P450 induction

Although CYP induction is not generally considered to be as clinically relevant as CYP inhibition, there are important examples where induction has caused both therapeutic failure, due to insufficient exposure to parent drug, and toxicity, mediated by increased formation of reactive metabolites. Furthermore, while there has been considerable progress in the extrapolation of in vitro data to predict the in vivo consequences of enzyme inhibition, less attention has been given to the quantitative impact of enzyme induction as a mechanism of drug-drug interaction (DDI) and as a component of compound selection and early drug development. We discuss current approaches in the context of a mechanistic framework for the prediction of the extent and time-course of enzyme induction in vivo based on in vitro experimentation. Factors influencing the extent of DDI due to CYP induction are summarised, and areas deficient in information that would allow more accurate prediction within target populations are highlighted.

Thoracic intradural disc herniation

Intradural disc herniation is a well-recognized entity in the lumbar region, where over 90% of all intradural herniations are seen.1 By contrast, fewer than 5% occur in either the cervical or thoracic regions.1 We describe a case of a sudden onset neurological deficit caused by an intradural thoracic disc herniation at the T11-T12 level, the intradural nature of which was not diagnosed on preoperative MRI. To the best of our knowledge this is the first description of an intradural disc herniation at this level.

Osteoporosis and determinants of bone density in patients with Crohn's disease

Low bone mineral density (BMD) is common in patients with Crohn's disease; however, the pathogenesis of bone loss and risk factors for osteoporosis are not established. Our aim was to evaluate the clinical, dietary, and nutritional determinants of BMD in Crohn's disease. A cross-sectional analysis of 117 patients with Crohn's disease was undertaken. All patients underwent a clinical and dietary evaluation including assessment of nutritional state and life-style. BMD was measured at the hip and lumbar spine by dual-energy x-ray absorptiometry; and z scores obtained by comparison with age- and sex-matched normal values for the healthy UK population. Multiple regression analysis was used to assess associations between BMD and potential risk factors, allowing for possible confounding variables. Thirteen (11%) patients had osteoporosis (z score < -2), with osteopenia (z score < -1, > -2) in a further 34 (29%). Patients with jejunal disease had significantly lower BMD at the spine (P = 0.03) and femoral neck (P = 0.02) than those with disease at other sites. Mean BMD was significantly lower at the hip of patients with previous bowel resection (diff in means = 0.53, 95% CI -0.97, -0.08, P = 0.02), but type of surgery was not significant. Active disease, menstrual history, diet, level of physical activity, and smoking were not associated with low bone mass. At the lumbar spine, body weight (P < 0.0001), male sex (P < 0.0001), and current prednisolone use (P < 0.02) were independently predictive of low bone mass. Body weight (P < 0.0001), male sex (P < 0.0001), and cumulative steroid dose (P = 0.02) were predictive at the femoral neck. The major determinants of BMD in Crohn's disease are body weight, current steroid use, and cumulative steroid dose. Men with Crohn's disease are at greatest risk of osteoporosis, with jejunal involvement and previous bowel resection also contributing to the low bone mineral density.

Effect of a low-impact exercise program on bone mineral density in Crohn's disease: a randomized controlled trial

BACKGROUND & AIMS

Physical exercise increases bone mineral density (BMD) in healthy young adults and slows the rate of bone loss in later life. The aim of this randomized controlled trial was to investigate the effect of exercise on BMD in patients with Crohn's disease.

METHODS

A total of 117 patients with Crohn's disease were randomized to a control group or a low-impact exercise program of increasing intensity. BMD (g/cm2) was measured at baseline and 12 months at the hip and spine (L2-L4) by dual energy x-ray absorptiometry.

RESULTS

Nonsignificant gains in BMD occurred at the hip and spine in the exercise group compared with controls (P > 0.05). In fully compliant patients, BMD increased by 3.54% (7.95%) at the femoral neck, 2.97% (7.7%) at the spine, 4.1% (10.26%) at Ward's triangle, and 7.77% (8.2%) at the greater trochanter. Compared with controls, gain in BMD at the greater trochanter was statistically significant (difference in means, 4.67; 95% confidence interval, 0.86-8.48; P = 0.02). Increases in BMD were significantly related to the number of exercise sessions completed (femoral neck; r = 0.28; 95% confidence interval, 0.10-0.45; P = 0.04).

CONCLUSIONS

Progressive low-impact exercise is a potentially effective method of increasing BMD in Crohn's disease. If sustained, the increases in BMD may reduce the risk of osteoporotic fracture.