Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

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.

Research quality and transparency, outcome measurement and evidence for safety and effectiveness in robot-assisted surgery: systematic review

BACKGROUND

Robot-assisted surgery (RAS) has potential panspecialty surgical benefits. High-quality evidence for widespread implementation is lacking. This systematic review aimed to assess the RAS evidence base for the quality of randomized evidence on safety and effectiveness, specialty 'clustering', and outcomes for RAS research.

METHODS

A systematic review was undertaken according to PRISMA guidelines. All pathologies and procedures utilizing RAS were included. Studies were limited to RCTs, the English language and publication within the last decade. The main outcomes selected for the review design were safety and efficacy, and study purpose. Secondary outcomes were study characteristics, funding and governance.

RESULTS

Searches identified 7142 titles, from which 183 RCTs were identified for data extraction. The commonest specialty was urology (35·0 per cent). There were just 76 unique study populations, indicating significant overlap of publications; 103 principal studies were assessed further. Only 64·1 per cent of studies reported a primary outcome measure, with 29·1 per cent matching their registration/protocol. Safety was assessed in 68·9 per cent of trials; operative complications were the commonest measure. Forty-eight per cent of trials reported no significant difference in safety between RAS and comparator, and 11 per cent reported RAS to be superior. Efficacy or effectiveness was assessed in 80·6 per cent of trials; 43 per cent of trials showed no difference between RAS and comparator, and 24 per cent reported that RAS was superior. Funding was declared in 47·6 per cent of trials.

CONCLUSION

The evidence base for RAS is of limited quality and variable transparency in reporting. No patterns of harm to patients were identified. RAS has potential to be beneficial, but requires continued high-quality evaluation.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Attracting medical students and doctors into surgical training in the UK and Ireland

AIMS

Core surgical training (CST) programmes in the UK have seen a significant reduction in competition ratios over the past five years. This study aimed to determine motivating factors and perceived barriers to pursuing a career in surgery amongst junior doctors in training and medical students attending an annual conference.

METHODS

A self-reported, electronic questionnaire was distributed to medical students, foundation year doctors, and doctors in postgraduate surgical training programmes (DIPST) who attended the Association of Surgeons in Training (ASiT) Conference in 2016. Respondents ranked factors attracting them to a career in surgery and factors that could improve perceptions of surgical careers. Chi-square test was used to test for differences between groups (a = 0.05, R Studio, V3.3.1).

RESULTS

Of 394 respondents (response rate = 50.9%), 44.9% were medical students or foundation doctors ('Pre-CST') and 55.1% were DIPST ('Peri/post-CST'). Practical application of skills (97.4%), enjoyment of the theatre environment (95.4%) and positive experiences in surgical firms (84.7%) were primary driving factors towards a surgical career. Availability of private practice (32.2%), and sustainability of consultant jobs (49.0%) had less influence. For 'Pre-CST' respondents, role models (82.8% pre-CST v 74.9% peri-post CST, p < 0.05) and defined career progression (67.2% pre-CST v 47.0% peri-post CST, p < 0.001) were particularly important. 91% of all respondents agreed that a better balance of training and service within worked hours would improve perceptions of surgery.

CONCLUSION

Addressing the motivating factors and perceived barriers to surgical careers will help bolster recruitment of the future surgical workforce.

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.

Recommendations for Randomised Trials in Surgical Oncology

Trials of surgical procedures in the treatment of malignant disease face a unique set of challenges. This review aimed to describe recommendations for the design, delivery and reporting of randomised trials in surgical oncology. A literature search was carried out without date limits to identify articles related to trial methodology research in surgery and surgical oncology. A narrative review was framed around two open National Institute of Health Research portfolio trials in colon and rectal cancer: the STAR-TREC trial (ISRCTN14240288) and the ROCCS trial (ISRCTN46330337). Twelve specific challenges were highlighted: standardisation of technique; pilot and feasibility studies; balancing treatments; the recruitment pathway; outcome measures; patient and public representation; trainee-led networks; randomisation; novel techniques and training; learning curves; blinding; follow-up. Evidence-based recommendations were made for the future design and conduct of surgical oncology trials. Better understanding of the challenges facing trials in the surgical treatment of cancer will accelerate high-quality evaluation and rapid adoption of innovation for the benefit of patient care.