Reporting of health-related quality of life in emergency laparotomy trials: a systematic review and narrative synthesis.

PURPOSE: Emergency laparotomy is associated with high morbidity for the surgical patient. Understanding patients' health-related quality of life after their surgery is important to enhance the informed consent process, and to enable the evaluation and improvement of surgical care. This review aims to summarise the use of health-related quality of life tools in clinical trials involving patients undergoing emergency laparotomy. METHODS: A systematic review was undertaken of the scientific literature published in the MEDLINE® and PubMed databases between January 2011 and July 2021. A narrative synthesis approach was chosen to synthesise the diverse range of studies in a structured manner. All included papers were evaluated using the Cochrane Collaboration's tool for assessing risk of bias. RESULTS: Eleven studies were selected for inclusion. Most of the studies had a low risk of bias. Two of the studies used health-related quality of life as the primary outcome measure. A variety of health-related quality of life measurement tools were used; the EQ-5D tool was the most popular questionnaire. Protocol adherence was dependent on the length of time which had elapsed after emergency surgery. CONCLUSION: There are many perceived challenges to collecting health-related quality of life data in the emergency surgery setting. Many of these can be offset with progressive trial designs. There is a need for further research in the systematic development of patient-reported outcomes for use in emergency surgery.

Patient education about recovery after colorectal surgery: systematic scoping review.

AIM: Enhanced recovery after surgery (ERAS) protocols aim to optimize recovery through a series of evidence-based recommendations. A key component of ERAS is the provision of patient education. Whilst the recommendation for this is strong, the evidence to inform its format, timing and delivery is unclear. The aim of this review was to describe previous educational interventions used to improve recovery after colorectal surgery and to explore opportunities for future research. METHODS: A systematic scoping review was performed. MEDLINE and Embase databases were searched between 1 January 1990 and 12 February 2020. Studies which described or assessed the effectiveness of a patient education or information resource to improve recovery after colorectal surgery were eligible. Outcomes of interest included the format, timing and delivery of interventions, as well as key features of intervention and study design. A narrative synthesis of data was produced through a process of charting and summarizing key results. RESULTS: A total of 1298 papers were inspected, and 11 were eligible for inclusion. Five papers were reports of randomized controlled trials, and others reported a mix of non-randomized and qualitative studies. The design of educational interventions included audio-visual resources (n = 3), smartphone device applications (n = 3) and approaches to facilitate person-to-person counselling (n = 5). Most of the counselling interventions reported positive outcomes (mainly in length of hospital stay), whereas the other types reported mixed results. Patients and the public were seldom involved as collaborators in the design of interventions. CONCLUSIONS: Patient education is generally advantageous, but there is insufficient evidence to optimize its design and delivery in the setting of colorectal surgery.

Establishing core outcome sets for gastrointestinal recovery in studies of postoperative ileus and small bowel obstruction: protocol for a nested methodological study.

INTRODUCTION: Gastrointestinal recovery describes the restoration of normal bowel function in patients with bowel disease. This may be prolonged in two common clinical settings: postoperative ileus and small bowel obstruction. Improving gastrointestinal recovery is a research priority but researchers are limited by variation in outcome reporting across clinical studies. This protocol describes the development of core outcome sets for gastrointestinal recovery in the contexts of postoperative ileus and small bowel obstruction. METHOD: An international Steering Group consisting of patient and clinician representatives has been established. As overlap between clinical contexts is anticipated, both outcome sets will be co-developed and may be combined to form a common output with disease-specific domains. The development process will comprise three phases, including definition of outcomes relevant to postoperative ileus and small bowel obstruction from systematic literature reviews and nominal-group stakeholder discussions; online-facilitated Delphi surveys via international networks; and a consensus meeting to ratify the final output. A nested study will explore if the development of overlapping outcome sets can be rationalized. DISSEMINATION AND IMPLEMENTATION: The final output will be registered with the Core Outcome Measures in Effectiveness Trials initiative. A multi-faceted, quality improvement campaign for the reporting of gastrointestinal recovery in clinical studies will be launched, targeting international professional and patient groups, charitable organizations and editorial committees. Success will be explored via an updated systematic review of outcomes 5 years after registration of the core outcome set.

Research waste in surgical randomized controlled trials.

BACKGROUND: Research waste is a major challenge for evidence-based medicine. It implicates misused resources and increased risks for research participants. The aim of this study was to quantify constituent components of waste in surgical RCTs and explore targets for improvement. METHODS: ClinicalTrials.gov was searched for RCTs registered between January 2011 and December 2012 using the keyword 'surgery'. The primary outcome was research waste, defined as non-publication, inadequate reporting or presence of an avoidable design limitation. Serial systematic searches of PubMed and Scopus databases were performed to determine publication status. Adequacy of reporting was assessed using the CONSORT checklist. Avoidable design limitations were evaluated according to the presence of bias and/or the absence of a cited systematic review of the literature. RESULTS: Of 5617 registered RCTs, 304 met all eligibility criteria. Overall, 259 of 304 (85·2 per cent) demonstrated at least one feature of waste. Of these, 221 (72·7 per cent) were published in a peer-reviewed journal and 219 were accessible for full-text review. Only 73 of 131 (55·7 per cent) RCTs with a pharmacological intervention and 24 of 88 (27 per cent) with a non-pharmacological intervention were reported adequately, and 159 of 219 (72·6 per cent) demonstrated an avoidable design limitation. Multicentre (odds ratio 0·31, 95 per cent c.i. 0·11 to 0·88) and externally funded (OR 0·35, 0·15 to 0·82) RCTs were less associated with research waste. CONCLUSION: This study identified a considerable burden of research waste in surgical RCTs. Future initiatives should target improvements in single-centre, poorly supported RCTs.

ANTECEDENTES: El despilfarro en investigación es uno de los mayores retos para la medicina basada en la evidencia. Conlleva mala utilización de los recursos y aumento de los riesgos para los participantes en las investigaciones. El objetivo de este trabajo fue cuantificar los componentes que conforman este despilfarro en los ensayos aleatorizados y controlados (randomised controlled trials, RCTs) del ámbito quirúrgico y explorar los aspectos clave de mejora. MÉTODOS: Se realizó una búsqueda de los RCTs registrados en la base de datos ClinicalTrials.gov entre enero de 2011 y diciembre de 2012, utilizando la palabra clave cirugía. La variable primaria fue el despilfarro en investigación, definido como la no publicación, el informe inadecuado o la presencia de debilidades del diseño evitables. Para determinar el estado de las publicaciones, se realizaron búsquedas sistemáticas en las bases de datos PubMed y Scopus. La adecuación del informe se evaluó usando la lista de verificación CONSORT. Las debilidades del diseño evitables se evaluaron de acuerdo con la presencia de sesgo y/o la ausencia de citación en revisiones sistemáticas publicadas en la literatura. RESULTADOS: De los 5.617 RCTs registrados, 304 cumplieron con los criterios de elegibilidad. De ellos, 259/304 (85%) cumplieron al menos una de las características de despilfarro. De estos, 221 (73%) se publicaron en una revista con peer review y 219 eran accesibles a texto completo. Únicamente 73/131 (56%) RCTs con una intervención farmacológica y 24/88 (27%) con una intervención no farmacológica presentaban un informe adecuado, y 159/219 (73%) se demostró una debilidad del diseño evitable. Los RCTs multicéntricos (OR: 0,31; i.c. del 95%: 0,11 a 0,88) y con financiación externa (OR: 0,35; i.c. del 95%: 0,15 a 0,82) se asociaron con menos despilfarro de investigación. CONCLUSIÓN: Este estudio constató una carga considerable de despilfarro en investigación en los RCTs quirúrgicos. Se deberían promover iniciativas de mejora, especialmente dirigidas a los RCTs realizados en un solo centro y con menos financiación.

Avoiding, diagnosing and treating well leg compartment syndrome after pelvic surgery.

BACKGROUND: Patients undergoing prolonged pelvic surgery may develop compartment syndrome of one or both lower limbs in the absence of direct trauma or pre-existing vascular disease (well leg compartment syndrome). This condition may have devastating consequences for postoperative recovery, including loss of life or limb, and irreversible disability. METHODS: These guidelines represent the collaboration of a multidisciplinary group of colorectal, vascular and orthopaedic surgeons, acting on behalf of their specialty associations in the UK and Ireland. A systematic analysis of the available peer-reviewed literature was undertaken to provide an evidence base from which these guidelines were developed. RESULTS: These guidelines encompass the risk factors (both patient- and procedure-related), diagnosis and management of the condition. Key recommendations for the adoption of perioperative strategies to facilitate prevention and effective treatment of well leg compartment syndrome are presented. CONCLUSION: All surgeons who carry out abdominopelvic surgical procedures should be aware of well leg compartment syndrome, and instigate policies within their own institution to reduce the risk of this potentially life-changing complication.

Disseminating technology in global surgery.

BACKGROUND: Effective dissemination of technology in global surgery is vital to realize universal health coverage by 2030. Challenges include a lack of human resource, infrastructure and finance. Understanding these challenges, and exploring opportunities and solutions to overcome them, are essential to improve global surgical care. METHODS: This review focuses on technologies and medical devices aimed at improving surgical care and training in low- and middle-income countries. The key considerations in the development of new technologies are described, along with strategies for evaluation and wider dissemination. Notable examples of where the dissemination of a new surgical technology has achieved impact are included. RESULTS: Employing the principles of frugal and responsible innovation, and aligning evaluation and development to high scientific standards help overcome some of the challenges in disseminating technology in global surgery. Exemplars of effective dissemination include low-cost laparoscopes, gasless laparoscopic techniques and innovative training programmes for laparoscopic surgery; low-cost and versatile external fixation devices for fractures; the LifeBox pulse oximeter project; and the use of immersive technologies in simulation, training and surgical care delivery. CONCLUSION: Core strategies to facilitate technology dissemination in global surgery include leveraging international funding, interdisciplinary collaboration involving all key stakeholders, and frugal scientific design, development and evaluation.

Postoperative ileus following major colorectal surgery.

BACKGROUND: Postoperative ileus (POI) is characterized by delayed gastrointestinal recovery following surgery. Current knowledge of pathophysiology, clinical interventions and methodological challenges was reviewed to inform modern practice and future research. METHODS: A systematic search of MEDLINE and Embase databases was performed using search terms related to ileus and colorectal surgery. All RCTs involving an intervention to prevent or reduce POI published between 1990 and 2016 were identified. Grey literature, non-full-text manuscripts, and reanalyses of previous RCTs were excluded. Eligible articles were assessed using the Cochrane tool for assessing risk of bias. RESULTS: Of 5614 studies screened, 86 eligible articles describing 88 RCTs were identified. Current knowledge of pathophysiology acknowledges neurogenic, inflammatory and pharmacological mechanisms, but much of the evidence arises from animal studies. The most common interventions tested were chewing gum (11 trials) and early enteral feeding (11), which are safe but of unclear benefit for actively reducing POI. Others, including thoracic epidural analgesia (8), systemic lidocaine (8) and peripheral µ antagonists (5), show benefit but require further investigation for safety and cost-effectiveness. CONCLUSION: POI is a common condition with no established definition, aetiology or treatment. According to current literature, minimally invasive surgery, protocol-driven recovery (including early feeding and opioid avoidance strategies) and measures to avoid major inflammatory events (such as anastomotic leak) offer the best chances of reducing POI.

The timing of liver resection in patients with colorectal cancer and synchronous liver metastases: a population-based study of current practice and survival.

AIM: There is uncertainty regarding the optimal sequence of surgery for patients with colorectal cancer (CRC) and synchronous liver metastases. This study was designed to describe temporal trends and inter-hospital variation in surgical strategy, and to compare long-term survival in a propensity score-matched analysis. METHOD: The National Bowel Cancer Audit dataset was used to identify patients diagnosed with primary CRC between 1 January 2010 and 31 December 2015 who underwent CRC resection in the English National Health Service. Hospital Episode Statistics data were used to identify those with synchronous liver-limited metastases who underwent liver resection. Survival outcomes of propensity score-matched groups were compared. RESULTS: Of 1830 patients, 270 (14.8%) underwent a liver-first approach, 259 (14.2%) a simultaneous approach and 1301 (71.1%) a bowel-first approach. The proportion of patients undergoing either a liver-first or simultaneous approach increased over the study period from 26.8% in 2010 to 35.6% in 2015 (P < 0.001). There was wide variation in surgical approach according to hospital trust of diagnosis. There was no evidence of a difference in 4-year survival between the propensity score-matched cohorts according to surgical strategy: bowel first vs simultaneous [hazard ratio (HR) 0.92 (95% CI: 0.80-1.06)] or bowel first vs liver first [HR 0.99 (95% CI: 0.82-1.19)]. CONCLUSION: There is evidence of wide variation in surgical strategy in dealing with CRC and synchronous liver metastases. In selected patients, the simultaneous and liver-first strategies have comparable long-term survival to the bowel-first approach.

Impact of hepatobiliary service centralization on treatment and outcomes in patients with colorectal cancer and liver metastases.

BACKGROUND: Centralization of specialist surgical services can improve patient outcomes. The aim of this cohort study was to compare liver resection rates and survival in patients with primary colorectal cancer and synchronous metastases limited to the liver diagnosed at hepatobiliary surgical units (hubs) with those diagnosed at hospital Trusts without hepatobiliary services (spokes). METHODS: The study included patients from the National Bowel Cancer Audit diagnosed with primary colorectal cancer between 1 April 2010 and 31 March 2014 who underwent colorectal cancer resection in the English National Health Service. Patients were linked to Hospital Episode Statistics data to identify those with liver metastases and those who underwent liver resection. Multivariable random-effects logistic regression was used to estimate the odds ratio of liver resection by presence of specialist hepatobiliary services on site. Survival curves were estimated using the Kaplan-Meier method. RESULTS: Of 4547 patients, 1956 (43·0 per cent) underwent liver resection. The 1081 patients diagnosed at hubs were more likely to undergo liver resection (adjusted odds ratio 1·52, 95 per cent c.i. 1·20 to 1·91). Patients diagnosed at hubs had better median survival (30·6 months compared with 25·3 months for spokes; adjusted hazard ratio 0·83, 0·75 to 0·91). There was no difference in survival between hubs and spokes when the analysis was restricted to patients who had liver resection (P = 0·620) or those who did not undergo liver resection (P = 0·749). CONCLUSION: Patients with colorectal cancer and synchronous metastases limited to the liver who are diagnosed at hospital Trusts with a hepatobiliary team on site are more likely to undergo liver resection and have better survival.

A collaborative review of the current concepts and challenges of anastomotic leaks in colorectal surgery.

The reduction of the incidence, detection and treatment of anastomotic leakage (AL) continues to challenge the colorectal surgical community. AL is not consistently defined and reported in clinical studies, its occurrence is variably reported and its impact on longterm morbidity and health-care resources has received relatively little attention. Controversy continues regarding the best strategies to reduce the risk. Diagnostic tests lack sensitivity and specificity, resulting in delayed diagnosis and increased morbidity. Intra-operative fluorescence angiography has recently been introduced as a means of real-time assessment of anastomotic perfusion and preliminary evidence suggests that it may reduce the rate of AL. In addition, concepts are emerging about the role of the rectal mucosal microbiome in AL and the possible role of new prophylactic therapies. In January 2016 a meeting of expert colorectal surgeons and pathologists was held in London, UK, to identify the ongoing controversies surrounding AL in colorectal surgery. The outcome of the meeting is presented in the form of research challenges that need to be addressed.

Use of a patient completed iPad questionnaire to improve pre-operative assessment.

Developments in healthcare technology could improve patient care and reduce healthcare costs. There is a need to facilitate communication and increase efficiency in surgical pre-assessment clinics. This study aimed to develop an iPad application to deliver an electronic patient questionnaire, and to evaluate its use in the pre-assessment environment. Software was developed, MyOp, for a standard iPad that mirrored the paper-based pre-assessment system, with features designed for ease of patient use and remote data transfer. A case-control study was conducted, comparing use of MyOp with paper-based practice, to evaluate feasibility and patient preference. Patients were offered the use of MyOp or paper-based system. Outcomes measured included time to complete iPad questionnaire, consultation duration, and a patient preference questionnaire. MyOp cost £3500 to develop. 104 individuals participated in the study, 53 MyOp and 51 controls. MyOp reduced the median consultation duration by 5.00 min. A reduction was seen in all subgroups except those aged over 70 or urology patients. Patients preferred to complete the form independently, using a touchpad or computer but expressed concerns about data security. Use of an electronic patient questionnaire reduces consultation time delivering greater efficiency of pre-assessment nurse time. Preconceived ideas about the use of technology in older age groups are likely inaccurate and less of a barrier than previously thought. Electronic pre-assessments could be used routinely to reduce demands on healthcare facilities, improve patient care, and triage patients prior to clinic attendance.

Systemic neutrophil-to-lymphocyte ratio in colorectal cancer: the relationship to patient survival, tumour biology and local lymphocytic response to tumour.

BACKGROUND: Colorectal cancer (CRC) is a major cause of mortality and morbidity. The impact of inflammatory biomarkers (C-reactive protein etc.) on CRC is increasingly studied including systemic neutrophil-to-lymphocyte ratio (NLR) as they seem to predict outcome. METHODS: All patients who underwent curative resection for CRC from 2000 to 2004 at Leeds Teaching Hospitals NHS Trust had pre-operative NLR calculated. Demographic, histopathological and survival data were collected. Tissue microarrays were created and stained to determine the mismatch repair (MMR) protein status of each tumour. Local lymphocytic response to the tumour was assessed and graded. RESULTS: About 358 patients were eligible. Of these 88 had an NLR ⩾5, which predicted lower overall survival and greater disease recurrence. A high NLR is associated with higher pT- and pN-stage and a greater incidence of extramural venous invasion. MMR protein status was not associated with NLR. A pronounced lymphocytic reaction at the invasive margin (IM) indicated a better prognosis and was associated with a lower NLR. CONCLUSION: Neutrophil-to-lymphocyte ratio predicts disease-free and overall survival and is associated with a more aggressive tumour phenotype. The lymphocytic response to tumour at the IM is associated with NLR however dMMR is not. Neutrophil-to-lymphocyte ratio is a cheap, easy-to-access test that predicts outcome in CRC.

Synthesis and summary of patient-reported outcome measures to inform the development of a core outcome set in colorectal cancer surgery.

AIM: Patient-reported outcome (PRO) measures (PROMs) are standard measures in the assessment of colorectal cancer (CRC) treatment, but the range and complexity of available PROMs may be hindering the synthesis of evidence. This systematic review aimed to: (i) summarize PROMs in studies of CRC surgery and (ii) categorize PRO content to inform the future development of an agreed minimum 'core' outcome set to be measured in all trials. METHOD: All PROMs were identified from a systematic review of prospective CRC surgical studies. The type and frequency of PROMs in each study were summarized, and the number of items documented. All items were extracted and independently categorized by content by two researchers into 'health domains', and discrepancies were discussed with a patient and expert. Domain popularity and the distribution of items were summarized. RESULTS: Fifty-eight different PROMs were identified from the 104 included studies. There were 23 generic, four cancer-specific, 11 disease-specific and 16 symptom-specific questionnaires, and three ad hoc measures. The most frequently used PROM was the EORTC QLQ-C30 (50 studies), and most PROMs (n = 40, 69%) were used in only one study. Detailed examination of the 50 available measures identified 917 items, which were categorized into 51 domains. The domains comprising the most items were 'anxiety' (n = 85, 9.2%), 'fatigue' (n = 67, 7.3%) and 'physical function' (n = 63, 6.9%). No domains were included in all PROMs. CONCLUSION: There is major heterogeneity of PRO measurement and a wide variation in content assessed in the PROMs available for CRC. A core outcome set will improve PRO outcome measurement and reporting in CRC trials.

Systematic review of methods to predict and detect anastomotic leakage in colorectal surgery.

AIM: Anastomotic leakage is a serious complication of gastrointestinal surgery resulting in increased morbidity and mortality, poor function and predisposing to cancer recurrence. Earlier diagnosis and intervention can minimize systemic complications but is hindered by current diagnostic methods that are non-specific and often uninformative. The purpose of this paper is to review current developments in the field and to identify strategies for early detection and treatment of anastomotic leakage. METHOD: A systematic literature search was performed using the MEDLINE, Embase, PubMed and Cochrane Library databases. Search terms included 'anastomosis' and 'leak' and 'diagnosis' or 'detection' and 'gastrointestinal' or 'colorectal'. Papers concentrating on the diagnosis of gastrointestinal anastomotic leak were identified and further searches were performed by cross-referencing. RESULTS: Computerized tomography CT scanning and water-soluble contrast studies are the current preferred techniques for diagnosing anastomotic leakage but suffer from variable sensitivity and specificity, have logistical constraints and may delay timely intervention. Intra-operative endoscopy and imaging may offer certain advantages, but the ability to predict anastomotic leakage is unproven. Newer techniques involve measurement of biomarkers for anastomotic leakage and have the potential advantage of providing cheap real-time monitoring for postoperative complications. CONCLUSION: Current diagnostic tests often fail to diagnose anastomotic leak at an early stage that enables timely intervention and minimizes serious morbidity and mortality. Emerging technologies, based on detection of local biomarkers, have achieved proof of concept status but require further evaluation to determine whether they translate into improved patient outcomes. Further research is needed to address this important, yet relatively unrecognized, area of unmet clinical need.

Carcinoembryonic antigen is the preferred biomarker for in vivo colorectal cancer targeting.

BACKGROUND: Colorectal cancer-specific biomarkers have been used as molecular targets for fluorescent intra-operative imaging, targeted PET/MRI, and selective cytotoxic drug delivery yet the selection of biomarkers used is rarely evidence-based. We evaluated sensitivities and specificites of four of the most commonly used markers: carcinoembryonic antigen (CEA), tumour-associated glycoprotein-72 (TAG-72), folate receptor-α (FRα) and Epithelial growth factor receptor (EGFR). METHODS: Marker expression was evaluated semi-quantitatively in matched mucosal and colorectal cancer tissues from 280 patients using immunohistochemistry (scores of 0-15). Matched positive and negative lymph nodes from 18 patients were also examined. RESULTS: Markers were more highly expressed in tumour tissue than in matched normal tissue in 98.8%, 79.0%, 37.1% and 32.8% of cases for CEA, TAG-72, FRα and EGFR, respectively. Carcinoembryonic antigen showed the greatest differential expression, with tumours scoring a mean of 10.8 points higher than normal tissues (95% CI 10.31-11.21, P<0.001). Similarly, CEA showed the greatest differential expression between positive and negative lymph nodes. Receiver operating characteristic analyses showed CEA to have the best sensitivity (93.7%) and specificity (96.1%) for colorectal cancer detection. CONCLUSION: Carcinoembryonic antigen has the greatest potential to allow highly specific tumour imaging and drug delivery; future translational research should aim to exploit this.

Long-term follow-up of the Medical Research Council CLASICC trial of conventional versus laparoscopically assisted resection in colorectal cancer.

BACKGROUND: Laparoscopic resection is used widely in the management of colorectal cancer; however, the data on long-term outcomes, particularly those related to rectal cancer, are limited. The results of long-term follow-up of the UK Medical Research Council trial of laparoscopically assisted versus open surgery for colorectal cancer are presented. METHODS: A total of 794 patients from 27 UK centres were randomized to laparoscopic or open surgery in a 2:1 ratio between 1996 and 2002. Long-term follow-up data were analysed to determine differences in survival outcomes and recurrences for intention-to-treat and actual treatment groups. RESULTS: Median follow-up of all patients was 62·9 (interquartile range 22·9 - 92·8) months. There were no statistically significant differences between open and laparoscopic groups in overall survival (78·3 (95 per cent confidence interval (c.i.) 65·8 to 106·6) versus 82·7 (69·1 to 94·8) months respectively; P = 0·780) and disease-free survival (DFS) (89·5 (67·1 to 121·7) versus 77·0 (63·3 to 94·0) months; P = 0·589). In colonic cancer intraoperative conversions to open surgery were associated with worse overall survival (hazard ratio (HR) 2·28, 95 per cent c.i. 1·47 to 3·53; P < 0·001) and DFS (HR 2·20, 1·31 to 3·67; P = 0·007). In terms of recurrence, no significant differences were observed by randomized procedure. However, at 10 years, right colonic cancers showed an increased propensity for local recurrence compared with left colonic cancers: 14·7 versus 5·2 per cent (difference 9·5 (95 per cent c.i. 2·3 to 16·6) per cent; P = 0·019). CONCLUSION: Long-term results continue to support the use of laparoscopic surgery for both colonic and rectal cancer.

A systematic review of outcome reporting in colorectal cancer surgery.

AIM: Evaluation of surgery for colorectal cancer (CRC) is necessary to inform clinical decision-making and healthcare policy. The standards of outcome reporting after CRC surgery have not previously been considered. METHOD: Systematic literature searches identified randomized and nonrandomized prospective studies reporting clinical outcomes of CRC surgery. Outcomes were listed verbatim, categorized into broad groups (outcome domains) and examined for a definition (an appropriate textual explanation or a supporting citation). Outcome reporting was considered inconsistent if results of the outcome specified in the methods were not reported. Outcome reporting was compared between randomized and nonrandomized studies. RESULTS: Of 5644 abstracts, 194 articles (34 randomized and 160 nonrandomized studies) were included reporting 766 different clinical outcomes, categorized into seven domains. A mean of 14 ± 8 individual outcomes were reported per study. 'Anastomotic leak', 'overall survival' and 'wound infection' were the three most frequently reported outcomes in 72, 60 and 44 (37.1%, 30.9% and 22.7%) studies, respectively, and no single outcome was reported in every publication. Outcome definitions were significantly more often provided in randomized studies than in nonrandomized studies (19.0% vs 14.9%, P = 0.015). One-hundred and twenty-seven (65.5%) papers reported results of all outcomes specified in the methods (randomized studies, n = 21, 61.5%; nonrandomized studies, n = 106, 66.2%; P = 0.617). CONCLUSION: Outcome reporting in CRC surgery lacks consistency and method. Improved standards of outcome measurement are recommended to permit data synthesis and transparent cross-study comparisons.