A systematic review of automated segmentation of 3D computed-tomography scans for volumetric body composition analysis.

Automated computed tomography (CT) scan segmentation (labelling of pixels according to tissue type) is now possible. This technique is being adapted to achieve three-dimensional (3D) segmentation of CT scans, opposed to single L3-slice alone. This systematic review evaluates feasibility and accuracy of automated segmentation of 3D CT scans for volumetric body composition (BC) analysis, as well as current limitations and pitfalls clinicians and researchers should be aware of. OVID Medline, Embase and grey literature databases up to October 2021 were searched. Original studies investigating automated skeletal muscle, visceral and subcutaneous AT segmentation from CT were included. Seven of the 92 studies met inclusion criteria. Variation existed in expertise and numbers of humans performing ground-truth segmentations used to train algorithms. There was heterogeneity in patient characteristics, pathology and CT phases that segmentation algorithms were developed upon. Reporting of anatomical CT coverage varied, with confusing terminology. Six studies covered volumetric regional slabs rather than the whole body. One study stated the use of whole-body CT, but it was not clear whether this truly meant head-to-fingertip-to-toe. Two studies used conventional computer algorithms. The latter five used deep learning (DL), an artificial intelligence technique where algorithms are similarly organized to brain neuronal pathways. Six of seven reported excellent segmentation performance (Dice similarity coefficients > 0.9 per tissue). Internal testing on unseen scans was performed for only four of seven algorithms, whilst only three were tested externally. Trained DL algorithms achieved full CT segmentation in 12 to 75 s versus 25 min for non-DL techniques. DL enables opportunistic, rapid and automated volumetric BC analysis of CT performed for clinical indications. However, most CT scans do not cover head-to-fingertip-to-toe; further research must validate using common CT regions to estimate true whole-body BC, with direct comparison to single lumbar slice. Due to successes of DL, we expect progressive numbers of algorithms to materialize in addition to the seven discussed in this paper. Researchers and clinicians in the field of BC must therefore be aware of pitfalls. High Dice similarity coefficients do not inform the degree to which BC tissues may be under- or overestimated and nor does it inform on algorithm precision. Consensus is needed to define accuracy and precision standards for ground-truth labelling. Creation of a large international, multicentre common CT dataset with BC ground-truth labels from multiple experts could be a robust solution.

Pathological determinants of outcome following resection of locally advanced or locally recurrent rectal cancer.

INTRODUCTION: Pathological factors that influence and predict survival following pelvic exenteration (PE) for locally advanced (LARC) or locally recurrent rectal cancer (LRRC), especially LRRC, remain poorly understood. A clear resection margin has previously been demonstrated to be of most significance. MATERIALS AND METHODS: A retrospective cohort study was performed for all patients undergoing a curative PE for LARC or LRRC between 2008 and 2021 at a tertiary referral UK specialist colorectal hospital. Cox regression analysis was planned to identify pathological factors associated with overall (OS), disease free (DFS) and local recurrence free survival (LRFS). RESULTS: 388 patients were included in the analysis with 256 resections for LARC and 132 for LRRC. 62.4% of patients were male with a median age of 59 years (IQR 49-67). 247 (64%) partial pelvic exenterations and 141 (36%) total pelvic exenterations performed. Overall R0 rate 86.6%. Poorly differentiated tumours and a positive resection margin independently influenced OS, DFS and LRFS on multivariate analysis in LARC. On multivariate analysis venous invasion negatively influenced DFS and poorly differentiated lesions negatively influenced LRFS in LRRC. CONCLUSIONS: A positive resection margin and poorly differentiated tumours are significant negative prognostic markers for survival and recurrence in LARC. The results of this study support the need to look for alternative prognostic markers beyond that in the existing standard reporting dataset for rectal cancers. With increasing R0 rates, novel prognostic pathological markers are required to help guide treatment and surveillance for patients with LRRC.

A systematic review of the pathological determinants of outcome following resection by pelvic exenteration of locally advanced and locally recurrent rectal cancer.

BACKGROUND: Despite multimodal therapy 5-15% of patients who undergo resection for advanced rectal cancer (LARC) will develop local recurrence. Management of locally recurrent rectal cancer (LRRC) presents a significant therapeutic challenge and even with modern exenterative surgery, 5-year survival rates are poor at 25-50%. High rates of local and systemic recurrence in this cohort are reflective of the likely biological aggressiveness of these tumour types. This review aims to appraise the current literature identifying pathological factors associated with survival and tumour recurrence in patients undergoing exenterative surgery. METHODS: A systematic review was carried out searching MEDLINE, EMBASE and COCHRANE Trials database for all studies assessing pathological factors influencing survival following pelvic exenteration for LARC or LRRC from 2010 to July 2021 following PRISMA guidelines. Risk of bias was assessed using QUIPS tool. RESULTS: Nine cohort studies met inclusion criteria, reporting outcomes for 2864 patients. Meta-analysis was not possible due to significant heterogeneity of reported outcomes. Resection margin status and nodal disease were the most commonly reported factors. A positive resection margin was demonstrated to be a negative prognostic marker in six studies. Involved lymph nodes and lymphovascular invasion also appear to be negative prognostic markers with tumour stage to be of lesser importance. No studies assessed other adverse tumour features that would not otherwise be included in a standard histopathology report. CONCLUSION: Pathological resection margin status is widely demonstrated to influence disease free and overall survival following pelvic exenteration for rectal cancer. With increasing R0 rates, other adverse tumour features must be explored to help elucidate differences in survival and potentially guide tailored oncological treatment.

Tumour grade and stage are associated with specific body composition phenotypes with visceral obesity predisposing the host to a less aggressive tumour in colorectal cancer.

BACKGROUND: Sarcopenia, myosteatosis and visceral obesity (VO) are known to negatively impact on outcomes from colorectal cancer (CRC). Little is known about tumour factors associated with these body composition (BC) phenotypes. We aimed to identify whether histopathological tumour characteristics were associated with various BC phenotypes. METHODS: A prospectively collected database of patients undergoing surgery for primary CRC at a tertiary referral unit in the United Kingdom was analysed. Sarcopenia, myosteatosis and VO were identified on preoperative CT. Binary logistic regression modelling was performed to determine significant associations between tumour stage, grade and BC phenotype. RESULTS: Final analysis included 795 patients; median age 69, 56% male, 65% were sarcopenic, 72% myosteatotic, 52% VO and 20% had sarcopenic obesity (SO). VO patients were significantly less likely to have advanced T Stage (T3-4) OR0.62(95%CI 0.44-0.86, p = 0.005); nodal metastases OR0.60(95%CI 0.44-0.82, p = 0.001); vascular invasion OR0.63(95%CI 0.46-0.88, p = 0.006) and poor tumour differentiation OR0.49(95%CI 0.28-0.86, p = 0.012). Myosteatotic patients were more likely to have metastatic disease OR2.31(95%CI 1.15-4.63, p = 0.018) but less likely to have poorly differentiated tumours OR0.48(95%CI 0.27-0.86, p = 0.013). SO patients were significantly more likely to have poorly differentiated tumours OR2.01(95%CI 1.04-3.87, p = 0.037). CONCLUSION: VO predisposes to earlier stage tumours with a less aggressive tumour phenotype. The SO group have adverse tumour characteristics which may be explained by differences in fat distribution. Myosteatosis relates to increased likelihood of distant metastasis that may be related to a systemic inflammatory response, despite the association with better differentiated tumours.

Altered immunity to microbiota, B cell activation and depleted γδ/resident memory T cells in colorectal cancer.

The role of microbiota:immune system dysregulation in the etiology of colorectal cancer (CRC) is poorly understood. CRC develops in gut epithelium, accompanied by low level inflammatory signaling, intestinal microbial dysbiosis and immune dysfunction. We examined populations of intraepithelial lymphocytes in non-affected colonic mucosa of CRC and healthy donors and circulating immune memory to commensal bacterial species and yeasts. γδ T cells and resident memory T cells, populations with a regulatory CD39-expressing phenotype, were found at lower frequencies in the colonic tissue of CRC donors compared to healthy controls. Patterns of T cell proliferative responses to a panel of commensal bacteria were distinct in CRC, while B cell memory responses to several bacteria/yeast were significantly increased, accompanied by increased proportions of effector memory B cells, transitional B cells and plasmablasts in blood. IgA responses to mucosal microbes were unchanged. Our data describe a novel immune signature with similarities to and differences from that of inflammatory bowel disease. They implicate B cell dysregulation as a potential contributor to parainflammation and identify pathways of weakened barrier function and tumor surveillance in CRC-susceptible individuals.

Altered Mucosal Immune-Microbiota Interactions in Familial Adenomatous Polyposis.

INTRODUCTION: Familial adenomatous polyposis (FAP) is a condition caused by a constitutional pathogenic variant of the adenomatous polyposis coli gene that results in intestinal adenoma formation and colorectal cancer, necessitating pre-emptive colectomy. We sought to examine interaction between the mucosal immune system and commensal bacteria in FAP to test for immune dysfunction that might accelerate tumorigenesis. METHODS: Colonic biopsies were obtained from macroscopically normal mucosal tissue from 14 healthy donors and 13 patients with FAP during endoscopy or from surgical specimens. Intraepithelial and lamina propria lymphocytes were phenotyped. Intraepithelial microbes were labeled with anti-IgA/IgG and analyzed by flow cytometry. RESULTS: Proportions of resident memory CD103-expressing CD8 + and γδ T-cell receptor + intraepithelial lymphocytes were dramatically reduced in both the left and right colon of patients with FAP compared with healthy controls. In lamina propria, T cells expressed less CD103, and CD4 + CD103 + cells expressed less CD73 ectonucleotidase. IgA coating of epithelia-associated bacteria, IgA + peripheral B cells, and CD4 T-cell memory responses to commensal bacteria were increased in FAP. DISCUSSION: Loss of resident memory T cells and γδ T cells in mucosal tissue of patients with FAP accompanies intestinal microbial dysbiosis previously reported in this precancerous state and suggests impaired cellular immunity and tumor surveillance. This may lead to barrier dysfunction, possible loss of regulatory T-cell function, and excess IgA antibody secretion. Our data are the first to implicate mucosal immune dysfunction as a contributing factor in this genetically driven disease and identify potentially critical pathways in the etiology of CRC.

BiCyCLE NMES-neuromuscular electrical stimulation in the perioperative treatment of sarcopenia and myosteatosis in advanced rectal cancer patients: design and methodology of a phase II randomised controlled trial.

BACKGROUND: Colorectal cancer is associated with secondary sarcopenia (muscle loss) and myosteatosis (fatty infiltration of muscle) and patients who exhibit these host characteristics have poorer outcomes following surgery. Furthermore, patients, who undergo curative advanced rectal cancer surgery such as pelvic exenteration, are at risk of skeletal muscle loss due to immobility, malnutrition and a post-surgical catabolic state. Neuromuscular electrical stimulation (NMES) may be a feasible adjunctive treatment to help ameliorate these adverse side-effects. Hence, the purpose of this study is to investigate NMES as an adjunctive pre- and post-operative treatment for rectal cancer patients in the radical pelvic surgery setting and to provide early indicative evidence of efficacy in relation to key health outcomes. METHOD: In a phase II, double-blind, randomised controlled study, 58 patients will be recruited and randomised (1:1) to either a treatment (NMES plus standard care) or placebo (sham-NMES plus standard care) group. The intervention will begin 2 weeks pre-operatively and continue for 8 weeks after exenterative surgery. The primary outcome will be change in mean skeletal muscle attenuation, a surrogate marker of myosteatosis. Sarcopenia, quality of life, inflammatory status and cancer specific outcomes will also be assessed. DISCUSSION: This phase II randomised controlled trial will provide important preliminary evidence of the potential for this adjunctive treatment. It will provide guidance on subsequent development of phase 3 studies on the clinical benefit of NMES for rectal cancer patients in the radical pelvic surgery setting. TRIAL REGISTRATION: Protocol version 6.0; 05/06/20. ClinicalTrials.gov NCT04065984 . Registered on 22 August 2019; recruiting.

Evolution of the management of retrorectal masses: A retrospective cohort study.

AIM: Retrorectal masses are abnormalities located anatomically in the retrorectal space. A significant proportion are asymptomatic with no malignant potential while others cause symptoms due to mechanical pressure or malignant infiltration. We reviewed and categorised the retrorectal masses encountered over a 30-year time period in a specialist colorectal hospital and describe our management algorithm for consideration by other multidisciplinary teams (MDT). METHODS: This was a retrospective analysis of consecutive patients referred between 1984-2019. A detailed review of clinical presentation, imaging features, postoperative histology and impact on morbidity and anorectal function is reported. RESULTS: A total of 143 patients with median age of 46 years and female preponderance (74%) were reviewed. The commonest presenting symptom was pain (46%) and all malignant cases had symptoms (n = 17). Over the last decade, more asymptomatic patients have presented with a retrorectal mass (33%, p = 0.04) and more patients are opting for surveillance rather than resection (33%, p = 0.013). Increasing age and lesion size were associated with malignancy (p < 0.05). Radiological features associated with malignancy included: solid/heterogeneous component, lobulated borders or locally invasive. Following surgery, complications included chronic pain (40%), poor wound healing (23%) and bowel dysfunction (10%). CONCLUSIONS: The management of retrorectal masses remains complex. There are features, both clinical and radiological, that can help determine the best management strategy. Management should be in a high-volume tertiary centre and preferably through a complex rectal cancer MDT. Long-term sequelae such as chronic pain must be highlighted to patients. We advocate the establishment of an international registry to further record and characterise these rare, potentially troublesome lesions.

Crisis management for surgical teams and their leaders, lessons from the COVID-19 pandemic; A structured approach to developing resilience or natural organisational responses.

BACKGROUND: Multiple industries and organisations are afflicted by and respond to institutional crises daily. As surgeons, we respond to crisis frequently and individually such as with critically unwell patients or in mass casualty scenarios; but rarely, do we encounter institutional or multi-institutional crisis with multiple actors as we have seen with the COVID-19 pan-demic. Businesses, private industry and the financial sector have been in a more precar-ious position regarding crisis and consequently have developed rapid response strate-gies employing foresight to reduce risk to assets and financial liquidity. Moreover, large nationalised governmental organisations such as the military have strategies in place ow-ing to a rapidly evolving geopolitical climate with the expectation of immediate new chal-lenges either in the negotiating room or indeed the field of conflict. Despite both nation-alised and privatised healthcare systems existing, both appeared ill-prepared for the COVID-19 global crisis. METHODS: A narrative review of the literature was undertaken exploring the approach to crisis man-agement and models used in organisations exposed to institutional crises outside the field of medicine. RESULTS: There are many parallels between the organisational management of private business institutions, large military organisations and surgical organisational management in healthcare. Models from management consultancies and the armed forces were ex-plored discussed and adapted for the surgical leader providing a framework through which the surgical leader can bring about an successful response to an institutional crisis and ensure future resilience. CONCLUSION: We believe that healthcare, and surgeons (as leaders) in particular, can learn from these other organisations and industries to engage appropriate generic operational plans and contingencies in preparation for whatever further crises may arise in the future, both near and distant. As such, following a review of the literature, we have explored a number of models we believe are adaptable for the surgical community to ensure we remain a dy-namically responsive and ever prepared profession.

Cancer cachexia and myopenia - Update on management strategies and the direction of future research for optimizing body composition in cancer - A narrative review.

PURPOSE: Body composition degenerates with cancer. Optimizing body composition is rarely, if ever, undertaken. This narrative review highlights and evaluates emerging treatments that have the potential to improve outcomes for our cancer patients. OBSERVATIONS: Body composition in cancer patients has been shown to be modifiable; enhanced body composition is associated with improved short term, long-term outcomes and survival in addition to improvements in function and quality of life. CONCLUSIONS AND RELEVANCE: A multimodal approach to body composition optimization formulated by a multidisciplinary team in a patient-centric manner can improve outcome. As part of a multifaceted approach to patient treatment, body composition modification should be considered to expand our armoury in fighting the systemic burden of cancer.

Perioperative risk prediction in the era of enhanced recovery: a comparison of POSSUM, ACPGBI, and E-PASS scoring systems in major surgical procedures of the colorectal surgeon.

PURPOSE: This study aims to determine whether traditional risk models can accurately predict morbidity and mortality in patients undergoing major surgery by colorectal surgeons within an enhanced recovery program. METHODS: One thousand three hundred eighty patients undergoing surgery performed by colorectal surgeons in a single UK hospital (2008-2013) were included. Six risk models were evaluated: (1) Physiology and Operative Severity Score for the enumeration of Mortality and Morbidity (POSSUM), (2) Portsmouth POSSUM (P-POSSUM), (3) ColoRectal (CR-POSSUM), (4) Elderly POSSUM (E-POSSUM), (5) the Association of Great Britain and Ireland (ACPGBI) score, and (6) modified Estimation of Physiologic Ability and Surgical Stress Score (E-PASS). Model accuracy was assessed by observed to expected (O:E) ratios and area under Receiver Operating Characteristic curve (AUC). RESULTS: Eleven patients (0.8%) died and 143 patients (10.4%) had a major complication within 30 days of surgery. All models overpredicted mortality and had poor discrimination: POSSUM 8.5% (O:E 0.09, AUC 0.56), P-POSSUM 2.2% (O:E 0.37, AUC 0.56), CR-POSSUM 7.1% (O:E 0.11, AUC 0.61), and E-PASS 3.0% (O:E 0.27, AUC 0.46). ACPGBI overestimated mortality in patients undergoing surgery for cancer 4.4% (O:E = 0.28, AUC = 0.41). Predicted morbidity was also overestimated by POSSUM 32.7% (O:E = 0.32, AUC = 0.51). E-POSSUM overestimated mortality (3.25%, O:E 0.57 AUC = 0.54) and morbidity (37.4%, O:E 0.30 AUC = 0.53) in patients aged ≥ 70 years and over. CONCLUSION: All models overestimated mortality and morbidity. New models are required to accurately predict the risk of adverse outcome in patients undergoing major abdominal surgery taking into account the reduced physiological and operative insult of laparoscopic surgery and enhanced recovery care.