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.

Patient and multidisciplinary team perspectives on watch and wait in rectal cancer.

This article adopts a multidisciplinary approach, including surgery, oncology, radiology and patient perspectives, to discuss the key points of debate surrounding a watch and wait approach. In an era of shared decision-making, discussion of watch and wait as an option in the context of complete clinical response is appropriate, although it is not the gold standard treatment. Key challenges are the difficulty in assessing for a complete clinical response, prediction of recurrence and access to timely diagnostics for surveillance. Salvage surgery has good results if regrowth is detected early but does have imperfect outcomes, with only a 90% salvage rate. Good communication with patients about the risks and alternatives is essential. Patients undergoing watch and wait should ideally be enrolled in prospective registries or clinical trials.

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.

Protective ileostomy creation after anterior resection of the rectum: Shared decision-making or still subjective?

AIM: The choice of whether to perform protective ileostomy (PI) after anterior resection (AR) is mainly guided by risk factors (RFs) responsible for the development of anastomotic leakage (AL). However, clear guidelines about PI creation are still lacking in the literature and this is often decided according to the surgeon's preferences, experiences or feelings. This qualitative study aims to investigate, by an open-ended question survey, the individual surgeon's decision-making process regarding PI creation after elective AR. METHOD: Fifty four colorectal surgeons took part in an electronic survey to answer the questions and describe what usually led their decision to perform PI. A content analysis was used to code the answers. To classify answers, five dichotomous categories (In favour/Against PI, Listed/Unlisted RFs, Typical/Atypical, Emotions/Non-emotions, Personal experience/No personal experience) have been developed. RESULTS: Overall, 76% of surgeons were in favour of PI creation and 88% considered listed RFs in the question of whether to perform PI. Atypical answers were reported in 10% of cases. Emotions and personal experience influenced surgeons' decision-making process in 22% and 49% of cases, respectively. The most frequently considered RFs were the distance of the anastomosis from the anal verge (96%), neoadjuvant chemoradiotherapy (88%), a positive intraoperative leak test (65%), blood loss (37%) and immunosuppression therapy (35%). CONCLUSION: The indications to perform PI following rectal cancer surgery lack standardization and evidence-based guidelines are required to inform practice. Until then, expert opinion can be helpful to assist the decision-making process in patients who have undergone AR for adenocarcinoma.

Pancreaticoduodenectomy with right hemicolectomy for advanced malignancy: a single UK hepatopancreaticobiliary centre experience.

AIM: Locally advanced intestinal neoplasms including colon cancer may require radical en bloc pancreaticoduodenectomy and right hemicolectomy (PD-RC) to achieve curative, margin-negative resection, but the safety and benefit of this uncommon procedure has not been established. The Association of Coloproctology of Great Britain and Ireland IMPACT initiative has also highlighted a lack of awareness about current services available within the UK for patients with advanced colorectal cancer and concerns about low-volume centres managing complex cases. Thus, we aimed to review the feasibility, safety and long-term outcomes of this procedure at a single high-volume hepatopancreaticobiliary surgery unit in the UK. METHOD: A retrospective cohort study was performed using a database of all consecutive patients with intestinal cancer who had been referred to our regional advanced multidisciplinary team and undergone PD-RC in a 7-year period (2013-2020). Clinico-pathological and outcome data were reviewed. RESULTS: Ten patients (mean age 54 ± 13, 8/10 men) were identified. Final histology revealed the primary tumour sites were colon (n = 7) and duodenum (n = 3). R0 resection was achieved in all cases. The major complication rate (Clavien-Dindo ≥ 3) was 10% (1/10) with no deaths within 90 days of surgery. The Kaplan-Meier estimated 5-year overall survival was 83.3% (95% CI 58.3%-100%). Univariate survival analysis identified perineural invasion and extra-colonic origin as predictors of poor survival (log-rank P < 0.05). CONCLUSION: En bloc PD-RC for locally advanced intestinal cancer can be performed safely with a high proportion of margin-negative resections and resultant long-term survival in carefully selected patients.

Benchmarks in colorectal surgery: multinational study to define quality thresholds in high and low anterior resection.

BACKGROUND: Benchmark comparisons in surgery allow identification of gaps in the quality of care provided. The aim of this study was to determine quality thresholds for high (HAR) and low (LAR) anterior resections in colorectal cancer surgery by applying the concept of benchmarking. METHODS: This 5-year multinational retrospective study included patients who underwent anterior resection for cancer in 19 high-volume centres on five continents. Benchmarks were defined for 11 relevant postoperative variables at discharge, 3 months, and 6 months (for LAR). Benchmarks were calculated for two separate cohorts: patients without (ideal) and those with (non-ideal) outcome-relevant co-morbidities. Benchmark cut-offs were defined as the 75th percentile of each centre's median value. RESULTS: A total of 3903 patients who underwent HAR and 3726 who had LAR for cancer were analysed. After 3 months' follow-up, the mortality benchmark in HAR for ideal and non-ideal patients was 0.0 versus 3.0 per cent, and in LAR it was 0.0 versus 2.2 per cent. Benchmark results for anastomotic leakage were 5.0 versus 6.9 per cent for HAR, and 13.6 versus 11.8 per cent for LAR. The overall morbidity benchmark in HAR was a Comprehensive Complication Index (CCI®) score of 8.6 versus 14.7, and that for LAR was CCI® score 11.9 versus 18.3. CONCLUSION: Regular comparison of individual-surgeon or -unit outcome data against benchmark thresholds may identify gaps in care quality that can improve patient outcome.

Utilising quality of life outcome trajectories to aid patient decision making in pelvic exenteration.

BACKGROUND: Shared decision-making in pelvic exenteration is a complex and detailed process, which must balance clinical, oncological and patient-reported outcomes (PROs), whilst addressing and valuing the patient priorities. Communicating patient-centred information on quality of life (QoL) and functional outcomes is an essential component of this. The aim of this systematic review was to understand the impact of pelvic exenteration on QoL PROs over a longitudinal period and to develop QoL trajectories to support decision-making in this context. METHODS: MEDLINE, Embase and Web of Science databases were searched between 1st January 2000 and 20th December 2021 Studies reporting on PROs, including QoL, in adults undergoing pelvic exenteration were included. Risk of bias was assessed using the ROBINS-I assessment tool. Data from studies reporting QoL using the same outcome measure at the same candidate timepoint were extracted and synthesised to develop a longitudinal QoL trajectory. RESULTS: Fourteen studies consisting of 1370 patients were included in this review. QoL trajectories were constructed in the domains of physical function, psychological function, role function, sexual function, body image and general and specific symptoms. Decision-making was only assessed by one study, with satisfaction with decision-making reported to be high. There is an initial decline in QoL scores in the domains of physical function, role function, sexual function, body image and general health and symptoms deteriorating during the first 3-6 months post-operatively. Psychological function is the only QoL domain that remains stable throughout the post-operative period. CONCLUSION: Mapping QoL trajectories provides a visual representation of post-operative progress, highlighting the enduring impact of pelvic exenteration on patients and can be used to inform pre-operative shared decision-making.

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.

Assessment of the 2020 NICE criteria for preoperative radiotherapy in patients with rectal cancer treated by surgery alone in comparison with proven MRI prognostic factors: a retrospective cohort study.

BACKGROUND: Selection of patients for preoperative treatment in rectal cancer is controversial. The new 2020 National Institute for Health and Care Excellence (NICE) guidelines, consistent with the National Comprehensive Cancer Network guidelines, recommend preoperative radiotherapy for all patients except for those with radiologically staged T1-T2, N0 tumours. We aimed to assess outcomes in non-irradiated patients with rectal cancer and to stratify results on the basis of NICE criteria, compared with known MRI prognostic factors now omitted by NICE. METHODS: For this retrospective cohort study, we identified patients undergoing primary resectional surgery for rectal cancer, without preoperative radiotherapy, at Basingstoke Hospital (Basingstoke, UK) between Jan 1, 2011, and Dec 31, 2016, and at St Marks Hospital (London, UK) between Jan 1, 2007, and Dec 31, 2017. Patients with MRI-detected extramural venous invasion, MRI-detected tumour deposits, and MRI-detected circumferential resection margin involvement were categorised as MRI high-risk for recurrence (local or distant), and their outcomes (disease-free survival, overall survival, and recurrence) were compared with patients defined as high-risk according to NICE criteria (MRI-detected T3+ or MRI-detected N+ status). Kaplan-Meier and Cox proportional hazards analyses were used to compare the groups. FINDINGS: 378 patients were evaluated, with a median of 66 months (IQR 44-95) of follow up. 22 (6%) of 378 patients had local recurrence and 68 (18%) of 378 patients had distant recurrence. 248 (66%) of 378 were classified as high-risk according to NICE criteria, compared with 121 (32%) of 378 according to MRI criteria. On Kaplan-Meier analysis, NICE high-risk patients had poorer 5-year disease-free survival compared with NICE low-risk patients (76% [95% CI 70-81] vs 87% [80-92]; hazard ratio [HR] 1·91 [95% CI 1·20-3·03]; p=0·0051) but not 5-year overall survival (80% [74-84] vs 88% [81-92]; 1·55 [0·94-2·53]; p=0·077). MRI criteria separated patients into high-risk versus low-risk groups that predicted 5-year disease-free survival (66% [95% CI 57-74] vs 88% [83-91]; HR 3·01 [95% CI 2·02-4·47]; p<0·0001) and 5-year overall survival (71% [62-78] vs 89% [84-92]; 2·59 [1·62-3·88]; p<0·0001). On multivariable analysis, NICE risk assessment was not associated with either disease-free survival or overall survival, whereas MRI criteria predicted disease-free survival (HR 2·74 [95% CI 1·80-4·17]; p<0·0001) and overall survival (HR 2·44 [95% CI 1·51-3·95]; p=0·00027). 139 NICE high-risk patients who were defined as low-risk based on MRI criteria had similar disease-free survival as 118 NICE low-risk patients; therefore, 37% (139 of 378) of patients in this study cohort would have been overtreated with NICE 2020 guidelines. Of the 130 patients defined as low-risk by NICE guidelines, 12 were defined as high-risk on MRI risk stratification and would have potentially been missed for treatment. INTERPRETATION: Compared to previous guidelines, implementation of the 2020 NICE guidelines will result in significantly more patients receiving preoperative radiotherapy. High-quality MRI selects patients with good outcomes (particularly low local recurrence) without radiotherapy, with little margin for improvement. Overuse of radiotherapy could occur with this unselective approach. The high-risk group, with the most chance of benefiting from preoperative radiotherapy, is not well selected on the basis of NICE 2020 criteria and is better identified with proven MRI prognostic factors (extramural venous invasion, tumour deposits, and circumferential resection margin). FUNDING: None.

Systematic Review: The Impact and Importance of Body Composition in Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Alterations in body composition are common in inflammatory bowel disease [IBD] and have been associated with differences in patient outcomes. We sought to consolidate knowledge on the impact and importance of body composition in IBD. METHODS: We performed a systematic search of MEDLINE, EMBASE and conference proceedings by combining two key research themes: inflammatory bowel disease and body composition. RESULTS: Fifty-five studies were included in this review. Thirty-one focused on the impact of IBD on body composition with a total of 2279 patients with a mean age 38.4 years. Of these, 1071 [47%] were male. In total, 1470 [64.5%] patients had Crohn's disease and 809 [35.5%] had ulcerative colitis. Notably, fat mass and fat-free mass were reduced, and higher rates of sarcopaenia were observed in those with active IBD compared with those in clinical remission and healthy controls. Twenty-four additional studies focused on the impact of derangements in body composition on IBD outcomes. Alterations in body composition in IBD are associated with poorer prognoses including higher rates of surgical intervention, post-operative complications and reduced muscle strength. In addition, higher rates of early treatment failure and primary non-response are seen in patients with myopaenia. CONCLUSIONS: Patients with IBD have alterations in body composition parameters in active disease and clinical remission. The impacts of body composition on disease outcome and therapy are broad and require further investigation. The augmentation of body composition parameters in the clinical setting has the potential to improve IBD outcomes in the future.

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.

Laparoscopic Colorectal Surgery Outcomes Improved After National Training Program (LAPCO) for Specialists in England.

OBJECTIVE: To examine the impact of The National Training Program for Lapco on the rate of laparoscopic surgery and clinical outcomes of cases performed by Lapco surgeons after completion of training. SUMMARY OF BACKGROUND DATA: Lapco provided competency-based supervised clinical training for specialist colorectal surgeons in England. METHODS: We compared the rate of laparoscopic surgery, mortality, and morbidity for colorectal cancer resections by Lapco delegates and non-Lapco surgeons in 3-year periods preceding and following Lapco using difference in differences analysis. The changes in the rate of post-Lapco laparoscopic surgery with the Lapco sign-off competency assessment and in-training global assessment scores were examined using risk-adjusted cumulative sum to determine their predictive clinical validity with predefined competent scores of 3 and 5 respectively. RESULTS: One hundred eight Lapco delegates performed 4586 elective colo-rectal resections pre-Lapco and 5115 post-Lapco while non-Lapco surgeons performed 72,930 matched cases. Lapco delegates had a 37.8% increase in laparoscopic surgery which was greater than non-Lapco surgeons by 20.9% [95% confidence interval (CI), 18.5-23.3, P < 0.001) with a relative decrease in 30-day mortality by -1.6% (95% CI, -3.4 to -0.2, P = 0.039) and 90-day mortality by -2.3% (95% CI, -4.3 to -0.4, P = 0.018). The change point of risk-adjusted cumulative sum was 3.12 for competency assessment tool and 4.74 for global assessment score whereas laparoscopic rate increased from 44% to 66% and 40% to 56%, respectively. CONCLUSIONS: Lapco increased the rate of laparoscopic colorectal cancer surgery and reduced mortality and morbidity in England. In-training competency assessment tools predicted clinical performance after training.

Empty pelvis syndrome: a systematic review of reconstruction techniques and their associated complications.

AIM: Empty pelvis syndrome is a major contributor to morbidity following pelvic exenteration. Several techniques for filling the pelvis have been proposed; however, there is no consensus on the best approach. We evaluated and compared the complications associated with each reconstruction technique with the aim of determining which is associated with the lowest incidence of complications related to the empty pelvis. METHOD: The systematic review protocol was prospectively registered with PROSPERO (CRD42021239307). PRISMA-P guidelines were used to present the literature. PubMed and MEDLINE were systematically searched up to 1 February 2021. A dataset containing predetermined primary and secondary outcomes was extracted. RESULTS: Eighteen studies fulfilled our criteria; these included 375 patients with mainly rectal and gynaecological cancer. Only three studies had a follow-up greater than 2 years. Six surgical interventions were identified. Mesh reconstruction and breast prosthesis were associated with low rates of small bowel obstruction (SBO), entero-cutaneous fistulas and perineal hernia. Findings for myocutaneous flaps were similar; however, they were associated with high rates of perineal wound complications. Omentoplasty was found to have a high perineal wound infection rate (40%). Obstetric balloons were found to have the highest rates of perineal wound dehiscence and SBO. Silicone expanders effectively kept small bowel out of the pelvis, although rates of pelvic collections remained high (20%). CONCLUSION: The morbidity associated with an empty pelvis remains considerable. Given the low quality of the evidence with small patient numbers, strong conclusions in favour of a certain technique and comparison of these interventions remains challenging.