Current and future genomic applications for surgeons

Genomics is a crucial part of managing surgical disease. This review focuses on some of the genomic advances that are available now and looks to the future of their application in surgical practice. Whole-genome sequencing enables unbiased coverage across the entire human genome of approximately three billion base pairs. Newer technologies, such as those that permit long-read sequence analysis, provide additional information in longer phased fragment and base pair epigenomic (methylomic) data. Whole-genome sequencing is currently available in England for cancers in children, teenagers and young adults, central nervous system tumours, sarcoma and haematological malignancies. Circulating tumour DNA (ctDNA), immunotherapy and pharmacogenomics have emerged as groundbreaking approaches in the field of cancer treatment. These are now revolutionising the way oncologists and surgeons approach curative cancer surgery. Cancer vaccines offer an innovative approach to reducing recurrence after surgery by priming the immune system to trigger an immune response. The Cancer Vaccine Launch Pad project facilitates cancer vaccine studies in England. The BNT122-01 trial is recruiting patients with ctDNA-positive high-risk colorectal cancer after surgery to assess the impact of cancer vaccines. The evolving landscape of cancer treatment demands a dynamic and integrated approach from the surgical multidisciplinary team. Immunotherapy, ctDNA, pharmacogenomics, vaccines, mainstreaming and whole-genome sequencing are just some of the innovations that have the potential to redefine the standards of care. The continued exploration of these innovative diagnostics and therapies, the genomic pathway evolution and their application in diverse cancer types highlights the transformative impact of precision medicine in surgery.

The empty pelvis syndrome: a core data set from the PelvEx collaborative

BACKGROUND

Empty pelvis syndrome (EPS) is a significant source of morbidity following pelvic exenteration (PE), but is undefined. EPS outcome reporting and descriptors of radicality of PE are inconsistent; therefore, the best approaches for prevention are unknown. To facilitate future research into EPS, the aim of this study is to define a measurable core outcome set, core descriptor set and written definition for EPS. Consensus on strategies to mitigate EPS was also explored.

METHOD

Three-stage consensus methodology was used: longlisting with systematic review, healthcare professional event, patient engagement, and Delphi-piloting; shortlisting with two rounds of modified Delphi; and a confirmatory stage using a modified nominal group technique. This included a selection of measurement instruments, and iterative generation of a written EPS definition.

RESULTS

One hundred and three and 119 participants took part in the modified Delphi and consensus meetings, respectively. This encompassed international patient and healthcare professional representation with multidisciplinary input. Seventy statements were longlisted, seven core outcomes (bowel obstruction, enteroperineal fistula, chronic perineal sinus, infected pelvic collection, bowel obstruction, morbidity from reconstruction, re-intervention, and quality of life), and four core descriptors (magnitude of surgery, radiotherapy-induced damage, methods of reconstruction, and changes in volume of pelvic dead space) reached consensus-where applicable, measurement of these outcomes and descriptors was defined. A written definition for EPS was agreed.

CONCLUSIONS

EPS is an area of unmet research and clinical need. This study provides an agreed definition and core data set for EPS to facilitate further research.

Clinical management of high-output stoma: a systematic literature review and meta-analysis

PURPOSE

High output is a common complication after stoma formation. Although the management of high output is described in the literature, there is a lack of consensus on definitions and treatment. Our aim was to review and summarise the current best evidence.

METHODS

MEDLINE, Cochrane Library, BNI, CINAHL, EMBASE, EMCARE, and ClinicalTrials.gov were searched from 1 Jan 2000 to 31 Dec 2021 for relevant articles on adult patients with a high-output stoma. Patients with enteroatmospheric fistulas and case series/reports were excluded. Risk of bias was assessed using RoB2 and MINORS. The review was registered in PROSPERO (CRD42021226621).

RESULTS

The search strategy identified 1095 articles, of which 32 studies with 768 patients met the inclusion criteria. These studies comprised 15 randomised controlled trials, 13 non-randomised prospective trials, and 4 retrospective cohort studies. Eighteen different interventions were assessed. In the meta-analysis, there was no difference in stoma output between controls and somatostatin analogues (g - 1.72, 95% CI - 4.09 to 0.65, p = 0.11, I2 = 88%, t2 = 3.09), loperamide (g - 0.34, 95% CI - 0.69 to 0.01, p = 0.05, I2 = 0%, t2 = 0) and omeprazole (g - 0.31, 95% CI  - 2.46 to 1.84, p = 0.32, I2 = 0%, t2 = 0). Thirteen randomised trials showed high concern of bias, one some concern, and one low concern. The non-randomised/retrospective trials had a median MINORS score of 12 out of 24 (range 7-17).

CONCLUSION

There is limited high-quality evidence favouring any specific widely used drug over the others in the management of high-output stoma. Evidence, however, is weak due to inconsistent definitions, risk of bias and poor methodology in the existing studies. We recommend the development of validated core descriptor and outcomes sets, as well as patient-reported outcome measures.

The impact of a dedicated social media strategy on enhancing surgical education

PURPOSE

Social media (SoMe) is increasingly important in surgical education and may be necessary in the current learning environment. Whilst expanding in use and applications, few studies detail the impact of SoMe on measurable outcomes. The goal of this study was to quantify the impact of a dedicated SoMe strategy on engagement metrics for surgical research.

METHODS

A retrospective review of a peer-reviewed surgical journal's Twitter microblog platform (@ColorectalDis) was performed from 6/2015 to 4/2021. A formal SoMe strategy was introduced in September 2018. Data were stratified into 2 time periods: pre-intervention (6-2015 to 9-2018) and post-SoMe intervention (9-2018 to 4-2021). The main outcome was the impact of the SoMe strategy on user engagement with the Twitter platform, journal, and traditional journal metrics. Twitter Analytics and Twitonomy were used to analyse engagement.

RESULTS

From conception to analysis, the microblog published 1198 original tweets, generating 5 million impressions and 231,000 engagements. Increased account activity (increased tweets published per month-5.51 vs 28.79; p < 0.01) was associated with significant engagement growth, including new monthly followers (213 vs 38; p < 0.01) and interactions with posted articles (4,096,167 vs 269,152; p < 0.01). Article downloads increased twenty-fold post-SoMe intervention (210,449 vs 10,934; p < 0.01), with significant increases in traditional journal metrics of new subscribers (+11%), article submissions (+24%), and impact factor (+0.9) (all p < 0.01).

CONCLUSION

SoMe directly impacts traditional journal metrics in surgical research. By examining the patterns of user engagement between SoMe and journal sites, the growing beneficial impact of a structured social media strategy and SoMe as an educational tool is demonstrated.

Outcomes of patients with non-lower gastrointestinal cancer diagnosed via the lower gastrointestinal two-week-wait service

INTRODUCTION

Patients referred via lower gastrointestinal two-week-wait (LGI-2WW) services deemed at 'low risk' of LGI cancer may have delayed or no investigation. However, 20% of patients diagnosed with cancer via the LGI-2WW have non-LGI cancer. This study investigates the outcomes in this under-reported group.

METHODS

A retrospective analysis of patients referred to a UK LGI-2WW service with a non-LGI cancer diagnosis (International Classification of Diseases 10th revision) between 1 January 2015 and 31 December 2018. The primary outcome was all-cause mortality. Statistical analysis was undertaken using Kaplan-Meier survival curves with generalised log-rank test and binomial logistic regression of pre-investigation information to predict death. A p-value of < 0.05 represented statistical significance.

RESULTS

In total, 140 patients were diagnosed with non-LGI cancer (of 10,155 patients referred via the LGI-2WW pathway). Median follow-up was 13 months (range 0-65 months). Thirty-five patients (35/140; 25%) did not meet LGI-2WW referral criteria. Median survival varied by cancer site (upper gastrointestinal: 43/140 patients, median survival 4 months; gynaecological: 25/140, 25 months; haematological: 22/140, < 50% died; urological: 21/140, 47 months; unknown primary: 12/140, 3 months; lung: 10/140, 17 months; breast: 3/140, 5 months; retroperitoneal: 2/140, 9 months; brain: 1/140, 4 months; adrenal: 1/140, 52 months). Binomial logistic regression was statistically significant (chi-squared goodness-of-fit test = 12.334; p = 0.03); but the presence of comorbidity was the only significant predictive factor of death (p = 0.03).

CONCLUSIONS

Patients with non-LGI cancers cannot be easily predicted and have a poor prognosis. Pathways to streamline investigations for LGI cancer should include computed tomography scans for patients at 'low risk' of LGI cancer to ensure that non-LGI cancers are diagnosed.

Minimum standards of pelvic exenterative practice: PelvEx Collaborative guideline

This document outlines the important aspects of caring for patients who have been diagnosed with advanced pelvic cancer. It is primarily aimed at those who are establishing a service that adequately caters to this patient group. The relevant literature has been summarized and an attempt made to simplify the approach to management of these complex cases.

Survival outcomes of elderly patients referred to the lower gastrointestinal 2-week wait service

AIM

The benefit to elderly patients (≥80 years old) of referral to the resource-intensive lower gastrointestinal 2-week wait (LGI-2WW) pathway is unknown. The aim of this study was to investigate the survival outcome of elderly patients referred to a LGI-2WW service.

METHOD

This study comprised a retrospective analysis of a prospectively gathered database of patients referred to a single-centre LGI-2WW service and conformed to STROBE guidelines. The primary outcome was all-cause mortality. Statistical analysis was performed with the chi-square test and Kaplan-Meier survival curves compared with the generalized log-rank test.

RESULTS

A total of 10 155 patients referred to the LGI-2WW service between 1 January 2015 and 31 December 2018 were analysed; median follow-up was 37.0 months (range 0-66 months). Six hundred and ninety one cancers were diagnosed (6.8% detection rate); 551 (80%) of these were lower GI cancers (LGICas) [517 (75%) colorectal; 34 (5%) anal]. Forty per cent of LGICas were diagnosed via the LGI-2WW service. Patients aged ≥80 years with LGICa were more likely to be treated with palliative intent [age <80 years, 92/360 (26%) vs. age ≥80 years, 105/191 (55%); p < 0.001]. LGICa patients aged <85 years had a survival difference between those treated with curative intent (LGICa-Cur) or palliative intent (LGICa-Pal) (median survival for patients aged 80-84 years: LGICa-Cur 57 months vs. LGICa-Pal 15 months; p < 0.001). Patients aged ≥85 years did not have any survival difference by treatment intent (median survival for patients aged 85-89 years: LGICa-Cur 31 months vs. LGICa-Pal 16 months; p = 0.062; median survival for patients aged ≥90 years: LGICa-Cur 14 months vs. LGICa-Pal 16 months; p = 0.703).

CONCLUSION

Patients with LGICa aged ≥85 years have similar survival whether treated with curative or palliative intent. This can inform management discussions with patients and LGI-2WW referral pathway prioritization approaches.

Implications for the colorectal surgeon following the 100 000 Genomes Project

AIM

The 100 000 Genomes Project was completed in 2019 with the objective of integrating genomic medicine into routine National Health Service (NHS) clinical pathways. This project and genomic research will revolutionize the way we practice colorectal surgery in the 21st century. This paper aims to provide an overview of genomic medicine and its implications for the colorectal surgeon.

RESULTS

Within NHS England, consolidation has created seven regional Genomic Laboratory Hubs. DNA from solid tumours, including colorectal cancers, will be assessed using 500-gene panels, results will be fed back to Genome Tumour Advisory Boards. Identifying variants from biopsies earlier in the clinical pathway may alter surgical and other treatment options for patients. However, there is an important distinction between somatic variants within a tumour biopsy and germline variants that may suggest a heritable condition such as Lynch syndrome. Novel drugs, for example immunotherapy, will increase treatment options including downstaging cancers and changing the surgical approach. The use of circulating tumour DNA (liquid biopsies) will have applications in diagnosis, treatment and surveillance of cancer. There are many exciting potential future applications of this technology for offering personalized medicine that will require multidisciplinary working and the colorectal community.

CONCLUSION

There are many challenges but also exciting opportunities to embed new 'omic' technologies and innovation into 21st century colorectal surgery. The next phase for the colorectal community is how we engage with this change, with questions around training, identification of genomic multidisciplinary team (MDT) champions and how we collaborate with the core members of the MDT, clinical geneticists and national genomic testing.

Single centre experience of bilateral gracilis flap perineal reconstruction following extra-levator abdominoperineal excision

AIM

A variety of tissue flaps have been described for the closure of perineal wounds following abdominoperineal excision of the rectum (APE) or exenteration for locally advanced/recurrent rectal cancer and salvage surgery for anal cancer. The aim of this study was to demonstrate the utility of the bilateral pedicled gracilis muscle flaps (BPGMFs) as a reconstruction option in these patients. This is of particular benefit when using a laparoscopic approach for the abdominal component of the operation, avoiding disruption of the abdominal wall and risk of herniation with other reconstruction options, e.g. vertical rectus abdominis myocutaneous flaps.

METHOD

This is a retrospective single centre case series of patients who underwent reconstruction of perineal defects using BPGMFs using a novel weave technique, from January 2008 to August 2017.

RESULTS

There were 25 patients (16 female), with a median follow-up of 19 months (3-102). The indications for BPGMFs were cancer resection (21) and perineal hernia (4). The median length of stay was 14 days (6-60). All-cause mortality was 36% within the follow-up period. A healed perineal wound was achieved in 72% of patients within 30 days (84% of patients received neoadjuvant chemoradiotherapy). The overall donor site complication rate was 20% (including infection, dehiscence, numbness, haematoma and seroma) and 28% for the perineal site (including infection, dehiscence and prolapse).

CONCLUSIONS

BPGMFs provide an important option for reconstruction of the perineum particularly with a minimally invasive approach or with two stomas.

Problems and solutions in delivering global surgery in the 21st century

BACKGROUND

Surgery has had low priority in global health planning, so the delivery of surgical care in low- and middle-income countries is often poorly resourced. A recent Lancet Commission on Global Surgery has highlighted the need for change.

METHODS

A consensus view of the problems and solutions was identified by individual surgeons from high-income countries, familiar with surgical care in remote and poorer environments, based on recent publications related to global surgery.

RESULTS

The major issues identified were: the perceived unimportance of surgery, shortage of personnel, lack of appropriate training and failure to establish surgical standards, failure to appreciate local needs and poor coordination of service delivery.

CONCLUSION

Surgery deserves a higher priority in global health resource allocation. Lessons learned from participation in humanitarian crises should be considered in surgical developments.

Gnotobiotic Human Colon Ex Vivo

Background

A novel emulsion with efficacy as an agent for eliminating biofilms was selected. The aim of this study was to examine efficacy and effect of a formulation of ML:8 against commensal bacteria harvested from ex vivo human colonic tissues.

Methods

Mucosal sheets, obtained at the time of surgery, were exposed for 2 minutes to one of four solutions: Krebs-Hensleit (KH) solution, saline (NaCl; 0.9%), povidone iodine (1%), or ML:8 (2%); n = 4. Lumenal surfaces were swabbed for culture under aerobic or anaerobic conditions. Following treatment, each sheet was mounted in Ussing chambers and voltage clamped. Tissues were challenged with carbachol. Permeability coefficient (Papp) was determined using mannitol fluxes. At the end of each experiment, tissues were examined histologically.

Results

Similar colony forming units grew in aerobic and anaerobic conditions in both control and NaCl treated tissues. Iodine reduced and ML:8 virtually abolished viable bacteria. Basal electrophysiological parameters were not different between treatments. Transepithelial electrical resistance values did not differ between groups. All tissues responded to carbachol, although this was attenuated in iodine treated tissue. Papp values were slightly elevated in all treated tissues but this did not reach significance. Histopathological assessment revealed no overt damage to tissues.

Conclusion

Brief exposure to ML:8 reduced culturable bacterial burden from human intestinal tissues harvested at the time of surgical resection. Such gnotobiotic tissues retain structural and functional integrity. This is a novel approach to reduce bacterial burden.

The effects of polyamines on human colonic mucosal function

Electrogenic ion transport in human colon is a surrogate marker for colonic mucosal function, and may be manipulated by a variety of hormonal, neural, immune and paracrine mediators. Polyamines are present in vast quantities in the colonic lumen and appear to be integral to cellular function. This study explores some of the mechanisms of polyamine action on colonic tissue through study of their effects on differential secretory pathways, as well as examining their actions on intracellular cAMP and Ca(2+) accumulation. Human colonic mucosa was mounted in Ussing chambers and treated with polyamines (spermine, spermidine and putrescine) with changes in ion transport recorded. In separate experiments colonic crypts were treated with polyamines and intracellular cAMP levels determined by ELISA and intracellular calcium concentrations were quantified by fluorescent imaging. Polyamines at physiological concentrations (1mM) exert no effects on basal mucosal chloride secretion or transepithelial electrical resistance. Polyamines inhibit electrogenic ion secretion as stimulated by forskolin (cAMP-mediated), but not carbachol (Ach-mediated). All the polyamines used in this study inhibited intracellular cAMP accumulation, according to potency (spermine>spermidine>putrescine). Spermine increased intracellular Ca(2+) in a PKC-dependent manner, likely due to its effects on the extracellular calcium-sensing receptor (CaSR). Polyamines act to prevent cAMP-mediated Cl(-) hypersecretion in the colon, acting through CaSR to inhibit PKC-mediated [Ca(2+)]i release from intracellular stores.

Female gender and diabetes mellitus increase the risk of recurrence after laparoscopic incisional hernia repair

BACKGROUND

Laparoscopic hernia repair is used widely for the repair of incisional hernias. Few case studies have focussed on purely 'incisional' hernias. This multicentre series represents a collaborative effort and employed statistical analyses to provide insight into the factors predisposing to recurrence of incisional hernia after laparoscopic repair. A specific hypothesis (ie, laterality of hernias as well as proximity to the xyphoid process and pubic symphysis predisposes to recurrence) was also tested.

METHODS

This was a retrospective study of all laparoscopic incisional hernias undertaken in six centres from 1 January 2004 to 31 December 2010. It comprised a comprehensive review of case notes and a follow-up using a structured telephone questionnaire. Patient demographics, previous medical/surgical history, surgical procedure, postoperative recovery, and perceived effect on quality of life were recorded. Repairs undertaken for primary ventral hernias were excluded. A logistic regression analysis was then fitted with recurrence as the primary outcome.

RESULTS

A total of 186 cases (91 females) were identified. Median follow-up was 42 months. Telephone interviews were answered by 115/186 (62%) of subjects. Logistic regression analyses suggested that only female sex (odds ratio (OR) 3.53; 95% confidence interval (CI) 1.39-8.97) and diabetes mellitus (3.54; 1-12.56) significantly increased the risk of recurrence. Position of the defect had no statistical effect.

CONCLUSIONS

These data suggest an increased risk of recurrence after laparoscopic incisional hernia repair in females and subjects with diabetes mellitus. These data will help inform surgeons and patients when considering laparoscopic management of incisional hernias. We recommend a centrally hosted, prospectively maintained national/international database to carry out additional research.

Systematic review of preoperative, intraoperative and postoperative risk factors for colorectal anastomotic leaks

BACKGROUND

Anastomotic leak (AL) represents a dreaded complication following colorectal surgery, with a prevalence of 1-19 per cent. There remains a lack of consensus regarding factors that may predispose to AL and the relative risks associated with them. The objective was to perform a systematic review of the literature, focusing on the role of preoperative, intraoperative and postoperative factors in the development of colorectal ALs.

METHODS

A systematic review was performed to identify adjustable and non-adjustable preoperative, intraoperative and postoperative factors in the pathogenesis of AL. Additionally, a severity grading system was proposed to guide treatment.

RESULTS

Of 1707 papers screened, 451 fulfilled the criteria for inclusion in the review. Significant preoperative risk factors were: male sex, American Society of Anesthesiologists fitness grade above II, renal disease, co-morbidity and history of radiotherapy. Tumour-related factors were: distal site, size larger than 3 cm, advanced stage, emergency surgery and metastatic disease. Adjustable risk factors were: smoking, obesity, poor nutrition, alcohol excess, immunosuppressants and bevacizumab. Intraoperative risk factors were: blood loss/transfusion and duration of surgery more than 4 h. Stomas lessen the consequences but not the prevalence of AL. In the postoperative period, CT is the most commonly used imaging tool, with or without rectal contrast, and a C-reactive protein level exceeding 150 mg/l on day 3-5 is the most sensitive biochemical marker. A five-level classification system for AL severity and appropriate management is presented.

CONCLUSION

Specific risk factors and their potential correction or indications for stoma were identified. An AL severity score is proposed to aid clinical decision-making.

Minimally invasive and surgical management strategies tailored to the severity of acute diverticulitis

BACKGROUND

The severity of acute diverticulitis ranges from mild, simple inflammation to pericolic abscesses, or perforation with faeculent peritonitis. Treatment of diverticulitis has evolved towards more conservative and minimally invasive strategies. The aim of this review is to highlight recent concepts and advances in management.

METHODS

A literature review was performed on the electronic databases MEDLINE from PubMed, Embase and the Cochrane Library for publications in English. The keywords 'diverticulitis', 'diverticular' were searched for the past decade (to September 2013).

RESULTS

Diverticulitis occurs frequently in the Western world, but only one in five patients develops complications (such as abscess and perforation) during the first acute presentation. The reported perforation rate is 3.5 per 100,000 population. Based on recent data, including the AVOD and DIVER trials, antibiotic therapy for mild episodes may be unnecessary and outpatient management reasonable in most patients. Antibiotics and admission to hospital is required for complicated diverticulitis confirmed on imaging and for patients with sepsis. Diverticular abscesses (about 5 per cent of patients) may require percutaneous drainage if antibiotics alone fail. Laparoscopic management of non-faecal perforated diverticulitis is feasible in selected patients, and peritoneal lavage in combination with antibiotic therapy may avoid colonic resection and a stoma. However, the collective, published worldwide experience is limited to fewer than 800 patients, and results from ongoing randomized trials (LapLAND, SCANDIV, DILALA and LADIES trials) are needed to inform better decision-making.

CONCLUSION

The treatment of diverticulitis continues to evolve with a trend towards a more conservative and minimally invasive management approach. Judicious use of antibiotics in uncomplicated cases, greater application of laparoscopic techniques, and primary resection and anastomosis are of benefit in selected patients.