Perianal fistulizing Crohn's disease-associated anorectal and fistula cancers: systematic review and expert consensus.

BACKGROUND AND AIMS: Perianal fistulizing Crohn's disease (PFCD)-associated anorectal and fistula cancers are rare but often devastating diagnoses. However, given the low incidence and consequent lack of data and clinical trials in the field, there is little to no guidance on screening and management of these cancers. To inform clinical practice, we developed consensus guidelines on PFCD-associated anorectal and fistula cancers by multidisciplinary experts from the international TOpClass consortium. METHODS: We conducted a systematic review by standard methodology, using the Newcastle-Ottawa Scale quality assessment tool. We subsequently developed consensus statements using a Delphi consensus approach. RESULTS: Of 561 articles identified, 110 were eligible, and 76 articles were included. The overall quality of evidence was low. The TOpClass consortium reached consensus on six structured statements addressing screening, risk assessment, and management of PFCD-associated anorectal and fistula cancers. Patients with longstanding (>10 years) PFCD should be considered at small but increased risk of developing perianal cancer, including squamous cell carcinoma of the anus(SCCA) and anorectal carcinoma. Risk factors for SCCA, notably human papilloma virus (HPV), should be considered. New, refractory, or progressive perianal symptoms should prompt evaluation for fistula cancer. There was no consensus on timing or frequency of screening in patients with asymptomatic perianal fistula. Multiple modalities may be required for diagnosis, including an exam under anesthesia (EUA) with biopsy. Multidisciplinary team efforts were deemed central to the management of fistula cancers. CONCLUSION: Inflammatory bowel disease (IBD) clinicians should be aware of the risk of PFCD-associated anorectal and fistula cancers in all patients with PFCD. The TOpClass consortium consensus statements outlined herein offer guidance in managing this challenging scenario.

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.

Update for surgeons on novel induction treatments for acute severe inflammatory bowel disease associated colitis.

BACKGROUND: The landscape of biologic agents for the treatment of inflammatory bowel disease (IBD) associated colitis is rapidly evolving, requiring surgeons to be up-to-date as part of multi-disciplinary, evidence-based care. An update on novel therapies used to induce remission in IBD-associated colitis is presented. METHODS: A systematic search through Ovid MEDLINE and CENTRAL using a combination of MeSH terms and Boolean operators was conducted. RESULTS: One thousand and twenty articles from which 38 articles were selected for inclusion in this review. Novel agents were trialled as 4th or 5th line treatment following conventional treatment failure. Rates of serious adverse effects were low. Janus kinase (JAK) inhibitors (upadacitinib and tofacitinib) were efficacious in inducing remission in ulcerative colitis, and IL-23p19 inhibitors (mirikizumab, guselkumab, and risankizumab) in Crohn's colitis. Evidence was limited for other drug classes. CONCLUSION: JAK-inhibitors and IL-23p19 inhibitors were found to be the most effective agents for inducting remission following failure of standard of care treatment. A significant proportion of patients did not respond, highlighting the inherent challenge in optimizing treatment for moderate to severe IBD-associated colitis. More robust study designs and comparator trials are required.

The impact of COVID-19 on general surgical trainees' surgical exposure in Australia.

BACKGROUND: The COVID-19 pandemic disrupted the provision of surgical services in Australia. To prepare for a surge of COVID-19 patients, elective surgery was mandatorily reduced or ceased at multiple timepoints in Australian states between 2020 and 2022. Operative exposure is a critical component of surgical training in general surgery, and readiness for practice is an ongoing priority. However, the impact of COVID-19 on operative exposure in Australian General Surgical Trainees (AGST) has not been quantified. METHODS: This study was a retrospective longitudinal cohort study using de-identified operative logbook data for Australian General surgical Trainees (AGST) from the Royal Australasian College of Surgeons (RACS) Morbidity and Audit Logbook Tool (MALT) system between February 2019 and July 2021. Bivariate analysis was used to determine the impact of COVID-19 on general surgical trainees' exposure to operative surgery and trainees' operative autonomy. RESULTS: Data from 1896 unique 6-month training terms and 543 285 surgical cases was included over the data collection period. There was no statistically significant impact of the COVID-19 pandemic on AGST operative exposure to major, minor operations, endoscopies, or operative autonomy. CONCLUSIONS: The impact of COVID-19 on surgical trainees globally has been significant. Although this study does not assess all aspects of surgical training, this data demonstrates that there has not been a significant impact of the pandemic on operative exposure or autonomy of AGST.

Prophylactic negative pressure wound therapy to improve wound healing rates following ileostomy closure: a randomized controlled trial.

BACKGROUND: Reversal of ileostomy is associated with morbidity including wound infection and prolonged wound healing. Negative pressure wound therapy (NPWT) has been shown to reduce time to wound healing by secondary intention. The aim of this study was to determine whether NPWT improved wound healing rates, compared with simple wound dressings, in patients undergoing reversal of ileostomy where the skin wound is closed with a purse-string suture. METHODS: This was a dual-centre, open-label, randomized controlled trial with two parallel intervention arms. Patients undergoing elective loop ileostomy reversal were randomized 1:1 to receive NPWT or simple wound dressings. The primary endpoint of the study was assessment of complete wound healing at day 42 post reversal of ileostomy and the secondary endpoints were patient-reported wound cosmesis using a visual analogue scale and rates of surgical site infection (SSI). RESULTS: The study was conducted from June 2018 to December 2021. The trial was approved by the local ethics committee. We enrolled 40 patients, 20 in each arm. One patient in each arm was lost to follow up. Nine patients (9/19, 47.36%) in the simple dressing group had wound healing vs. 13 patients (13/19, 68.42%) in the NPWT group (P = 0.188). There was no significant difference in patient- reported wound cosmesis or SSI. CONCLUSION: There was no difference in wound healing rates when comparing NPWT to simple wound dressings at early and late time points post reversal of ileostomy, where the skin wound was closed with a purse-string suture.

Pyridostigmine in chronic intestinal pseudo-obstruction - a systematic review.

BACKGROUND: Chronic intestinal pseudo-obstruction (CIPO) may be a primary or secondary phenomenon and is often multifactorial. Treatment is largely directed at improving colonic motility. The use of cholinesterase inhibitors such as pyridostigmine has been hypothesized to increase acetylcholine in the bowel, improving symptoms and transit times. METHODS: A systematic review of the use of pyridostigmine in CIPO was conducted using scientific and commercial search engines identifying scientific studies enrolling adult human subjects, published from 2000 to 2022 in the English language. RESULTS: Four studies were identified including two randomized controlled trials (RCT) and two observational studies. The studies had heterogenous inclusion criteria, dosing regimens and reported outcomes. Two studies were identified as being at high risk of bias. All studies reported improved patient outcomes with use of pyridostigmine, and low rates (4.3%) of mild cholinergic side effects. No major side effects were reported. CONCLUSION: The use of pyridostigmine in management of CIPO is biologically plausible due to its ability to increase colonic motility, and early studies on its role are uniformly suggestive of benefit with low side-effect profile. Four clinical studies have been conducted to date, with small sample sizes, heterogeneity and high risk of bias. Further high-quality studies are required to enable assessment of pyridostigmine's utility as an effective management strategy in CIPO.

Longitudinal Monitoring of Intra-Tumoural Heterogeneity Using Optical Barcoding of Patient-Derived Colorectal Tumour Models.

Geno- and phenotypic heterogeneity amongst cancer cell subpopulations are established drivers of treatment resistance and tumour recurrence. However, due to the technical difficulty associated with studying such intra-tumoural heterogeneity, this phenomenon is seldom interrogated in conventional cell culture models. Here, we employ a fluorescent lineage technique termed "optical barcoding" (OBC) to perform simultaneous longitudinal tracking of spatio-temporal fate in 64 patient-derived colorectal cancer subclones. To do so, patient-derived cancer cell lines and organoids were labelled with discrete combinations of reporter constructs, stably integrated into the genome and thus passed on from the founder cell to all its clonal descendants. This strategy enables the longitudinal monitoring of individual cell lineages based upon their unique optical barcodes. By designing a novel panel of six fluorescent proteins, the maximum theoretical subpopulation resolution of 64 discriminable subpopulations was achieved, greatly improving throughput compared with previous studies. We demonstrate that all subpopulations can be purified from complex clonal mixtures via flow cytometry, permitting the downstream isolation and analysis of any lineages of interest. Moreover, we outline an optimized imaging protocol that can be used to image optical barcodes in real-time, allowing for clonal dynamics to be resolved in live cells. In contrast with the limited intra-tumour heterogeneity observed in conventional 2D cell lines, the OBC technique was successfully used to quantify dynamic clonal expansions and contractions in 3D patient-derived organoids, which were previously demonstrated to better recapitulate the heterogeneity of their parental tumour material. In summary, we present OBC as a user-friendly, inexpensive, and high-throughput technique for monitoring intra-tumoural heterogeneity in in vitro cell culture models.

Survival benefit of neoadjuvant chemotherapy and surgery versus surgery first for resectable colorectal liver metastases: a cohort study.

BACKGROUND: There is continued debate about the survival benefit of neoadjuvant chemotherapy (neoCT) in patients with resectable colorectal liver metastases (CRLM). METHODS: In this retrospective cohort study, we included 201 patients with metastatic colorectal cancer who underwent their first CRLM resection and achieved resection of all sites of disease. We compared the overall survival (OS) and progression-free survival (PFS) between patients who received neoCT prior to CRLM resection with those who underwent CRLM upfront. A multivariable Cox proportional hazard regression analysis was performed to adjust for potential confounders. RESULTS: A total of 101 of 201 (51.2%) patients received chemotherapy prior to CRLM resection and 100 of 201 had surgery upfront. Multivariable Cox proportional hazard regression showed no statistically significant difference in the hazard of death for those given neoCT prior to resection of CRLM compared with surgery first for both OS and PFS (OS: hazard ratio 1.74, 95% confidence interval 0.85-3.55, P = 0.127, PFS: hazard ratio 1.42, 95% confidence interval 0.93-2.19, P = 0.107). CONCLUSION: In our series of patients with metastatic colorectal cancer who achieved surgical resection of all sites of disease, neoCT prior to CRLM resection was not associated with any survival benefit.

The Ratio of Exhausted to Resident Infiltrating Lymphocytes Is Prognostic for Colorectal Cancer Patient Outcome.

Immunotherapy success in colorectal cancer is mainly limited to patients whose tumors exhibit high microsatellite instability (MSI). However, there is variability in treatment outcomes within this group, which is in part driven by the frequency and characteristics of tumor-infiltrating immune cells. Indeed, the presence of specific infiltrating immune-cell subsets has been shown to correlate with immunotherapy response and is in many cases prognostic of treatment outcome. Tumor-infiltrating lymphocytes (TIL) can undergo distinct differentiation programs, acquiring features of tissue-residency or exhaustion, a process during which T cells upregulate inhibitory receptors, such as PD-1, and lose functionality. Although residency and exhaustion programs of CD8+ T cells are relatively well studied, these programs have only recently been appreciated in CD4+ T cells and remain largely unknown in tumor-infiltrating natural killer (NK) cells. In this study, we used single-cell RNA sequencing (RNA-seq) data to identify signatures of residency and exhaustion in colorectal cancer-infiltrating lymphocytes, including CD8+, CD4+, and NK cells. We then tested these signatures in independent single-cell data from tumor and normal tissue-infiltrating immune cells. Furthermore, we used versions of these signatures designed for bulk RNA-seq data to explore tumor-intrinsic mutations associated with residency and exhaustion from TCGA data. Finally, using two independent transcriptomic datasets from patients with colon adenocarcinoma, we showed that combinations of these signatures, in particular combinations of NK-cell activity signatures, together with tumor-associated signatures, such as TGFß signaling, were associated with distinct survival outcomes in patients with colon adenocarcinoma.

A thiol-bound drug reservoir enhances APR-246-induced mutant p53 tumor cell death.

The tumor suppressor gene TP53 is the most frequently mutated gene in cancer. The compound APR-246 (PRIMA-1Met/Eprenetapopt) is converted to methylene quinuclidinone (MQ) that targets mutant p53 protein and perturbs cellular antioxidant balance. APR-246 is currently tested in a phase III clinical trial in myelodysplastic syndrome (MDS). By in vitro, ex vivo, and in vivo models, we show that combined treatment with APR-246 and inhibitors of efflux pump MRP1/ABCC1 results in synergistic tumor cell death, which is more pronounced in TP53 mutant cells. This is associated with altered cellular thiol status and increased intracellular glutathione-conjugated MQ (GS-MQ). Due to the reversibility of MQ conjugation, GS-MQ forms an intracellular drug reservoir that increases availability of MQ for targeting mutant p53. Our study shows that redox homeostasis is a critical determinant of the response to mutant p53-targeted cancer therapy.

Molecular and genomic characterisation of a panel of human anal cancer cell lines.

Anal cancer is a rare disease that has doubled in incidence over the last four decades. Current treatment and survival of patients with this disease has not changed substantially over this period of time, due, in part, to a paucity of preclinical models to assess new therapeutic options. To address this hiatus, we set-out to establish, validate and characterise a panel of human anal squamous cell carcinoma (ASCC) cell lines by employing an explant technique using fresh human ASCC tumour tissue. The panel of five human ASCC cell lines were validated to confirm their origin, squamous features and tumourigenicity, followed by molecular and genomic (whole-exome sequencing) characterisation. This panel recapitulates the genetic and molecular characteristics previously described in ASCC including phosphoinositide-3-kinase (PI3K) mutations in three of the human papillomavirus (HPV) positive lines and TP53 mutations in the HPV negative line. The cell lines demonstrate the ability to form tumouroids and retain their tumourigenic potential upon xenotransplantation, with varied inducible expression of major histocompatibility complex class I (MHC class I) and Programmed cell death ligand 1 (PD-L1). We observed differential responses to standard chemotherapy, radiotherapy and a PI3K specific molecular targeted agent in vitro, which correlated with the clinical response of the patient tumours from which they were derived. We anticipate this novel panel of human ASCC cell lines will form a valuable resource for future studies into the biology and therapeutics of this rare disease.

Local anaesthesia for haemorrhoidal rubber band ligation reduces immediate post-operative recovery time and use of opioid analgesia.

BACKGROUND: Haemorrhoidal rubber band ligation (RBL) is a well-established, safe and cost-effective treatment for bleeding haemorrhoids. It is generally well tolerated; however, some patients may require narcotic analgesia or even admission to hospital for pain management. This comparative cohort study reports on the difference in peri-procedural analgesia administration and post-operative recovery time between patients who received local anaesthetic (LA) infiltration in addition to RBL, compared with patients treated only with RBL. METHODS: Consecutive patients with haemorrhoids treated over a 3-month period with LA infiltration in addition to RBL were compared to a consecutive control group who received RBL alone in the preceding 3 months. Clinical data were collected prospectively for LA group and retrospectively for the control group. Data collected included analgesia administered during the procedure and in recovery, as well as the mean time to discharge. RESULTS: A total of 32 patients treated with LA infiltration following RBL for haemorrhoids were compared with 22 patients who were treated with RBL alone. There was a reduction in the administration of intra-procedural parecoxib in the LA group (P < 0.001). Following the procedure, there was a reduction in the administration of both oral and intravenous opioid analgesia (P = 0.009) and reduced mean time to discharge in the LA group (P < 0.001). CONCLUSION: Infiltration of LA proximal to the band following RBL for haemorrhoids reduced the administration of analgesia both during the procedure and in recovery, as well as mean time to discharge following the procedure.

Laminin 521 enhances self-renewal via STAT3 activation and promotes tumor progression in colorectal cancer.

Remodeling of basement membrane proteins contributes to tumor progression towards the metastatic stage. One of these proteins, laminin 521 (LN521), sustains embryonic and induced pluripotent stem cell self-renewal, but its putative role in cancer is poorly described. In the present study we found that LN521 promotes colorectal cancer (CRC) cell self-renewal and invasion. siRNA-mediated knockdown of endogenously-produced laminin alpha 5, as well as treatment with neutralizing antibodies against integrin α3ß1 and α6ß1, were able to reverse the effect of LN521 on self-renewal. Exposure of CRC cells to LN521 enhanced STAT3 phosphorylation, and incubation with STAT3 inhibitors Napabucasin and Stattic was sufficient to block the LN521-driven self-renewal increase. Robust expression of laminin alpha 5 was detected in 7/10 liver metastases tissue sections collected from CRC patients as well as in mouse liver metastasis xenografts, in most cases within areas expressing metastasis cancer stem cell markers such as c-KIT and CD44v6. Finally, retrospective analysis of multiple CRC datasets highlighted the significant association between high LN521 mRNA expression and poor clinical outcome in colorectal cancer patients. Collectively our results indicate that high Laminin 521 expression is a frequent feature of metastatic dissemination in CRC and that it promotes cell invasion and self-renewal, the latter through engagement of integrin isoforms and activation of STAT3 signaling.

Three-point stapled fixation technique to manage ileostomy spout retraction.

This paper details a technique to manage non-fixed stomal retraction using a using a non-cutting linear stapler.