Mechanical bowel preparation with pre-operative oral antibiotics in elective colorectal resections: an Australian single institution experience

BACKGROUND

Anastomotic leaks (AL) and surgical site infections (SSI) are serious complications after colorectal resection. Studies have shown the benefits of pre-operative oral antibiotics (OAB) with mechanical bowel preparation (MBP) in reducing AL and SSI rates. We aim to investigate our experience with the short-term outcomes of AL and SSI following elective colorectal resections in patients receiving OAB with MBP versus MBP only.

METHODS

A retrospective analysis was performed from our database for patients who underwent elective colorectal resection between January 2019 and November 2021. Prior to August 2020, OAB was not used as part of MBP. After 2020, Neomycin and Metronidazole were used in conjunction with MBP. We evaluated differences in AL and SSI between both groups.

RESULTS

Five hundred and seventeen patients were included from our database with 247 having MBP while 270 had OAB and MBP. There was a significantly lower rate of AL in patients receiving MBP and OAB as compared to MBP alone (0.4% versus 3.0%, P-value = 0.03). The SSI rate at our institution was 4.4%. It was lower in patients with MBP and OAB as compared to MBP alone, but this was not clinically significant (3.3% versus 5.7%, P-value = 0.19).

CONCLUSION

The association in the reduction of AL with the addition of OAB to the MBP protocol seen here reinforces the need for future randomized controlled trials in the Australasian context. We recommend colorectal institutions in Australian and New Zealand consider OAB with MBP as part of their elective colorectal resection protocol.

Surgical management of splenic flexure cancer: is there an optimal technique? A bi-national registry analysis

BACKGROUND

Splenic flexure tumours (SFC) are uncommon and present at more advanced disease stages. The optimal surgical technique for SFC remains controversial. We sought to compare the short-term outcomes of a left hemicolectomy (LHC) versus an extended resection (subtotal colectomy, STC) for SFCs.

METHODS

A retrospective analysis using the Binational Colorectal Cancer Audit (BCCA) registry was performed. All patients with SFC who underwent elective or emergency surgery for a SFC between 2010 and 2021 were included. Primary outcomes included short-term inpatient complications. Secondary outcomes included survival outcomes.

RESULTS

Six hundred and ninety-nine patients underwent resections for SFCs. A LHC was more common, performed in 64.1%. Patients having a LHC were significantly older, with proportionally more LHCs done laparoscopically. Overall grade III/IV complications were similar between both operations. Prolonged ileus and return to theatre were significantly higher in patients undergoing a STC. On multivariate analysis, anastomotic leak and overall grade III/IV complications were not independently associated with the type of operation. There was no difference in medial survival based on type of operation. Higher tumour stage (Stage III/IV) were independently associated with worse survival.

CONCLUSION

Segmental and extended resections are both oncologically sound procedures for SFCs. Segmental resections are associated with lower rates of prolonged ileus.

Right hemicolectomy for colon cancer: does the anastomotic configuration affect short-term outcomes?

OBJECTIVES

Right hemicolectomy is a common colorectal operation for resection of cancers of the right colon. The ileocolic anastomosis may be created using a stapled end-to-side, stapled side-to-side or handsewn technique. Anastomotic leak and post-operative bleeding are uncommon but serious causes of morbidity and mortality, while post-operative ileus contributes to prolonged length of stay. The aim of this study was to evaluate differences in short-term outcomes between different anastomotic configurations following right hemicolectomy for colon cancer.

METHODS

We conducted a retrospective study using data from the Bowel Cancer Outcomes Registry (BCOR), including 94 hospitals across Australia and New Zealand, of all patients who underwent right hemicolectomy or extended right hemicolectomy for colon cancer with formation of a primary anastomosis between 2007 and 2021.

RESULTS

We included 8164 patients in the analysis. There was no significant difference in rates of anastomotic leak and anastomotic bleeding based on anastomotic technique. A stapled end-to-side anastomosis was associated with a lower rate of post-operative ileus than stapled side-to-side anastomosis (6.5% vs. 7.2%; P = 0.03).

CONCLUSION

Both handsewn and stapled anastomosis techniques may be utilized for oncologic right hemicolectomy, with comparable rates of anastomotic leak and post-operative bleeding. Stapled end-to-side anastomosis resulted in lower rates of prolonged ileus compared to stapled side-to-side anastomoses.

Does intra-operative humidification with warmed CO2 reduce surgical site infection in open colorectal surgery? A randomized control trial

BACKGROUNDS

Surgical site infections (SSI) are a significant cause of postoperative morbidity and mortality, contributing to a considerable financial burden on the healthcare system. Insufflation of the open surgical wound with warm, humidified carbon dioxide (CO₂ ) is a novel measure aimed to reduce SSI. The local atmosphere of warm, humidified CO₂ within the open surgical wound is proposed to decrease airborne contamination, bacterial growth, desiccation, and heat loss while improving tissue oxygenation and perfusion. This randomized controlled trial evaluates the impact of the HumiGard™ surgical humidification system on the incidence of SSI in patients undergoing open colorectal surgery.

METHODS

We conducted a multi-site single-blinded randomized control trial on patients undergoing elective or emergency laparotomy at a single tertiary Colorectal Surgery service. The primary outcome measure was the incidence of SSI, with secondary outcomes including ICU length of stay (LOS), total LOS and mean core temperature.

RESULTS

Patients who received HumiGard™ had a lower incidence of SSI, although this did not reach statistical significance (4.5% for treatment group versus 13.0% for control group; P = 0.092). There was no significant difference in ICU LOS or total LOS between cohorts. The HumiGard™ group had a higher mean core temperature than the control at the end of surgery (P < 0.001).

CONCLUSION

The present study could not confirm that utilization of warm, humidified CO2 with HumiGard™ reduces SSI in open colorectal surgery. Further research is indicated to validate and extend these findings.

Radical vs. Local Excision in Rectal Carcinoma T1N0M0: Recurrence and Mortality Rates

Local transanal excision of early rectal carcinoma is an appealing treatment because of its low morbidity rates and better functional results than radical resection. However, this treatment approach is controversial due to its association with local recurrence when compared to the latter. This review aims to compare the local recurrence and mortality rates of local vs. radical excision in patients with T1N0M0 rectal carcinoma, based on data in the literature in the last 20 years. A PubMed, Cochrane, and Google Scholar search of published literature in the last 20 years was performed. A total of 12 studies were identified. Three were prospective, one was a population-based propensity matching study, one was a nationwide cohort study, one was a meta-analysis, and the remaining studies were retrospective/observational. The mean local recurrence rate within five years from the studies selected for local excision (LE: 12.8%) was nearly double that of radical excision (RAD: 5.0%). The five-year mean survival rate for both LE and RAD groups from the studies selected was 86%, which was equal for both groups. The main predictors of poor outcomes were older age and the presence of two or more comorbid conditions. There is a consensus amongst studies that LE is associated with inferior oncological outcomes such as postoperative complications and recurrence when compared to RAD. The higher local recurrence rates in LE are attributed to occult lymph node disease and inadequate adjunctive therapy due to suboptimal staging. There is no difference in the five-year survival rate when compared to RAD. A longer follow-up period is needed to determine whether the survival rates diverge after five years.

Is colorectal cancer associated with altered bowel habits in young patients?

BACKGROUND

There is a rising incidence in young-onset colorectal cancer, with these patients falling outside of routine screening programmes. The aim of the study is to characterize the nature of altered bowel habits in young patients who are diagnosed with colorectal cancer.

METHODS

A retrospective audit was conducted of adult patients younger than 45 years admitted under a Colorectal Surgery unit (Dandenong Hospital, Victoria) from 2011 to 2019 for the resection of colorectal cancer. We compared the patients' self-characterization of their bowel habits (from the medical record) with clinical and pathological data.

RESULTS

A total of 75 patients were identified, aged between 18 and 45 years, who had surgical resection of colonic or rectal adenocarcinoma between 2011 and 2019. Forty-two (56%) presented with altered bowel habit (irregular bowel habit n = 13, 17%; constipation n = 13, 17%; diarrhoea n = 23, 31%). Constipation approached significance in association with left-sided colonic cancer. Fatigue approached significance in association with right-sided colonic cancers, which were less likely to present with bleeding or constipation, and approached significance in being less likely to present with diarrhoea. Rectal cancers were more likely to present with bleeding.

CONCLUSION

Constipation was associated with left-sided colonic cancers, while right-sided colonic cancers were less likely to present with either constipation or diarrhoea. Our findings reinforce the need for clinicians to consider colorectal cancer as a differential diagnosis in young patients with altered bowel habits, or in patients with fatigue in the absence of specific bowel symptoms. Further prospective research is needed to further define bowel habits in this cohort.

Lower peripouch fat area is related with increased frequency of pouch prolapse and floppy pouch complex in inflammatory bowel disease patients

BACKGROUND

Pouch prolapse is a rare pouch complication which often leads to pouch failure in inflammatory bowel disease (IBD) patients. Its exact cause remains unknown. Floppy pouch complex (FPC) was defined as the presence of any one of the following pouch disorders: pouch prolapse, afferent limb syndrome (ALS), redundant loop, and pouch folding. We aimed to explore the role of peripouch fat area in the occurrence of pouch prolapse and FPC.

METHODS

Pouch patients with available pouchoscopy and abdominal CT scans who were followed up between 2011 and 2017 in Cleveland Clinic were reviewed. Peripouch fat was measured on CT images.

RESULTS

Of the 93 included patients, 31 were females; 87 had J pouches and 6 had S pouches. The median duration of pouch was 8.0 (interquartile range [IQR] 5.0-16.5) years. A total of 18 cases (19.4%, 18/93) were identified as FPC, including 12 pouch prolapse, 5 ALS, 1 redundant loop, and 3 pouch folding. Patients with pouch prolapse had lower peripouch fat area (13.6 (9.3-18.5) vs. 27.6 (11.0-46.2)cm², P = 0.022) than those without. Patients with FPC had lower peripouch fat area (15.4 (11.4-20.6) vs. 27.6 (11.0-46.9)cm², P = 0.040) than those without. Univariate and multivariate analyses demonstrated that lower peripouch fat area, lower weight, and family history of IBD were independent predictors of pouch prolapse and FPC.

CONCLUSIONS

A lower peripouch fat area was observed in inflammatory bowel disease patients with pouch prolapse and FPC. Longitudinal studies are needed to further elucidate the role of peripouch fat in the pathogenesis of pouch prolapse and FPC.

CoA Synthase (COASY) Mediates Radiation Resistance via PI3K Signaling in Rectal Cancer

Neoadjuvant radiation is standard of care for locally advanced rectal cancer. Response to radiation is highly variable and directly linked with survival. However, there currently are no validated biomarkers or molecular targets to predict or improve radiation response, which would help develop personalized treatment and ideally targeted therapies. Here, we identified a novel biomarker, coenzyme A synthase (COASY), whose mRNA expression was consistently elevated in radioresistant human rectal cancers. This observation was validated in independent patient cohorts and further confirmed in colorectal cancer cell lines. Importantly, genetic overexpression and knockdown yielded radioresistant and sensitive phenotypes, respectively, in vitro and in vivo. COASY-knockdown xenografts were more vulnerable to radiation, showing delayed tumor growth, decreased proliferation, and increased apoptosis. Mechanistically, COASY protein directly interacted with the PI3K regulatory subunit PI3K-P85α, which increased AKT and mTOR phosphorylation, enhancing cell survival. Furthermore, shRNA COASY knockdown disrupted downstream PI3K pathway activation and also hindered DNA double-strand break repair, which both led to improved radiosensitivity. Collectively, this work reveals for the first time the biological relevance of COASY as a predictive rectal cancer biomarker for radiation response and offers mechanistic evidence to support COASY as a potential therapeutic target. SIGNIFICANCE: COASY is a novel radiotherapy response modulator in rectal cancer that regulates PI3K activation and DNA repair. Furthermore, COASY levels directly correlate with radiation response and serve as a predictive biomarker.

Difference in the frequency of pouchitis between ulcerative colitis and familial adenomatous polyposis: is the explanation in peripouch fat?

AIM

Patients with ulcerative colitis (UC) have an unexplained higher incidence of pouchitis and a greater amount of peripouch fat compared with patients with familial adenomatous polyposis (FAP). The aims of this study were to compare the peripouch fat areas between patients with UC and patients with FAP, and to explore relationship between peripouch fat and pouchitis or chronic antibiotic-refractory pouchitis (CARP).

METHOD

Patients with an abdominal CT image from our prospectively maintained Pouch Database were included. Abdominal fat and peripouch fat were measured on CT images at different levels or planes. Comparisons of peripouch fat and CARP were performed before and after propensity score matching.

RESULTS

A total of 277 patients with UC and 40 patients with FAP were included. Compared with patients with FAP, patients with UC were found to have a higher incidence of pouchitis (58.5% vs 15.0%, P < 0.001) and CARP (24.5% vs 2.5%, P = 0.002) and a higher total peripouch fat area (P = 0.030) and mesenteric peripouch fat area (P = 0.022) at Level-3. Univariate and multivariate analyses showed that diagnosis (UC vs FAP) and peripouch fat areas at Level-3 and Level-5 were independent risk factors for CARP. With propensity score matching, 38 pairs of patients with UC and FAP were matched successfully. After matching, patients with UC were found to have higher total peripouch fat area and higher mesenteric peripouch fat area at Level-3, and a higher incidence of pouchitis (57.9% vs 13.2%, P < 0.001) and CARP (23.7% vs 2.6%, P = 0.007).

CONCLUSION

Our study demonstrates that patients with UC have more peripouch fat than those with FAP, which may explain the difference in the frequency of pouchitis and CARP between these groups of patients.

Prognostic significance of BRAF mutation alone and in combination with microsatellite instability in stage III colon cancer

PURPOSE

The prognostic significance of biomarkers in colorectal cancer is still being defined. This study aimed to determine the prognostic significance of BRAF mutation alone and in combination with microsatellite instability (MSI), in stage III colon cancer.

METHODS

Curatively resected stage III colon cancers were studied from a 33-year period. Clinicopathological data were collated (adjuvant chemotherapy, age, gender, obstruction, perforation, tumour location, grade, presence of mucin, nodal stage, extramural vascular, and perineural invasion). MSI status was established and molecular testing for BRAF (V600E) was performed. Four mutation categories were examined: "traditional" (microsatellite stable [MSS]/BRAF -ve), "presumed Lynch" (MSI/BRAF -ve), "sporadic MSI" (MSI/BRAF +ve), and "other BRAF" (MSS/BRAF +ve). These factors were correlated with cancer-specific survival.

RESULTS

In total, 686 unselected cases met our inclusion criteria, of which 15.7% had a BRAF mutation and 13.8% showed MSI. In the adjusted analysis, neither BRAF mutation nor MSI mutation were independently prognostic. On univariate analysis, survival in presumed Lynch cancers was similar to traditional cancers (5-year survival: 62% and 61%, respectively). While there was no difference in cancer-specific survival between sporadic MSI and other BRAF, both these tumour group had poorer outcome when compared to traditional or presumed Lynch cancers. Adjusted analysis of the four groups, however, showed that none of the subgroups were independently prognostic.

CONCLUSION

BRAF-mutated cancers demonstrated a trend toward poorer outcomes, however, when adjusted for clinicopathological factors and chemotherapy, BRAF mutation was not found to be an independent prognostic biomarker in stage III colon cancer, even when combined with MSI.

The interaction between BRAF mutation and microsatellite instability (MSI) status in determining survival outcomes after adjuvant 5FU based chemotherapy in stage III colon cancer

PURPOSE

The predictive role of biomarkers in colon cancer is still being defined. The aim of this study is to determine the interaction between BRAF mutation and microsatellite instability (MSI) status in determining survival benefit after adjuvant 5-FU based chemotherapy in stage III colon cancer.

METHODS

We performed a retrospective cohort study including all curatively resected stage III colon cancer cases over a 33-year period. A clinicopathological database was collated (adjuvant chemotherapy, age, gender, obstruction, perforation, tumor location, grade, mucin, nodal stage, extramural vascular, and perineural invasion). BRAF (V600E) mutation testing was performed and MSI status established by immunohistochemistry for mismatch repair proteins and molecular testing for National Cancer Institute panel markers. Patients were categorized into four groups for comparison: MSS and BRAF-ve (termed " traditional"), MSI and BRAF-ve (termed " presumed Lynch"), MSI and BRAF+ve (termed " sporadic MSI"), and MSS and BRAF+ve (termed " other BRAF"). The primary endpoint was cancer specific survival. Interaction testing was conducted to determine whether there were different responses to chemotherapy between groups.

RESULTS

A total of 686 unselected cases met inclusion criteria and had tissue available, of which 15.7% had BRAF mutation (BRAF+ve) and 13.8% had MSI. Thirty-nine percent received chemotherapy. Overall, adjuvant chemotherapy produced a cancer specific survival benefit (HR 0.66, 95% CI, 0.49-0.88, P < 0.01). On adjusted analysis, neither BRAF nor MSI status were individually predictive of survival benefit. On adjusted analysis specifically of the chemotherapy effect in each subgroup, only patients in the presumed Lynch (HR 0.260, 95% CI, 0.09-0.80, P < 0.01) and other BRAF groups (HR 0.45, 95% CI, 0.23-0.87, P < 0.01) had a significant survival benefit from chemotherapy. On interaction testing of subgroups, adjusting for all the clinicopathological parameters, only patients in the presumed Lynch group (HR 0.277, 95% CI, 0.10-0.75, P < 0.01) gained a differentially greater benefit from chemotherapy than other groups.

CONCLUSIONS

In this historical cohort, MSI testing is predictive of response to adjuvant chemotherapy in stage III colon cancer, but only when results are interpreted in combination with BRAF. This supports the role of routine testing for these biomarkers.

Peripouch Fat Area Measured on MRI Image and Its Association With Adverse Pouch Outcomes

BACKGROUND

There are no published studies on the impact of peripouch fat on pouch outcomes in inflammatory bowel disease (IBD) patients.

METHODS

Patients with pelvic MRI-DIXON scans from our prospectively maintained Pouch Database between 2002 and 2016 were evaluated. Peripouch fat area was measured on MRI-DIXON-F images at the middle height level of the pouch (area M) and the highest level of the pouch (area H).

RESULTS

Of all 1863 patients in the database, 197 eligible patients were included in this study. The median of area M was 52.4 cm2, so the 197 patients were classified into 2 groups: group 1 (Area-M <52.4 cm2) and group 2 (Area-M ≥52.4 cm2). Compared with group 1, group 2 was found to have thicker perianal fat, more Caucasian and more males. Group 2 also had a higher Area-H, more weight, height, and body mass index, along with greater age at IBD diagnosis, age at pouch construction and pouch age, and a higher frequency of total pouch complication (86.7% versus 66.7%, P = 0.001), chronic pouch complication (68.4% versus 51.5%, P = 0.016), and chronic antibiotic-refractory pouchitis (16.3% versus 7.1%, P = 0.043). Multivariate logistic analysis showed that Area-M was an independent risk factor for chronic antibiotic-refractory pouchitis (odds ratio [OR]: 1.025; 95% confidence interval [CI]: 1.007-1.042, P = 0.005). The 22 patients with 2 or more pelvic MRI-DIXON scans were further classified into 2 groups by the change from the initial to latest MRI-DIXON scans. Patients with Area-M increase ≥10% and Area-M/height increase ≥10% were found to have shorter pouch survivals than those with increase <10%.

CONCLUSIONS

A new method was established for measuring peripouch fat using pelvic MRI-DIXON-F image. Our study suggests that accumulation of peripouch fat may be associated with poor outcomes in selected IBD patients suspected of inflammatory or mechanical disorders of the pouch. Whether this association is causal warrants further investigation.

Pelvic MRI and CT images are interchangeable for measuring peripouch fat

A total of 27 pouch patients with inflammatory bowel diseases, who underwent pelvic MRI-DIXON and CT scan within one year, were included. Peripouch fat areas were measured at the middle height level of pouch (AreaM) and the highest level of pouch (AreaH). Our results demonstrated that measurements of perianal fat thickness, AreaM and AreaH based on MRI image were accurate and reproducible (correlation efficiency(r): intraobserver: 0.984–0.991; interobserver: 0.969–0.971; all P < 0.001). Bland-Altman analysis showed that more than 92.593% (25/27) of dots fell within the limits of agreement. We also identified strong agreements between CT and MRI image in measuring perianal fat thickness(r = 0.823, P < 0.001), AreaM (r = 0.773, P < 0.001) and AreaH (r = 0.862, P < 0.001). Interchangeable calculating formula to normalize measurements between CT and MRI images were created: Thickness_CT = 0.610 × Thickness_MRI + 0.853; AreaM_CT = 0.865 × AreaM_MRI + 1.392; AreaH_CT = 0.508 × AreaH_MRI + 15.001. In conclusion, pelvic MRI image is a feasible and reproducible method for quantifying peripouch fat. Pelvic MRI and CT images are interchangeable in retrospective measurements of peripouch fat, which will foster future investigation of the role of mesentery fat in colorectal diseases.

Colorectal stenting for malignant obstruction: an 8-year clinical experience

BACKGROUND

  A substantial percentage of patients with colorectal cancer present with obstructive symptoms. In such patients, surgery is often required and is associated with significant morbidity and mortality. Colorectal stenting is an increasingly commonplace alternative with potentially fewer risks than open surgery. We present our clinical experience over an 8-year period with colorectal stenting in a major tertiary Australian hospital.

METHODS

  From 2000 to 2008, patients undergoing colorectal stenting were identified via medical records. Clinical data collected included patient demographics, tumour type, extent of metastatic disease, stent characteristics, technical and clinical success, acute and chronic complications, and long-term follow-up status.

RESULTS

  Thirty-five patients (69 ± 13 years, 25 male) received a total of 39 stents. Technical success was achieved in 37 (95%), and clinical relief of obstruction was achieved in 34 (89%). One case was complicated by perforation at the time of procedure and three cases experienced delayed perforation. Reintervention was required in 17% of patients, all of whom had less than 50% hepatic volume replacement by metastatic disease.

CONCLUSIONS

  Colorectal stenting is a feasible and safe alternative for patients presenting with obstructive symptoms but the benefit may be restricted to patients with a short expected survival.