Introduction

Colorectal carcinoma (CRC) is one of the most important indications for colorectal surgery despite the availability of screening measures. Anastomotic leakage is among the most common potentially life-threatening complications. Increasing evidence suggests a causal role of the gut microbiota in the pathogenesis of anastomotic leakage.

Aims & Methods

The aim of the study was to evaluate the dynamics of microbiome changes in patients with colorectal carcinoma before, during and after surgical intervention in relation to anastomotic insufficiency. From a total of 18 patients recruited, the records of 16 patients were systematically analysed according to inclusion/exclusion criteria and sequencing quality. Biopsies were taken from the 3 sites (proximal to the tumour, tumour region, distal to the tumour) before, during and after surgery. All patients received preoperative Metronidazole and Paromomycin for intraluminal bowel decontamination and a single intravenous dose of Ertapenem during surgery. DNA extraction was followed by amplification of the V1-V2 region of the 16S rRNA gene and Illumina sequencing.

Results

Phocaeicola, Prevotella and Enterococcus were the most abundant of the 259 different genera found in the cohort. Hierarchical clustering showed that samples from the same patient at the same time point generally had high similarity (66%), and in 6 cases all samples from more than one time point formed a cluster. These results were corroborated by comparing the Bray-Curtis similarity of sample sites and time points. Periinterventional procedures were associated with a significant decrease in diversity in samples collected during or after surgery. Samples with anastomotic leakage had a different microbial structure at all time points, with Prevotella being more abundant in the anastomotic leakage group (p<0.0001), whereas Phocaeicola was more abundant in the sufficient anastomosis group (p=0.04). Systematic longitudinal analysis revealed an increasing abundance of bacterial species, particularly Enterococcus and Escherichia/Shigella, at subsequent sampling times.

Conclusion

The mucosal microbiota is substantially altered by colorectal surgery, and the microbiome of patients with anastomotic leakage differs from that of patients with sufficient anastomoses. Further studies are needed to unravel the molecular and functional interactions between the microbiota and mucosal tissue.

Introduction

Sessile Serrated Lesions (SSLs) show an “ultra flat” morphology, a mucus cap and are predominantly located proximally to the splenic flexure (PSF) (1). Hypothetically, previous knowledge in detection of flat or non-protruding conventional adenoma could be a predictor factor for endoscopic detection of SSLs.

Aims & Methods

Aim: To investigate in a South American Private Hospital, the relationship between Flat Adenomas Detection Rate (FADR) and Sessile Serrate Lesion Detection Rate (SDR)
Methods: This study is a retrospective, single-center analysis carried out at Centro Medico Docente La Trinidad Caracas-Venezuela from total selected colonoscopies performed by the gastroenterologists between 2008 and 2018 in patients 51-80 years old (YO). For this study, Adenoma Detection Rate (ADR) includes the whole morphologic spectrum of colon & rectum traditional adenomas from Paris Classification of Colorectal Lesions (2). We will consider the “General ADR” as “GADR”, including Non-protruding or flat ADR: “FADR” plus Protruding ADR: “PADR”, as well as the last two separately. By using logistic regression generalized estimating equation models, the location in colon & rectum and morphology of all types of adenomas (ADs) were assessed. The relationship between the global number of colonoscopies (GNC), GADR, FADR, PADR and the SDR was investigated calculating a correlation coefficient (CC) weighted by the number of total colonoscopies. In addition, 3 linear regression equation models to estimate the relationship between the 3 different types of ADR and SDR and the probability of occurrence of SDR based on the proportion of colonoscopies with SDR presenting every type of ADR weighted by the number of colonoscopies with SDR were calculated.

Results

Results of the linear regression models used to estimate the relationship between the different types of ADR and SDR and the probability of occurrence based on the number of Centro Medico Docente La Trinidad colonoscopies
Category of ADR	R2	β	P	SDR Correlation coefficient	Probability of occurrence (%)	Colonoscopies in each category of ADR validated for SDR calculation
General ADR	0.9687	0.1632	<0.001	0.9842	94.26	148
Flat ADR	0.759	1.888	0.002	0.8712	92.35	145
Protruding ADR	0.3186	0.1664	0.113	0.5644	37.58	59
R2 : Determination coefficient. This evaluates the strength of the linear relationship between the two variables.
β: Partial regression coefficient. It indicates the average effect that the increase in one unit of the predictor variable has on the dependent variable.
ADR: Adenoma Detection Rate. SDR: Serrated Detection Rate. 157 colonoscopies were valid for the calculation of the SDR

For this study, 8432 colonoscopies were validated for 9 gastroenterologists (G1-G9). For patients between 51 and 80 YO, GADR for all 9 Gastroenterologists was 19.76%. GADR-SDR individually for 9 gastroenterologists (G1-G9) varies from as high as G9 GADR-SDR: 33.21%-4.19% to as low as G1: 12.67%-0.50%. The most frequent location for ADs was PSF: OR 1.95, IC 95% (1.30-2.84), P<0.001. SSLs were mostly located PSF OR 2.18, IC 95% (1.44, 2.92) P<0.001. The morphology of ADs was mainly pedicle OR 1.00 IC 95% P<0.001 and for SSL it was flat by far: OR 6.84 IC 95% (2.08-9.02) P<0.001. The CC demonstrated a good association between GADR and SDR: 0.98 P<0.05; and for FADR: 0.87, P<0.05 but not for PADR: 0.56 P=0.113. The GNC was not associated with the SDR CC: -0.197, P=0.6117. The GADR and FADR show robust strength of the linear relationship with SDR and probability of occurrence, but not for PADR (table)

Conclusion

A sine qua non factor for a good SDR for the gastroenterologist is previous knowledge about “FADR”. To the best of our knowledge, this is the first time that ADR has been divided into “General, Flat and Protruded” in order to investigate the impact of the endoscopic skills on flat colorectal lesions detection for a good SDR.

References

1. Rex DK, Ahnen DJ, Baron JA et al. Serrated lesions of the colorectum: review and recommendations from an expert panel. Am J Gastroenterol 2012; 107: 1315-1329; quiz 1314, 1330 [PMID: 22710576 DOI: 10.1038/ ajg.2012.161]
2. Lambert R et al. Superficial Neoplastic Lesions in the Digestive Tract. Endoscopy 2005; 37: 570±578

Introduction

Over the world, fecal occult blood testing (FOBT) is used as a colorectal cancer (CRC) screening method for middle age and older age, but there are problems such as sensitivity/specificity issues, low participation rates in primary and secondary screenings, and that the incidence/mortality rates of CRC are still high. Fusobacterium nucleatum (Fn) has been reported to be frequently detected in the feces of CRC patients in recent years, and it has been reported that screening sensitivity can be increased by combining it with Fn PCR testing. However, due to the cost and technical complexity of PCR, it has not yet been widely used in clinical practice. In this study, we developed a simple method using ELISA to measure antibodies against FadA expressed by Fn and evaluated its usefulness.

Aims & Methods

We evaluated FOBT, Fn PCR quantification, and Fn (ELISA) in 41 individuals diagnosed with CRC from April 2020 to December 2022 and 41 healthy volunteers without CRC. Subgroup analysis was also performed in CRC patients at each stage.

Results

The correlation coefficient between Fn PCR quantification and Fn (ELISA) was good at r=0.722, p<0.001. FOBT alone had a sensitivity of 61% and a specificity of 100%. In Fn ELISA, when cut off#1 was set to maximize the AUC in ROC, the sensitivity and specificity were 76% and 78%, respectively, and when combined with FOBT, the sensitivity was 90% and the specificity was 78%. In screening, high specificity is required, so we set cut off#2 Fn ELISA to achieve a specificity of 93% and performed analysis. When combined with FOBT, the sensitivity was 73% and the specificity was 93%. When targeting advanced cancer of stage II or higher, the sensitivity by combining FOBT and Fn ELISA was 100% at cut off#1 and 79% at cut off#2, while for early cancer, the sensitivity was 76% at cut off#1 and 59% at cut off#2, both of which were better than the sensitivity of FOBT alone.

Conclusion

By combining Fn measurement using ELISA with FOBT, it was possible to increase the diagnostic sensitivity and reduce false negatives compared to FOBT alone. There are challenges such as setting appropriate cut-off values for use in screening, but measuring Fn in addition to FOBT may improve screening accuracy and increase the participation rate in secondary screening, and in the future, we would like to evaluate its effectiveness even in populations with low prior probability of screening participation.

Introduction

Cold snare polypectomy (CSP) for polyps 10-14 mm is unsatisfactory, with higher rates of unclear/positive histologic margins compared to small polyps,¹ which is similar for CSP with submucosal injection.² Therefore, hot snare polypectomy (HSP) or endoscopic mucosal resection (EMR) has been widely performed for polyps measuring ≥10 mm.³ However, these procedures often cause adverse events such as delayed bleeding and perforation due to deep thermal injury related to the use of electrocautery.⁴ A recent large-scale study reported a low incidence (0.9%) of invasive cancer in 10-19 mm colorectal polyps.⁵ Therefore, the development of less invasive therapeutic options for this size category is demanding.
Thus, we have developed HSP with low power pure-cut current (LPPC-HSP), a polypectomy technique with low power, low voltage, and no coagulation current (UMIN Clinical Trials Registry; UMIN000037678). This method uses pure-cut current and reduces the power of electrocautery, expecting less deep thermal damage compared with conventional HSP with blend or coagulation current, resulting in a lower risk of perforation and bleeding. This study aimed to evaluate the efficacy and safety of LPPC-HSP for colorectal polyps 10 to 14 mm, compared with conventional EMR.

Aims & Methods

In this multicenter, retrospective, observational study, records of patients who underwent EMR or LPPC-HSP for nonpedunculated colorectal polyps 10 to 14 mm at two Japanese institutions between January 2021 and March 2022 were evaluated consecutively. EMR was performed with blend cut current (Endocut Q; effect 3, time interval 2, time duration 2), while LPPC-HSP with a low power pure-cut current (Autocut; effect 1, 10 W in VIO300D or Autocut; effect 0.4 [Pmax 13 W] in VIO3). We analyzed the treatment outcomes of the two techniques using propensity score matching to reduce selection bias. The following variables expected to affect treatment outcomes were selected: age, sex, polyp size, morphology, lesion location, endoscopists (experienced endoscopists or gastrointestinal fellows), and antithrombotic agents. R0 resection was defined as en bloc resection with histologically tumor-free margins.

Results

We retrospectively enrolled 203 EMR (168 patients, 203 lesions) and 208 LPPC-HSP (169 patients, 208 lesions) cases. After propensity score matching, the baseline characteristics between the groups were comparable, with 131 pairs. The en bloc and R0 resection rates were not significantly different between EMR and LPPC-HSP groups (93.9% vs. 96.9%, P=0.38; 90.8% vs. 91.6%, P=1.00). The vertical margin was negative in all lesions except one in the EMR group. Immediate bleeding requiring hemostasis was observed in 10.7% of cases in the EMR group versus 2.3% in the LPPC-HSP group (P=0.010). The rates of delayed bleeding and perforation didn’t differ between the groups (0% vs. 0.8%, P=1.00; 0% vs. 0%).

Table 1. Baseline characteristics and treatment outcomes after propensity score matching
Baseline characteristics	EMR n=131	LPPC-HSP n=131	P value	standardized difference		Treatment outcomes	EMR n=131	LPPC-HSP n=131	P value
Age, years (interquartile range)	72 (67-76)	72 (68-78)	0.29	0.105		En bloc resection (%)	123 (93.9)	127 (96.9)	0.38
Male sex (%)	91 (70)	96 (73)	0.59	0.085		R0 resection (%)	119 (90.8)	120 (91.6)	1.00
Lesion size, mm (interquartile range)	10 (10-12)	10 (10-12)	0.93	0.017		Immediate bleeding (%)	14 (10.7)	3 (2.3)	0.01
Location right colon/left colon/rectum (%)	61 (47) / 53 (41) / 17 (13)	63 (48) / 53 (41) / 15 (12)	0.95	0.049		Delayed bleeding (%)	0 (0)	1 (0.8)	1.00
Morphology 0-Is/0-IIa (%)	89 (68) / 42 (32)	87 (66) / 44 (34)	0.90	0.033		Perforation (%)	0 (0)	0 (0)	N/A
Antithrombotic agents (%)	24 (18)	35 (27)	0.14	0.202
Gastrointestinal fellows performed (%)	42 (32)	44 (34)	0.90	0.033

Conclusion

LPPC-HSP showed treatment outcomes comparable to conventional EMR, with fewer adverse events. These results suggest that this technique is a safe and effective treatment for nonpedunculated colorectal polyps 10 to 14 mm.

References

1. Hirose R, Yoshida N, Murakami T, et al. Histopathological analysis of cold snare polypectomy and its indication for colorectal polyps 10-14 mm in diameter. Dig Endosc 2017;29:594-601.
2. Yabuuchi Y, Imai K, Hotta K, et al. Efficacy and safety of cold-snare endoscopic mucosal resection for colorectal adenomas 10 to 14 mm in size: a prospective observational study. Gastrointest Endosc 2020;92:1239-1246.
3. Ferlitsch M, Moss A, Hassan C, et al. Colorectal polypectomy and endoscopic mucosal resection (EMR): European Society of Gastrointestinal Endoscopy (ESGE) Clinical Guideline. Endoscopy 2017;49:270-297.
4. Oka S, Tanaka S, Kanao H, et al. Current status in the occurrence of postoperative bleeding, perforation and residual/local recurrence during colonoscopic treatment in Japan. Dig Endosc 2010;22:376-380.
5. Parsa N, Ponugoti P, Broadley H, et al. Risk of cancer in 10 - 19 mm endoscopically detected colorectal lesions. Endoscopy 2019;51:452-457.

Disclosure

Authors declare no Conflict of Interests for this study.