Introduction

Endoscopic submucosal dissection (ESD) is an effective treatment for superficial esophageal cancer, but postoperative stenosis remains a significant concern. Particularly, probability of the stenosis is less investigated in cases with a 50%-75% circumferential mucosal defect.

Aims & Methods

This study aimed to identify influential factors for postoperative stenosis after the moderate circumferential resection in esophageal ESD. This multi-center retrospective observational study analyzed data from 513 patients across 19 institutions who underwent esophageal ESD from April 2018 to March 2022 and showed 50% to 75% of the circumferential mucosal defect. We firstly overviewed the current status on the postoperative stenosis, the steroid use, and postoperative adverse events in these patients. Subsequently, we identified influential factors for postoperative stenosis. Patients were categorized into stenosis and no stenosis groups, and univariate and multivariate analyses were performed for each parameter. We further investigated influential factors of stenosis in two cohorts: steroid and no steroid groups. Finally, the parameters were compared between the steroid and no steroid groups to assess the tendency of the steroid use in general practice.

Results

Postoperative stenosis was observed in 28 cases (5%). Univariate analysis comparing the stenosis group (n = 28) and no stenosis group (n = 485) revealed significant differences in the prior endoscopic treatment near the lesion (p = 0.02), cervical esophageal location (p = 0.04), defect circumference (p =0.01), and procedure duration (p = 0.02). There was no significant difference in the steroid use between two groups. Multivariate analyses identified history of prior endoscopic treatment close to the lesion (p = 0.01, odds ratio [OR], 5.10), cervical esophageal lesions (p = 0.03, OR, 3.97), large circumferential defect (p <0.01, OR, 3.78), and longer procedure duration (p <0.01, OR, 3.83) as independent risk factors for stenosis formation. Among the steroid group, significant associations of the postoperative stenosis were revealed with the prior endoscopic treatment near the lesion (p = 0.02), cervical esophageal location (p = 0.04), and >5/8 of defect circumference (p = 0.02). In the no steroid group, only the procedure duration (p = 0.01) showed a significant difference between the stenosis and non-stenosis groups. Comparison between the steroid (n = 223) and no steroid groups (n = 290) revealed significant differences in the prior endoscopic treatment near the lesion (p <0.01), cervical esophageal lesions (p <0.01), and resected specimen dimensions (p <0.01). The stenosis rates were 7% in the steroid group and 4% in the no steroid group, without a significant difference. No significant difference in adverse events was observed between the two groups.

Conclusion

In esophageal ESD with a 50%-75% circumferential mucosal defect, the steroid was used in over 40% of patients, and postoperative stenosis still occurred in 5%. Because wider circumference, location of the cervical esophagus, prior endoscopic treatment close to the lesion, and prolonged operative time were identified as independent risk factors on the stenosis, steroid therapy should be preferred in these cases. Particularly, lesions with a history of endoscopic treatment, on cervical esophagus, and with >5/8 of defect circumference should require more aggressive countermeasures than currently applied.

Introduction

The pathophysiological mechanism involved in irritable bowel syndrome (IBS) is thought to be multifactorial, involving the gut-brain axis and the immune system. Despite this complexity, dietary restriction of fermentable oligo-, dis-, mono- saccharides, and polyols (FODMAPs) has become the first line of treatment, improving symptoms in up to 80% of patients (1). FODMAPs are poorly absorbed in the small intestine and serve as a substrate for the colonic microbiota, which has been proposed as a key mediator of FODMAP tolerance and symptom development. Considering that both the gut microbiota and the (in)tolerance to individual FODMAPs are highly personalised (2), there is a growing need to understand the host-microbiota interactions underlying individual responses to FODMAP restriction and intake. This personalised interplay may be key to more targeted dietary interventions for IBS.

Aims & Methods

We aimed to disentangle the role of the gut microbiota in FODMAP tolerance by exploring microbial dynamics upon restriction and reintroducing individual FODMAPs. To this end, we performed 16S rRNA gene sequencing of over 1,700 faecal samples from 463 IBS patients participating in two clinical trials: a) The DOMINO trial (3), where primary-care patients underwent a FODMAP-lowering diet and b) A cohort of 117 tertiary-care patients underwent a strict FODMAP-restriction followed by a blinded re-introduction of 6 FODMAPs powders (2). Response to the diet was defined as a reduction of at least 50 points on the IBS symptom severity scale. Linear and logistic mixed models were used to assess the relation between the microbiome, response to dietary intervention, host genetics and 32 blood and faecal parameters.

Results

Participants with dysbiotic microbiota at baseline were shown to be less likely to respond to the dietary restriction (p-value=0.01). These participants also showed higher levels of fecal calprotectin, secretory IgA and eosinophil-derived neurotoxin, suggesting immune activation in this subgroup of IBS patients (p-value<0.05). In both cohorts, limiting FODMAP intake was associated with decreased Bifidobacterium abundance (FDR<0.01). Moreover, a dose-dependent effect was observed as depletion was less severe in the FODMAP-lowering DOMINO diet. This effect was independent of response and IBS subtype. Furthermore, total bacterial biomass did not change during the restriction or the reintroduction period. However, we found 25 significant associations between individual FODMAPs and gut bacteria. The reintroduction of galacto-oligosaccharides and fructans restored the levels of Bifidobacterium, while polyols increased the abundance of Anaerostipes, regardless of participants’ tolerance (FDR<0.05). In addition, we observed distinct dynamics in the gut microbiota associated with the tolerance of specific FODMAPs, although they did not reach significance after multiple testing corrections at the current sample size. For example, participants intolerant to sorbitol showed an increase in Alistipes upon exposure to this compound (p-value<0.05, FDR>0.05).

Conclusion

Our results suggest that microbiota composition at baseline influences the clinical response to FODMAP restriction. A low-FODMAP diet does not induce drastic changes in the microbiome composition, although we confirmed the negative impact of dietary restriction on the abundance of Bifidobacterium. However, the less restrictive DOMINO diet results in a milder depletion, suggesting that moderate FODMAP reduction may better preserve beneficial microbiota while still offering symptom relief. Finally, we found evidence for a link between microbial dynamics and FODMAP tolerance, although this needs to be confirmed in larger cohorts.

References

(1) Staudacher HM, Whelan K The low FODMAP diet: recent advances in understanding its mechanisms and efficacy in IBS Gut 2017;66:1517-1527.
(2) Van den Houte K, Colomier E, Routhiaux K, Mariën Z, Schol J, Van den Bergh J, Vanderstappen J, Pauwels N, Joos A, Arts J, Caenepeel P, De Clerck F, Matthys C, Meulemans A, Jones M, Vanuytsel T, Carbone F, Tack J. Efficacy and Findings of a Blinded Randomized Reintroduction Phase for the Low FODMAP Diet in Irritable Bowel Syndrome. Gastroenterology. 2024
(3) Carbone F, Van den Houte K, Besard L DOMINO Study Collaborators, et al Diet or medication in primary care patients with IBS: the DOMINO study - a randomised trial supported by the Belgian Health Care Knowledge Centre (KCE Trials Programme) and the Rome Foundation Research Institute Gut 2022;71:2226-2232.

Disclosure

JT has given Scientific advice to AlfaWassermann, Allergan, Christian Hansen, Danone, Grünenthal, Ironwood, Janssen, Kiowa Kirin, Menarini, Mylan, Neutec, Novartis, Noventure, Nutricia, Shionogi, Shire, Takeda, Theravance, Tramedico, Truvion, Tsumura, Zealand and Zeria pharmaceuticals, has received research support from Shire, Sofar and Tsumura, and has served on the Speaker bureau for Abbott, Allergan, AstraZeneca, Janssen, Kyowa Kirin, Menarini, Mylan, Novartis, Shire, Takeda, Truvion and Zeria. Funding was provided by a Methusalem grant from Leuven University to JT This study was supported by a research grant from the Belgian Health Care Knowledge Centre (KCE).