Estimation of the incidence of urachal cancer: A systematic review and meta-analysis of registry-based studies.

BACKGROUND: Urachal cancer (UrC) is a rare disease with limited availability of representative incidence and clinical data. Although, the prevalence is accounting for less than 1% of bladder tumors, the 5-year survival rate is around only 50% for patients with resectable tumors, and even worse for patients with metastatic disease. Due to the lack of comprehensive prospective studies, our current knowledge of UrC is still limited. OBJECTIVE: The present study aimed to summarize the available registry-based studies with unselected UrC patients to evaluate its incidence and clinicopathological characteristics. MATERIAL AND METHODS: We conducted a systematic literature search of registry-based UrC publications on the 15th of May 2023 in 5 databases, which identified 4,748 publications. After duplicate removal and selection by 2 independent investigators, 6 publications proved to be appropriate for the final meta-analysis. Estimated incidence and clinicopathological parameters were extracted. RESULTS: Estimated incidence ranged between 0.022 and 0.060/ 100.000 person-years, with the highest occurrence in Japan and the lowest in Canada, while the random effect model calculated an overall incidence rate of 0.04 (95%CI: 0.03-0.05) 100.000 person-years. The median age at first diagnosis was 60 years (range: 58-64). The female to male ratio was 2:3. Lymph node or distant metastases were present in 9% and 14% of patients. The predominant tumour type was adenocarcinoma (86%) followed by urothelial carcinoma (12%) and squamous cell carcinoma (2%). The 5-year survival rate was 51.0% with 95%CI: 45.2-57.4. CONCLUSIONS: Our study provides an up-to-date comparison of estimated incidence rates between 6 countries of 3 continents based on rigorously selected registry-based studies. The results suggest low incidence rates for UrC with considerable geographic differences. The present meta-analysis provides unbiased registry-based data on the incidence, clinicopathological parameters and survival of UrC.

Probiotic supplementation during antibiotic treatment is unjustified in maintaining the gut microbiome diversity: a systematic review and meta-analysis.

BACKGROUND: Probiotics are often used to prevent antibiotic-induced low-diversity dysbiosis, however their effect is not yet sufficiently summarized in this regard. We aimed to investigate the effects of concurrent probiotic supplementation on gut microbiome composition during antibiotic therapy. METHODS: We performed a systematic review and meta-analysis of randomized controlled trials reporting the differences in gut microbiome diversity between patients on antibiotic therapy with and without concomitant probiotic supplementation. The systematic search was performed in three databases (MEDLINE (via PubMed), Embase, and Cochrane Central Register of Controlled Trials (CENTRAL)) without filters on 15 October 2021. A random-effects model was used to estimate pooled mean differences (MD) with 95% confidence intervals (CI). This review was registered on PROSPERO (CRD42021282983). RESULTS: Of 11,769 identified articles, 15 were eligible in the systematic review and 5 in the meta-analyses. Quantitative data synthesis for Shannon (MD = 0.23, 95% CI: [(-)0.06-0.51]), Chao1 (MD = 11.59 [(-)18.42-41.60]) and observed OTUs (operational taxonomic unit) (MD = 17.15 [(-)9.43-43.73]) diversity indices revealed no significant difference between probiotic supplemented and control groups. Lacking data prevented meta-analyzing other diversity indices; however, most of the included studies reported no difference in the other reported α- and ß-diversity indices between the groups. Changes in the taxonomic composition varied across the eligible studies but tended to be similar in both groups. However, they showed a potential tendency to restore baseline levels in both groups after 3-8 weeks. This is the first meta-analysis and the most comprehensive review of the topic to date using high quality methods. The limited number of studies and low sample sizes are the main limitations of our study. Moreover, there was high variability across the studies regarding the indication of antibiotic therapy and the type, dose, and duration of antimicrobials and probiotics. CONCLUSIONS: Our results showed that probiotic supplementation during antibiotic therapy was not found to be influential on gut microbiome diversity indices. Defining appropriate microbiome diversity indices, their standard ranges, and their clinical relevance would be crucial.