Table 5.
Objectives and conclusions of studies.
| Author, publication date and country | Objectives | Conclusions |
|---|---|---|
| Chen B (2019), China | “To investigate whether the dCCA has a certain correlation with biliary microecology, and to detect specific strains”. | Microbiota of patients with dCCA differed significantly from those with lithiasis alone. Individuality in the biliary microbiota was found, per patient. Such information can be used to treat diseases of the biliary tract. |
| Vogtmann E (2020), USA | “We evaluated the association between oral microbiota and pancreatic cancer in Iran”. | The oral microbiota differed between cases and controls, with some bacterial rates being more abundant or present in the cases, and this may be related to the presence of cancer, or risk for development. |
| Half E (2019), Israel | “To examine the gut microbiome alterations in PC and their potential to serve as biomarkers”. | Given the difficulty of associating microbial patterns with cancer, this would become even more difficult in its early stages. An alternative would be to compare the microbial pattern with other non-invasive biomarkers. |
| Serra N (2018), Canada | “In this study, we aimed to assess the bile microbiological flora and its potential link with comorbidity in women”. | More analyses are needed to better understand the virulence of known pathogens and there may be an association between non-adherence to the Mediterranean diet and changes in the intestinal microbiota and bacteria. |
| Olson SH (2017), USA | “In this pilot study, we compared the oral microbiota in patients with newly diagnosed, untreated, PDAC, and healthy controls, hypothesizing that the oral microbiota would differ between cases and controls”. | There does not appear to be a strong relationship between the risk of PDAC and IPMN and oral microbiota, but differences in individual “rates” should be evaluated in larger studies, which also need to work on confounding variables of association between cases and controls. |
| Di Carlo P (2019), Italy | “To evaluate the effect of bile microbiota on survival in patients with Pancreas and Biliary Tract Disease (PBD)”. | Some bacteria isolated from bile samples can be considered risk factors for carcinogenesis and/or progression of diseases of the biliopancreatic tract, and this knowledge is important for the indication of antimicrobial therapies for these patients with PBD neoplasms. |
| Mei Q-X (2018), China | “In this study, our aim was to characterize the specific composition of the duodenal microbiota in pancreatic cancer patients using 16S ribosomal RNA (rRNA) pyrosequencing methods”. | The role of the duodenal microbiota in pancreatic head cancer cannot be ruled out, as the analysis of the microbiota based on LEfSe revealed small changes in relation to healthy control subjects. |
| Erick R (2019), USA | “To gain insights on the host-related influences that might guide this unusual long-term survival”. | The tumor microbiome has a powerful effect in determining PDAC survival. The unique LTS tumor microbiome may contribute to form a favorable tumor microenvironment, characterized by the recruitment and activation of CD8 T cells into the tumor milieu and may also be useful as a predictor of patient outcomes. The microbiome-based prognostic tool, results represent an opportunity to manipulate the microbiome to improve the life expectancy of patients with PDAC. |
| Torres PJ (2015), USA | “To determine the salivary profiles of patients with and without pancreatic cancer. The use of HTS to sequence 16S rRNA bacterial genes from entire salivary microbial communities allows for a more comprehensive profile of the microbiome in health and disease”. | There was a higher proportion of Leptotrichia in patients with pancreatic cancer, while the proportion of Porphyromonas and Neisseria was lower in these patients. More studies on the subject with a larger number of patients are needed to overcome biases. |
| Ren Z (2017), China | “Thus, it is hypothesized that gut microbiota is associated with PC but gut microbial characteristics in clinical PC have not been reported... The gut microbial composition, taxonomic difference, microbial function prediction and microbial markers were performed”. | Patients with CP showed reduced gut microbiota diversity and a unique microbial profile that differs from CH, partially attributed to decreased alpha diversity. Intestinal microbial changes in PC showed an increase in some potential pathogens and LPS-producing bacteria and a decrease in some probiotics and butyrate-producing bacteria. Changes in microbial gene functions were consistent with taxonomic changes in PC. Streptococcus has been associated with bile in the intestine. |
| Fan X (2018), USA | “Determine if oral microbiome was associated with subsequent risk of pancreatic cancer”. | The study demonstrates that transport of P. gingivalis and A. actinomycetemcomitans and decreased relative abundance of the phylum Fusobacteria and its genus Leptotrichia are related to an increased subsequent risk of pancreatic cancer. It also provides evidence that oral microbiota may play a role in the etiology of pancreatic cancer. |
| Kohi S (2021), EUA | “We tested the hypothesis that duodenal fluid may contain microbial alterations associated with PDAC”. | There are changes in the duodenal fluid microbiome and mycobiota in patients with PDAC that could be used to better stratify pancreatic cancer risk |
| Saab M (2021), France | “To investigate (...) a series of 30 extrahepatic CCA patients who underwent ERCP in an effort to identify the biliary microbiota signature”. | Given the significant differences between microbiota of patients with and without cancer, excluding comorbidities that could act as a possible confounding factor, CCA dysbiosis can help to identify patients with this cancer. |
| Sun H (2020), China | “We carried out this research to discover new available salivary biomarkers of PC, and to comprehensively explain the potential mechanism of oral microbes in the pathogenesis of PC”. | There is a difference between the oral microbiota of healthy people and those with pancreatic diseases (such as pancreatic cancer), but more study is needed to determine the causal relationship between the two situations. |
| Wei AL (2020), China | “To investigate the saliva microbiome distribution in patients with pancreatic adenocarcinoma (PDAC) and the role of oral microbiota profiles in detection and risk prediction of pancreatic cancer”. | The composition of the oral microbiome is different in PDAC and healthy individuals and this knowledge of the bacterial flora is important for developing treatments and reducing the risk of pancreatic cancer. |
CCA, Cholangiocarcinoma; PC, Pancreatic Cancer; IPMN, Intraductal Papillary Mucinous Neoplasms; PBD, Pancreas and Biliary Tract Disease; PDAC, Pancreatic Ductal Adenocarcinoma; LTS, Long Term Survival; HTS, High-Throughput Sequencing; ERCP, Endoscopic Retrograde Cholangiopancreatography.