The Prospect of Harnessing the Microbiome to Improve Immunotherapeutic Response in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma cancer (PDAC) is projected to become the second leading cause of cancer-related death in the United States by 2030. Patients are often diagnosed with advanced disease, which explains the dismal 5-year median overall survival rate of ~12%. Immunotherapy has been successful in improving outcomes in the past decade for a variety of malignancies, including gastrointestinal cancers. However, PDAC is historically an immunologically "cold" tumor, one with an immunosuppressive environment and with restricted entry of immune cells that have limited the success of immunotherapy in these tumors. The microbiome, the intricate community of microorganisms present on and within humans, has been shown to contribute to many cancers, including PDAC. Recently, its role in tumor immunology and response to immunotherapy has generated much interest. Herein, the current state of the interaction of the microbiome and immunotherapy in PDAC is discussed with a focus on needed areas of study in order to harness the immune system to combat pancreatic cancer.

A phase II study of neoadjuvant liposomal irinotecan with 5-FU and oxaliplatin (NALIRIFOX) in pancreatic adenocarcinoma.

For patients with localized pancreatic cancer with minimal vascular involvement, optimal survivability requires a multidisciplinary approach of surgical resection and systemic chemotherapy. FOLFIRINOX is a combination chemotherapy regimen that offers promising results in the perioperative and metastatic settings; however, it can cause significant adverse effects. Such toxicity can negatively impact some patients, resulting in chemotherapy discontinuation or surgical unsuitability. In an effort to reduce toxicities and optimize outcomes, this investigation explores the safety and feasibility of substituting liposomal irinotecan (nal-IRI) for nonliposomal irinotecan to improve tumor drug delivery and potentially reduce toxicity. This regimen, NALIRIFOX, has the potential to be both safer and more effective when administered in the preoperative setting.

For patients with pancreatic cancer with little to no cancer near the blood vessels, the best life expectancy usually requires surgery and chemotherapy. FOLFIRINOX is a chemotherapy medicine that offers promising results for both patients getting surgery and for patients with widespread disease. However, it can cause harmful side effects. The side effects can be so bad that the chemotherapy has to be stopped or that surgery is no longer possible. In order to reduce the harmful side effects and improve outcomes, this investigation looks into the safety and practicality of using a different version of one of the medicines. The different version hopes to improve drug delivery and reduce harmful side effects. This regimen, NALIRIFOX, can be safer and more effective in patients awaiting surgery. Clinical Trial Registration: UF-STO-PANC-004 (NCT03483038) (ClinicalTrials.gov).

Role of Bacteria in the Development of Colorectal Cancer.

Colorectal cancer (CRC) is the second leading cause of cancer-related death in the United States. Once limited to older populations, the incidence of CRC in patients under the age of 50 years is increasing and the etiology for this is uncertain. One hypothesis lies on the impact of the intestinal microbiome. The intestinal microbiome, composed primarily of bacteria but also viruses, fungi, and archaea, has been shown to regulate CRC development and progression both in vitro and in vivo. In this review, the role and intersection of the bacterial microbiome in various stages of clinical CRC development and management are discussed beginning with CRC screening. Various mechanisms whereby the microbiome has been shown to modulate CRC development including the influence of diet on the microbiome, bacterial-induced injury to the colonic epithelium, bacterial-produced toxins, and alteration of normal cancer immunosurveillance by the microbiome are discussed. Finally, the influence of microbiome on the response of CRC to treatment is discussed while highlighting ongoing clinical trials. The complexities of the microbiome and its role in CRC development and progression have become apparent and will require ongoing commitment to translate laboratory findings into meaningful clinical results that will aid more than 150,000 patients that develop CRC every year.

The Influence of the microbiome on the innate immune microenvironment of solid tumors.

Cancer remains a leading cause of death despite many advances in medical and surgical therapy. In recent decades, the investigation for novel therapeutic strategies with greater efficacy and reduced side effects has led to a deeper understanding of the relationship between the microbiome and the immune system in the context of cancer. The ability of the immune system to detect and kill cancer is now recognized to be greatly influenced by the microbial ecosystem of the host. While most of these studies, as well as currently used immunotherapeutics, focus on the adaptive immune system, this minimizes the impact of the innate immune system in cancer surveillance and its regulation by the host microbiome. In this review, known influences of the microbiome on the innate immune cells in the tumor microenvironment will be discussed in the context of individual innate immune cells. Current and needed areas of investigation will highlight the field and its potential impact in the clinical treatment of solid malignancies.

Association of Medical Appointment Cancellation Rates on Survival After Esophagectomy for Esophageal Cancer.

BACKGROUND: Cancelled healthcare appointments, especially in patients with complex cancers, such as esophageal cancer, risk delayed treatment and adverse outcomes. We hypothesized that patients with greater rates of healthcare appointment cancellations would have decreased survival after esophagectomy for esophageal cancer. METHODS: A retrospective analysis of patients from a single institution who underwent esophagectomy for esophageal cancer between 2004 and 2020 was performed. Appointment cancellations were queried 2 years pre-/post-esophagectomy and categorized as medical or ancillary. Continuous and categorical variables were compared by Mann-Whitney and chi-squared analyses, respectively. Survival associations post-esophagectomy were made by Kaplan-Meier analysis. RESULT: Seventy-six patients were identified. Total medical and ancillary appointments post-esophagectomy increased by 188% and 136%, respectively. Per patient, there was a median increase of 57.5 medical appointments in the post-esophagectomy period. Of medical appointments, 23.7% were cancelled pre-esophagectomy but 33.4% post-esophagectomy (p < 0.001). This trend held true for ancillary appointments. Patients with increased medical cancellation rates post-esophagectomy had shortened recurrence-free (p = 0.09) and overall survival (p < 0.01) versus patients with low cancellation rates. CONCLUSION: A significant increase in healthcare appointments is seen after esophagectomy. Patients with increased healthcare appointment cancellations have decreased post-esophagectomy survival which presents an opportunity to intervene in patients who historically have a high cancellation rate.

Atezolizumab plus tivozanib for immunologically cold tumor types: the IMMCO-1 trial.

Immune checkpoint inhibitor therapy represents a significant advance in cancer care. The interaction between PD-1 and PD-L1 induces immune tolerance and the inhibition of this interaction is an effective treatment strategy for numerous malignancies. Despite its demonstrated potential, immunotherapy is not clinically effective in immunogenically 'cold' tumors such as pancreatic cancer, prostate cancer and neuroendocrine tumors. Through the inhibition of VEGF, it may be possible to potentiate the effect of immune checkpoint blockade in tumors that have traditionally shown a lack of clinical response to immunotherapy. This signal-seeking, single-arm, prospective clinical trial aims to determine the objective response of tivozanib and atezolizumab in advanced immunogenically cold solid tumors. Clinical Trial Registration: NCT05000294 (ClinicalTrials.gov).

Intestinal microbiota modulates pancreatic carcinogenesis through intratumoral natural killer cells.

Preclinical data demonstrate that the gut microbiota can promote pancreatic ductal adenocarcinoma (PDAC), but mechanisms remain unclear. We hypothesized that intestinal microbiota alters anti-tumor innate immunity response to facilitate PDAC progression. Human PDAC L3.6pl cells were heterotopically implanted into Rag1-/- mice after microbiota depletion with antibiotics, while syngeneic murine PDAC Pan02 cells were implanted intrapancreatic into germ-free (GF) C57BL/6 J mice. Natural killer (NK) cells and their IFNγ expression were quantitated by flow cytometry. NK cells were depleted in vivo using anti-Asialo GM1 antibody to confirm the role of NK cells. Bacteria-free supernatant from SPF and GF mice feces was used to test its effect on NK-92MI cell anti-tumor response in vitro. SPF and ex-GF mice (reconstituted with SPF microbiota) developed larger PDAC tumors with decreased NK cell tumor infiltration and IFNγ expression versus GF-Rag1-/-. Microbiota-induced PDAC tumorigenesis was attenuated by antibiotic exposure, a process reversed following NK cell depletion in both Rag1-/- and C57BL/6 J mice. Compared to GF, SPF-Rag1-/- abiotic stool culture supernatant inhibited NK-92MI cytotoxicity, migration, and anti-cancer related gene expression. Gut microbiota promotes PDAC tumor progression through modulation of the intratumoral infiltration and activity of NK cells.

Sex differences associate with late microbiome alterations after murine surgical sepsis.

BACKGROUND: Sepsis-induced gut microbiome alterations contribute to sepsis-related morbidity and mortality. Given evidence for improved postsepsis outcomes in females compared with males, we hypothesized that female mice maintain microbiota resilience versus males. METHODS: Mixed-sex C57BL/6 mice underwent cecal ligation and puncture (CLP) with antibiotics, saline resuscitation, and daily chronic stress and were compared with naive (nonsepsis/no antibiotics) controls. For this work, the results of young (3-5 months) and old (18-22 months) adult mice were analyzed by sex, independent and dependent of age. Mice were sacrificed at days 7 and 14, and 16S rRNA gene sequencing was performed on fecal bacterial DNA. α and ß diversity were determined by Shannon index and Bray-Curtis with principal coordinate analysis, respectively. False discovery rate (FDR) correction was implemented to account for potential housing effect. RESULTS: In control mice, there was no difference in α or ß diversity between male and female mice (FDR, 0.76 and 0.99, respectively). However, male mice that underwent CLP with daily chronic stress had a decrease in microbiota α diversity at 7 days post-CLP (Shannon FDR, 0.005), which was sustained at 14 days post-CLP (Shannon FDR, 0.001), compared with baseline. In addition, male mice maintained differences in ß diversity even at day 14 compared with controls (FDR, <0.0001). In contrast, female mice had a decreased microbiota α diversity (Shannon FDR, 0.03) and ß diversity (FDR, 0.02) 7 days post-CLP but recovered their α and ß diversity by post-CLP day 14 (Shannon FDR, 0.5, and FDR, 0.02, respectively). Further analysis of females revealed that only young female mice were not different (ß diversity) post-CLP day 14 to controls. CONCLUSION: Although sepsis-induced perturbations of the intestinal microbiota occur initially in both male and female C57BL/6 mice, females demonstrate different microbiota by day 14. This may be seen primarily in younger females. This difference in recovery may play a role in outcome differences between sexes after sepsis.

When is a lipoma not a lipoma? Case report presenting a lipoblastoma-like tumor of the gluteal cleft in an older gentleman with literature review.

INTRODUCTION AND IMPORTANCE: Lipoblastoma-like tumors are rare tumors that can be confused with lipoblastomas and liposarcomas but have distinct characteristics. This tumor has previously been identified in the vulva of females, and recently in isolated cases of young males. Given its rarity, we present an instance of this tumor in an older man, demonstrating that this pathology is not limited to a specific age or sex, and surgeons and pathologists must be aware of it in their differential. CASE PRESENTATION: A 58-year-old male presented for evaluation of an enlarging mass in his right gluteal cleft. Prior to referral for surgical evaluation, the patient underwent an ultrasound-guided biopsy of the mass. Histologically, the tumor was a low-grade cellular spindle cell neoplasm in a fibrous to myxoid stroma. Immunohistochemical and molecular workup ruled out several malignant mesenchymal neoplasms, including myxoid liposarcoma, dedifferentiated liposarcoma, melanoma, low-grade fibromyxoid sarcoma, and sarcomatoid carcinoma. The patient initially declined surgery, but the mass continued to grow, and excision was chosen given the uncertain pathology. The tumor was resected with negative margins and histologically characterized as a "lipoblastoma-like lesion", with features of a myxoid liposarcoma and spindle cell lipoma. Seven months post-resection, there were no signs of recurrence or metastasis. CLINICAL DISCUSSION: Despite radiologic and pathologic similarities to malignant lipomatous tumors, lipoblastoma-like tumors are benign and have a good prognosis. CONCLUSIONS: Clinicians should be aware of this entity despite its rarity as resection with negative margins is curative and may be needed to rule out more aggressive tumors.

Routine Radiologic Assessment for Anastomotic Leak Is Not Necessary in Asymptomatic Patients After Esophagectomy for Esophageal Cancer.

BACKGROUND: Anastomotic leaks (AL) are a major source of post-esophagectomy morbidity and patients are often initially asymptomatic. Debate exists on timing and utility of imaging to detect AL post-esophagectomy. We sought to evaluate the efficacy and timing of radiographic AL evaluation in esophageal cancer patients post-esophagectomy. METHODS: A retrospective database of esophageal cancer patients who underwent esophagectomy at a single institution from 2004 to 2020 was used to determine the utilization, timing, and sensitivity of radiologic testing for AL post-esophagectomy. RESULTS: Seventy-six patients were identified of which 37 (49%) had a cervical anastomosis. Sixty-four (84%) underwent 71 "asymptomatic radiographic leak tests" (ARLT), 7 of which had 2 different tests, including: 41 fluoroscopic esophagrams (58%), 18 CT-esophagrams (25%), and 12 upper GI studies (17%). Seventeen patients (22%) developed clinical signs of AL (hemodynamic instability, leukocytosis) and underwent "symptomatic radiographic leak tests" (SRLT) with fluoroscopic esophagram (n = 9, 12%), CT-esophagram (n = 7, 9%), or upper GI study (n = 1, 1%). ARLT and SRLT were positive in 2/64 (3%) and 17/17 (100%) patients, respectively, for 19 total ALs (25%). Among the 17 SRLT( +) patients, 1 was also ARLT( +), 13 were initially ARLT( -), and 3 were not evaluated by ARLT. The median postoperative day for ARLT and SRLT was 4.0 (IQR 3.0-5.5) and 9.0 days (IQR 6.0-13.0), respectively, with a statistically significant difference (p < 0.005). The sensitivity and specificity of ARLT for detecting AL were 13.3% and 100.0%, respectively. CONCLUSIONS: Based on the low ARLT sensitivity, routine use of imaging to detect asymptomatic ALs post-esophagectomy may be limited. Symptomatic ALs were often present in a delayed fashion, even after initial negative imaging.

Stress-related changes in the gut microbiome after trauma.

BACKGROUND: The gut microbiome protects the host from infection by promoting epithelial integrity and providing basal immunologic stimulation. Disruption of this delicate ecosystem is linked to morbidity and mortality among critically ill patients, but the impact of traumatic injury on the gut microbiome is poorly understood. This study sought to identify alterations in gut microbiota following trauma and persistent stress in rodents without confounding antibiotics. METHODS: Male Sprague-Dawley rats aged 9 weeks to 11 weeks were randomized to naive, lung contusion with hemorrhagic shock (LCHS), and LCHS plus either 7 (LCHS/CS 7/7) or 14 days (LCHS/CS 14) of restraint cylinder stress for 2 hours daily. Stool was collected on Days 0, 3, 7, and 14 for bacterial whole genome DNA isolation. Alpha diversity, or the number and relative abundance of unique bacterial species within each cohort, was assessed using Chao1 indices. Beta diversity, or the measure of differences in biodiversity across cohorts, was assessed by principle coordinate analysis. False discovery rate correction was applied to all statistical analyses and corrected for cohousing effects. RESULTS: Rodent groups subject to restraint stress demonstrated a progressive increase in alpha diversity over time. These microbiota changes resolved after cessation of stress (LCHS/CS 7/7) but continued to increase among rats subjected to ongoing stress (LCHS/CS 14). The LCHS/CS 7/7 also demonstrated reductions in class Actinobacteria and increased abundance of the genus Bacteroides by Day 7, which resolved by Day 14. Increased abundance of Bacteroides was also noted in the LCHS/CS 14 cohort, suggesting the role of chronic stress in its destabilization. CONCLUSION: This study points to persistent stress as a potential source of the destabilization of microbial diversity seen after trauma. This lack of microbiota stability could be associated with worse long-term outcomes in critically ill trauma patients. Further studies are warranted to elucidate mechanistic pathways and potential therapeutic modalities.

Implications of the microbiome in the development and treatment of pancreatic cancer: Thinking outside of the box by looking inside the gut.

Pancreatic ductal adenocarcinoma is the third leading cause of cancer-related death in the United States. As one of the most lethal cancer types, the prognosis for patients diagnosed with pancreatic cancer remains dismal and novel investigations are urgently needed. Evidence for an association of microbes with pancreatic cancer risk, development, treatment response, and post-treatment survivorship is rapidly developing. Herein, we provide an overview on the role of the microbiome as it relates to the natural history of pancreatic cancer, including host immune interactions, alterations in metabolism, direct carcinogenic effect, and its role in treatment response.

SSAT State-of-the-Art Conference: Advancements in the Microbiome.

The microbiome plays a major role in human physiology by influencing obesity, inducing inflammation, and impacting cancer therapies. During the 60th Annual Meeting of the Society of the Alimentary Tract (SSAT) at the State-of-the-Art Conference, experts in the field discussed the influence of the microbiome. This paper is a summary of the influence of the microbiome on obesity, inflammatory bowel disease, pancreatic cancer, cancer therapies, and gastrointestinal optimization. This review shows how the microbiome plays an important role in the development of diseases and surgical complications. Future studies are needed in targeting the gut microbiome to develop individualized therapies.

Proton Pump Inhibitor Use After Hiatal Hernia Repair: Inhibitor of Recurrent Symptoms and Potential Revisional Surgery.

BACKGROUND: Hiatal hernia recurrence after hiatal hernia repair (HHR) is often underdiagnosed and underreported but may present with recurrent gastroesophageal reflux disease (GERD) symptoms. Because of their availability, proton pump inhibitor (PPI) use is common and may mask patients who would benefit from revisional surgery, which has been shown to improve symptoms and quality of life. METHODS: A retrospective analysis was performed to evaluate recurrence patterns of patients who underwent HHR, specifically for the indication of GERD, from 2007 to 2015 at a single Veterans Administration Medical Center. Clinicopathologic parameters were reviewed for association with hiatal hernia recurrence, including postoperative PPI use. RESULTS: Sixty-four patients were identified with a median follow-up time of 57.8 mo. Thirty-eight patients developed an anatomic recurrence, which did not demonstrate any associated factors on univariate analysis. Seventy percent of patients remained or were restarted on PPI after their initial surgery. For patients with a documented recurrence, the median time to start a PPI was 224 d, but the time to identify recurrence on imaging or endoscopy was 712.5 d. Eleven (39.3%) patients had a reintervention for anatomic recurrence, of which all had developed recurrent symptoms of GERD. CONCLUSIONS: Most patients who developed recurrent hiatal hernia were restarted on PPI without workup for their symptoms. The time of initiation of PPI was much earlier than the time of identification of a recurrent hiatal hernia. The use of PPIs in patients whom have undergone HHR may delay proper workup to identify recurrent hiatal hernia amenable to surgical repair and should be reserved until patients develop recurrent symptoms and have at least begun a diagnostic workup to rule out an anatomic cause for the recurrent symptoms.

Minimally Invasive Ivor Lewis Esophagectomy with Linear Stapled Anastomosis Associated with Low Leak and Stricture Rates.

BACKGROUND: Minimally invasive foregut surgery is increasingly performed for both benign and malignant diseases. We present a retrospective series of patients who underwent minimally invasive Ivor Lewis esophagectomy (MIE) with linear stapled anastomosis performed at two centers in the USA, with a focus on evaluating leak and stricture rates. METHODS: Patients treated from 2007 to 2018 were included, and data on demographics, oncologic treatment, pathology, and outcomes were analyzed. The surgical technique utilized laparoscopic and thoracoscopic access, with an intrathoracic esophagogastric anastomosis using a 6-cm linear stapled side-to-side technique. RESULTS: A total of 124 patients were included and 114 resections (91.9%) were completed in a minimally invasive fashion with a 6-cm linear stapled side-to-side anastomosis. Patients were predominantly male (90.7%) with a median age of 66.0 years and body mass index of 28.8 kg/m2. Of 121 patients with malignancy, negative margins were obtained in 94.3% and median lymph node yield was 15 (IQR 12-22). In the intention to treat analysis, median operative time was 463 min (IQR 403-515), blood loss was 150 mL (IQR 100-200), and length of stay was 8 days (IQR 7-11). Postoperative complications were experienced by 64 patients (51.6%) including respiratory failure in 14 (11.3%) and pneumonia in 12 (9.7%). In patients who successfully underwent a 6-cm stapled side-to-side anastomosis, anastomotic leaks occurred in 6 patients (5.1%) without need for operative intervention, and anastomotic strictures occurred in 6 patients (5.1%) requiring endoscopic management. CONCLUSIONS: Ivor Lewis MIE with a 6-cm linear stapled anastomosis can be completed with a high technical success rate, and low rates of anastomotic leak and stricture.

Protein Signatures and Tissue Diagnosis of Pancreatic Cancer.

BACKGROUND: Endoscopic ultrasound-guided fine-needle aspiration fails to diagnose up to 25% of patients with pancreatic ductal adenocarcinoma (PDAC). Proteomics can help to overcome this clinical dilemma. We hypothesized that soluble protein signatures can differentiate PDAC from benign tissues. STUDY DESIGN: Tissues were obtained from resected surgical specimens, lysed, and homogenates collected for analysis with a 41-protein multiplex assay. Analyte concentrations were normalized to total protein. Statistical analysis was performed to evaluate for differences in PDAC vs benign tissue. RESULTS: Tissues were obtained from 159 patients, 82 patients with PDAC naïve to therapy and 77 with benign pancreatic pathology. Fourteen analytes had a receiver operating characteristic curve area of >0.75 for predicting PDAC vs benign tissue. A recursive partitioning model using only 2 analytes, interleukin 1 receptor antagonist and transforming growth factor-α, provided an accuracy, sensitivity, and specificity of 91.2%, 90.2%, and 92.2%, respectively. A penalized logistic regression model found 12 analytes that provide diagnostic value to a protein signature. The mean area under the receiver operating characteristic after 50 tenfold cross-validations was 0.951. Accuracy, sensitivity, and specificity of this model were 91.2%, 87.8%, and 94.8%, respectively. Applying the scenario of 80% disease prevalence in patients undergoing endoscopic ultrasound with fine-needle aspiration for a pancreatic head mass, positive predictive value is 98.5% (95% CI 93.0% to 99.7%) and negative predictive value is 66.0% (95% CI 54.9% to 75.6%). CONCLUSIONS: Protein signatures from pancreatic specimens can differentiate PDAC from benign tissue. Additional work to validate these findings in a unique sample set is warranted.

Microbiota in pancreatic health and disease: the next frontier in microbiome research.

Diseases intrinsic to the pancreas such as pancreatitis, pancreatic cancer and type 1 diabetes mellitus impart substantial health and financial burdens on society but identification of novel mechanisms contributing to these pathologies are slow to emerge. A novel area of research suggests that pancreatic-specific disorders might be modulated by the gut microbiota, either through a local (direct pancreatic influence) or in a remote (nonpancreatic) fashion. In this Perspectives, we examine literature implicating microorganisms in diseases of the pancreas, specifically pancreatitis, type 1 diabetes mellitus and pancreatic ductal adenocarcinoma. We also discuss evidence of an inherent pancreatic microbiota and the influence of the intestinal microbiota as it relates to disease association and development. In doing so, we address pitfalls in the current literature and areas of investigation that are needed to advance a developing field of research that has clinical potential to reduce the societal burden of pancreatic diseases.