Pancreatic duct occlusion with polychloroprene-based glue for the management of postoperative pancreatic fistula after pancreatoduodenectomy-an outdated approach?

Background

Managing postoperative pancreatic fistula (POPF) presents a formidable challenge after pancreatoduodenectomy. Some centers consider pancreatic duct occlusion (PDO) in reoperations following pancreatoduodenectomy as a pancreas-preserving procedure, aiming to control a severe POPF. The aim of the current study was to evaluate the short- and long-term outcomes of employing PDO for the management of the pancreatic stump during relaparotomy for POPF subsequent to pancreatoduodenectomy.

Methods

Retrospective review of consecutive patients at Oslo University Hospital undergoing pancreatoduodenectomy and PDO during relaparotomy. Pancreatic stump management during relaparotomy consisted of occlusion of the main pancreatic duct with polychloroprene Faxan-Latex, after resecting the dehiscent jejunal loop previously constituting the pancreaticojejunostomy.

Results

Between July 2005 and September 2015, 826 pancreatoduodenectomies were performed. Overall reoperation rate was 13.2% (n = 109). POPF grade B/C developed in 113 (13.7%) patients. PDO during relaparotomy was performed in 17 (2.1%) patients, whereas completion pancreatectomy was performed in 22 (2.7%) patients. Thirteen (76%) of the 17 patients had a persistent POPF after PDO, and the time from PDO until removal of the last abdominal drain was median 35 days. Of the PDO patients, 13 (76%) patients required further drainage procedures (n = 12) or an additional reoperation (n = 1). In-hospital mortality occurred in one patient (5.9%). Five (29%) patients developed new-onset diabetes mellitus, and 16 (94%) patients acquired exocrine pancreatic insufficiency.

Conclusions

PDO is a safe and feasible approach for managing severe POPF during reoperation following pancreatoduodenectomy. A significant proportion of patients experience persistent POPF post-procedure, necessitating supplementary drainage interventions. The findings suggest that it is advisable to explore alternative pancreas-preserving methods before opting for PDO in the management of POPF subsequent to pancreatoduodenectomy.

Intraductal papillary neoplasms of the bile ducts: a comparative study of a rare disease in Europe and Nagoya, Japan

BACKGROUND

Intraductal papillary neoplasm of the bile ducts (IPNB) is a rare disease in Western countries. The aim of this study was to compare tumor characteristics, management strategies, and outcomes between Western and Eastern patients who underwent surgical resection for IPNB.

METHODS

A multi-institutional retrospective series of patients with IPNB undergoing surgery between January 2010 and December 2020 was gathered under the auspices of the European-African Hepato-Pancreato-Biliary Association (E-AHPBA), and at Nagoya University Hospital, Japan.

RESULTS

A total of 85 patients (51% male; median age 66 years) from 28 E-AHPBA centers were compared to 91 patients (64% male; median age 71 years) from Nagoya. Patients in Europe had more multiple lesions (23% vs 2%, P < .001), less invasive carcinoma (42% vs 85%, P < .001), and more intrahepatic tumors (52% vs 24%, P < .001) than in Nagoya. Patients in Europe experienced less 90-day grade >3 Clavien-Dindo complications (33% vs 68%, P < .001), but higher 90-day mortality rate (7.0% vs 0%, P = .03). R0 resections (81% vs 82%) were similar. Overall survival, excluding 90-day postoperative deaths, was similar in both regions.

DISCUSSION

Despite performing more extensive resections, the low perioperative mortality rate observed in Nagoya was probably influenced by a combination of patient-, tumor-, and surgery-related factors.

The prognostic effect of tumor-associated macrophages in stage I-III colorectal cancer depends on T cell infiltration

BACKGROUND

Tumor-associated macrophages (TAMs) are associated with unfavorable patient prognosis in many cancer types. However, TAMs are a heterogeneous cell population and subsets have been shown to activate tumor-infiltrating T cells and confer a good patient prognosis. Data on the prognostic value of TAMs in colorectal cancer are conflicting. We investigated the prognostic effect of TAMs in relation to tumor-infiltrating T cells in colorectal cancers.

METHODS

The TAM markers CD68 and CD163 were analyzed by multiplex fluorescence immunohistochemistry and digital image analysis on tissue microarrays of 1720 primary colorectal cancers. TAM density in the tumor stroma was scored in relation to T cell density (stromal CD3+ and epithelial CD8+ cells) and analyzed in Cox proportional hazards models of 5-year relapse-free survival. Multivariable survival models included clinicopathological factors, MSI status and BRAFV600E mutation status.

RESULTS

High TAM density was associated with a favorable 5-year relapse-free survival in a multivariable model of patients with stage I-III tumors (p = 0.004, hazard ratio 0.94, 95% confidence interval 0.90-0.98). However, the prognostic effect was dependent on tumoral T-cell density. High TAM density was associated with a good prognosis in patients who also had high T-cell levels in their tumors, while high TAM density was associated with poorer prognosis in patients with low T-cell levels (pinteraction = 0.0006). This prognostic heterogeneity was found for microsatellite stable tumors separately.

CONCLUSIONS

This study supported a phenotypic heterogeneity of TAMs in colorectal cancer, and showed that combined tumor immunophenotyping of multiple immune cell types improved the prediction of patient prognosis.

Peri-firing compression in prevention of pancreatic fistula after distal pancreatectomy: A systematic review and a cohort study

BACKGROUND/AIMS

Clinically relevant postoperative pancreatic fistula (CR-POPF) after distal pancreatectomy (DP) occurs in 20%-40% of patients and remains a leading cause of morbidity and increased healthcare cost in this patient group. Recently, several studies suggested decreased risk of CR-POPF with the use of peri-firing compression (PFC) technique. The aim of this report was to conduct a systematic review to get an overview of the current knowledge on the use of PFC in DP. In addition, our experience with PFC was presented.

METHODS

The systematic literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Also, 19 patients undergoing DP with the use of PFC at Oslo University Hospital were studied. The primary endpoint was incidence of CR-POPF.

RESULTS

Seven articles reporting a total of 771 patients were ultimately included in the systematic review. Only two of these were case-control studies examining outcomes in patients with and without PFC, while the rest were case series. These were heterogeneous in terms of staplers used, cartridge selection policy, and PFC technique. Both case-control studies reported significantly reduced CR- POPF incidence with PFC. Eight (21%) of our patients developed CR-POPF after DP with PFC. Only one patient developed CR-POPF among those with pancreatic transection site thickness ⩽1.5 cm.

CONCLUSION

Evidence on potential benefits of PFC in DP is limited in quantity and quality. Our findings suggest that the use of PFC does not lead to reduction in the incidence of CR-POPF. Yet, there might be a benefit from PFC when dealing with a thin pancreas.

Cancer risk and survival according to body mass index in hepatobiliary malignancies: a nationwide registry-based cohort study

BACKGROUND

The aim of this study was to explore the associations between BMI and cancer of the liver, bile ducts, and gallbladder.

METHODS

A registry-based cohort study was performed by linking data from several national registries in Norway.

RESULTS

The cohort comprised 1 723 692 individuals including 4768 hepatobiliary cancer cases during 55 743 509 person-years of follow-up. In men, we found increased risk of cancer per 5 kg/m2 BMI increase for hepatocellular carcinoma and extrahepatic cholangiocarcinoma. In women there was increased risk of extrahepatic cholangiocarcinoma and gallbladder cancer. Women with high BMI in early adulthood had increased risk of intrahepatic cholangiocarcinoma. Reduced cancer-specific survival was found for all hepatobiliary malignancies in women with overweight and obesity. In men, reduced survival was observed in individuals with obesity for all hepatobiliary cancers, except gallbladder cancer. Increased risk of cancer-death per 5 kg/m2 BMI increase was found for hepatocellular carcinoma, intra-, and extrahepatic cholangiocarcinoma in women. For men, 5 kg/m2 BMI increase was positively associated with cancer-death from intrahepatic cholangiocarcinoma.

DISCUSSION

This study supports the notion of an increased risk of hepatobiliary cancers with increasing BMI, with sex and age variations. The findings also suggest a higher risk of cancer-death with increasing BMI.

Human small intestine contains 2 functionally distinct regulatory T-cell subsets

BACKGROUND

Regulatory T (Treg) CD4 cells in mouse gut are mainly specific for intestinal antigens and play an important role in the suppression of immune responses against harmless dietary antigens and members of the microbiota. However, information about the phenotype and function of Treg cells in the human gut is limited.

OBJECTIVE

We performed a detailed characterization of Foxp3+ CD4 Treg cells in human normal small intestine (SI) as well as from transplanted duodenum and celiac disease lesions.

METHODS

Treg cells and conventional CD4 T cells derived from SI were subjected to extensive immunophenotyping and their suppressive activity and ability to produce cytokines assessed.

RESULTS

SI Foxp3+ CD4 T cells were CD45RA-CD127-CTLA-4+ and suppressed proliferation of autologous T cells. Approximately 60% of Treg cells expressed the transcription factor Helios. When stimulated, Helios-negative Treg cells produced IL-17, IFN-γ, and IL-10, whereas Helios-positive Treg cells produced very low levels of these cytokines. By sampling mucosal tissue from transplanted human duodenum, we demonstrated that donor Helios-negative Treg cells persisted for at least 1 year after transplantation. In normal SI, Foxp3+ Treg cells constituted only 2% of all CD4 T cells, while in active celiac disease, both Helios-negative and Helios-positive subsets expanded 5- to 10-fold.

CONCLUSION

The SI contains 2 subsets of Treg cells with different phenotypes and functional capacities. Both subsets are scarce in healthy gut but increase dramatically in active celiac disease.

Laparoscopic lavage for Hinchey III perforated diverticulitis: factors for treatment failure in two randomized clinical trials

BACKGROUND

The Scandinavian Diverticulitis (SCANDIV) trial and the LOLA arm of the LADIES trial randomized patients with Hinchey III perforated diverticulitis to laparoscopic peritoneal lavage or sigmoid resection. The aim of this analysis was to identify risk factors for treatment failure in patients with Hinchey III perforated diverticulitis.

METHODS

This was a post hoc analysis of the SCANDIV trial and LOLA arm. Treatment failure was defined as morbidity requiring general anaesthesia (Clavien-Dindo grade IIIb or higher) within 90 days. Age, sex, BMI, ASA fitness grade, smoking status, previous episodes of diverticulitis, previous abdominal surgery, time to surgery, and surgical competence were all tested in univariable and multivariable logistic regression analyses using an interaction variable.

RESULTS

The pooled analysis included 222 patients randomized to laparoscopic lavage and primary resection (116 and 106 patients respectively). Univariable analysis found ASA grade to be associated with advanced morbidity in both groups, and the following factors in the laparoscopic lavage group: smoking, corticosteroid use, and BMI. Significant factors for laparoscopic lavage morbidity in multivariable analysis were smoking (OR 7.05, 95 per cent c.i. 2.07 to 23.98; P = 0.002) and corticosteroid use (OR 6.02, 1.54 to 23.51; P = 0.010).

CONCLUSION

Active smoking status and corticosteroid use were risk factors for laparoscopic lavage treatment failure (advanced morbidity) in patients with perforated diverticulitis.

Pancreatoduodenectomy after Roux-en-Y gastric bypass surgery: Single-center experience and literature review

BACKGROUND AND OBJECTIVE

Bariatric surgery with Roux-en-Y gastric bypass (RYGB) is widely used to treat morbid obesity and present diagnostic and therapeutic challenges in patients with pancreatic and periampullary tumors. The aim of this study was to describe diagnostic tools and challenges in performing pancreatoduodenectomy (PD) on patients with altered anatomy after RYGB.

METHODS

Patients undergoing PD after RYGB from April 2015 to June 2022 at a tertiary referral center were identified. Preoperative workup, operative techniques, and outcomes were reviewed. A literature search was performed to identify articles reporting PD in post-RYGB patients.

RESULTS

Of a total of 788 PDs, six patients had previous RYGB. The majority were women (n = 5), and median age was 59 years. The patients most commonly presented with pain (50%) and jaundice (50%) with a median of 5.5 years after RYGB. The gastric remnant was resected in all cases, and reconstruction of the pancreatobiliary drainage was achieved using the distal part of the pre-existing pancreatobiliary limb in all patients. Median follow-up was 60 months. The Clavien-Dindo grade ⩾3 complications occurred in two patients (33.3%), and 90 days mortality occurred in one patient (16.6%). The literature search revealed 9 articles reporting a total of 122 cases, specifically addressing PD after RYGB.

CONCLUSIONS

Reconstruction after PD in post-RYGB patients may be challenging. Resection of the gastric remnant and use of the pre-existing biliopancreatic limb may be a safe strategy, but surgeons should be prepared for other reconstruction options for creation of a new pancreatobiliary limb.

Staged or Simultaneous Surgery for Colon or Rectal Cancer with Synchronous Liver Metastases: Implications for Study Design and Clinical Endpoints

In patients presenting with colorectal cancer and synchronous liver metastases, the disease burden related to the liver metastasis is the driving cause of limited longevity and, eventually, risk of death. Surgical resection is the potentially curative treatment for colorectal cancer liver metastases. In the synchronous setting where both the liver metastases and the primary tumor are resectable with a relative low risk, the oncological surgeon and the patient may consider three potential treatment strategies. Firstly, a "staged" or a "simultaneous" surgical approach. Secondly, for a staged strategy, a 'conventional approach' will suggest removal of the primary tumor first (either colon or rectal cancer) and plan for liver surgery after recovery from the first operation. A "Liver first" strategy is prioritizing the liver resection before resection of the primary tumor. Planning a surgical trial investigating a two-organ oncological resection with highly variable extent and complexity of resection as well as the potential impact of perioperative chemo(radio)therapy makes it difficult to find the optimal primary endpoint. Here, we suggest running investigational trials with carefully chosen composite endpoints as well as embedded risk-stratification strategies to identify subgroups of patients who may benefit from simultaneous surgery.

Intraductal papillary neoplasms of the bile duct: a European retrospective multicenter observational study (EUR-IPNB study)

BACKGROUND/PURPOSE

Intraductal papillary neoplasm of the bile duct (IPNB) is a rare disease in Western countries. The main aim of this study was to characterize current surgical strategies and outcomes in the mainly European participating centers.

METHODS

A multi-institutional retrospective series of patients with a diagnosis of IPNB undergoing surgery between 1 January 2010 and 31 December 2020 was gathered under the auspices of the European-African Hepato-Pancreato-Biliary Association. The textbook outcome (TO) was defined as a non-prolonged length of hospital stay plus the absence of any Clavien-Dindo grade at least III complications, readmission, or mortality within 90 postoperative days.

RESULTS

A total of 28 centers contributed 85 patients who underwent surgery for IPNB. The median age was 66 years (55-72), 49.4% were women, and 87.1% were Caucasian. Open surgery was performed in 72 patients (84.7%) and laparoscopic in 13 (15.3%). TO was achieved in 54.1% of patients, reaching 63.8% after liver resection and 32.0% after pancreas resection. Median overall survival was 5.72 years, with 5-year overall survival of 63% (95% CI: 50-82). Overall survival was better in patients with Charlson comorbidity score 4 or less versus more than 4 ( P =0.016), intrahepatic versus extrahepatic tumor ( P =0.027), single versus multiple tumors ( P =0.007), those who underwent hepatic versus pancreatic resection ( P =0.017), or achieved versus failed TO ( P =0.029). Multivariable Cox regression analysis showed that not achieving TO (HR: 4.20; 95% CI: 1.11-15.94; P =0.03) was an independent prognostic factor of poor overall survival.

CONCLUSIONS

Patients undergoing liver resection for IPNB were more likely to achieve a TO outcome than those requiring a pancreatic resection. Comorbidity, tumor location, and tumor multiplicity influenced overall survival. TO was an independent prognostic factor of overall survival.

Risk and survival in colorectal cancer with increasing body mass index: A nationwide population-based cohort study

AIM

The aim was to explore potential associations between the body mass index (BMI) and the risk of colorectal cancer (CRC), including subsites of the colon, and cancer-specific death.

METHODS

A registry-based cohort study was conducted with baseline data gathered from the Norwegian Tuberculosis Screening Programme, collected between 1963 and 1975, and linked to follow-up data from the Cancer Registry of Norway and the Norwegian Cause of Death Registry. Cox regression models were used to explore associations between BMI and CRC risk and cancer-specific death.

RESULTS

Of 1 723 692 included individuals, 76 616 developed CRC during 55 370 707 person-years of follow-up. In men, a 5 kg/m² increase in BMI was associated with an increased risk of colon cancer, including both right and left subsites, and rectal cancer. Allowing for nonlinearities, we found a U-shaped association for the right colon and an inverse U-shape for the left colon and rectum cancer. In women, a 5 kg/m² increase in BMI in early adulthood was associated with increased risk of colon cancer, including both subsites. In women, an increased risk of CRC death with increasing BMI was found for colon cancer.

CONCLUSIONS

Men of all ages have an increased risk of CRC with increasing BMI, with the highest risk for right-sided colon cancer. An increased risk for colon cancer was also found in women with high BMI in early adulthood. Furthermore, women of all age groups appeared to have an increased risk of CRC death with higher BMI.

Body mass index and pancreatic adenocarcinoma: A nationwide registry-based cohort study

BACKGROUND AND OBJECTIVE

An association between body mass index (BMI) and pancreatic cancer is suggested in observational studies. However, further studies are required to substantiate available evidence. The aim of this study was to explore the association between BMI and pancreatic ductal adenocarcinoma (PDAC) risk, treatment, and mortality.

METHODS

A registry-based cohort study was performed by combining data from four registries in Norway. Baseline data were collected between 1963 and 1975 with follow-up data collected until 2018. Kaplan-Meier curves and multivariable Cox regressions were estimated. Chi-square tests were used to analyze differences between groups.

RESULTS

The study cohort consisted of 1,723,692 individuals. A total of 8973 PDAC cases were identified during 55,744,749 person-years of follow-up. A 5 kg/m² increase in BMI was associated with an increased risk of PDAC if high BMI at young age (16-29 years) (hazard ratio (HR): 1.21, 95% confidence interval (CI): 1.13-1.31), both for men (HR: 1.30, 95% CI: 1.15-1.46) and women (HR: 1.16, 95% CI: 1.05-1.28). In men, there was a 52% increase in risk of early-onset PDAC (<age 50) (HR: 1.52, 95% CI: 1.13-2.03) with 5 kg/m² increase in BMI. A total of 2645 individuals were diagnosed with stage 1-3 disease, of whom 1131 underwent curative surgery. In all, 49% of normal weight, 38% overweight, and 30% obese individuals with stage 1-3 PDAC underwent surgery with curative intent (p < 0.001). Cancer survival was lower in overweight and obese individuals for both sexes. Analysis adjusted for sex, age, and period of diagnosis confirmed increased risk of cancer death in obese individuals.

CONCLUSION

This study suggests that increased BMI in young adults may increase the risk of PDAC, and higher BMI in men is associated with an increased risk of early onset PDAC (<age 50). Overweight and obese individuals were less likely to undergo curative surgery and obese individuals had a higher risk of cancer-related death.

Laparoscopic parenchyma-sparing liver resection for large (≥ 50 mm) colorectal metastases

BACKGROUND

Traditionally, patients with large liver tumors (≥ 50 mm) have been considered for anatomic major hepatectomy. Laparoscopic resection of large liver lesions is technically challenging and often performed by surgeons with extensive experience. The current study aimed to evaluate the surgical and oncologic safety of laparoscopic parenchyma-sparing liver resection in patients with large colorectal metastases.

METHODS

Patients who primarily underwent laparoscopic parenchyma-sparing liver resection (less than 3 consecutive liver segments) for colorectal liver metastases between 1999 and 2019 at Oslo University Hospital were analyzed. In some recent cases, a computer-assisted surgical planning system was used to better visualize and understand the patients' liver anatomy, as well as a tool to further improve the resection strategy. The surgical and oncologic outcomes of patients with large (≥ 50 mm) and small (< 50 mm) tumors were compared. Multivariable Cox-regression analysis was performed to identify risk factors for survival.

RESULTS

In total 587 patients met the inclusion criteria (large tumor group, n = 59; and small tumor group, n = 528). Median tumor size was 60 mm (range, 50-110) in the large tumor group and 21 mm (3-48) in the small tumor group (p < 0.001). Patient age and CEA level were higher in the large tumor group (8.4 μg/L vs. 4.6 μg/L, p < 0.001). Operation time and conversion rate were similar, while median blood loss was higher in the large tumor group (500 ml vs. 200 ml, p < 0.001). Patients in the large tumor group had shorter 5 year overall survival (34% vs 49%, p = 0.027). However, in the multivariable Cox-regression analysis tumor size did not impact survival, unlike parameters such as age, ASA score, CEA level, extrahepatic disease at liver surgery, and positive lymph nodes in the primary tumor.

CONCLUSION

Laparoscopic parenchyma-sparing resections for large colorectal liver metastases provide satisfactory short and long-term outcomes.

Abstract IA009: Tumor organoids of multi-metastatic colorectal cancer: From research tools to treatment decision tools

Most patients with colorectal cancer (CRC) do not have an “actionable” target based on molecular tumor profiling. Ex vivo drug sensitivity testing of tumor organoids holds promise as a complementary approach in precision oncology. We have established a pre-clinical pharmacogenomics platform for CRC at Oslo University Hospital. A living biobank of 208 organoids of distinct liver lesions from 100 patients treated by hepatic resection for metastatic CRC was generated in the observational phase of the project. Sensitivity testing of custom drug libraries (n=40-47 drugs) and molecular profiling (targeted DNA sequencing, RNA sequencing, multiplex immunohistochemistry) indicated that the organoids recapitulate well-known pharmacogenomic associations, phenotypic tumor features, and clinical treatment responses (n=35 patients published (ref 1,2)). Evaluation of multiple lesions (n=2-6) per patient suggested diversity among patients in the level of inter-metastatic heterogeneity of drug sensitivities, supporting the need for multi-tumor evaluations in a clinical setting. A collection of CRC cell lines (n=107) was screened for sensitivity to more than 500 drugs and this suggested a molecular basis for response to selected targeted agents, including to PARP inhibition in a small subset of the cell lines (ref 3). Combination screens suggested possibility to overcome acquired resistance to dual BRAF and EGFR blockade in BRAFV600E cells (unpublished data). The living biobank serves as a reference for drug nominations in an ongoing phase II umbrella trial of pharmacogenomics-guided treatment in patients with metastatic CRC (EVIDENT; EU Clinical Trials Register no. 2020-003395-41). Several ad hoc patient cases have been screened as a pilot for the trial, and data of clinical benefit from this functional precision oncology strategy will be presented. References: 1. Bruun J. et al. Patient-derived organoids from multiple colorectal cancer liver metastases reveal moderate intra-patient pharmacotranscriptomic heterogeneity. Clin Cancer Res 2020;26:4107-19. 2. Kryeziu K. et al. Increased sensitivity to SMAC mimetic LCL161 identified by longitudinal ex vivo pharmacogenomics of recurrent, KRAS mutated rectal cancer liver metastases. J. Transl Med 2021;19:384. 3. Smeby J. et al. Molecular correlates of sensitivity to PARP inhibition beyond homologous recombination deficiency in pre-clinical models of colorectal cancer point to wild-type TP53 activity. EBioMed 2020;59:102923.

Citation Format: Anita Sveen, Kushtrim Kryeziu, Solveig M.K. Klokkerud, Kaja C.G. Berg, Max Z. Totland, Christian H. Bergsland, Barbara Niederdorfer, Seyed H. Moosavi, Eva Hofsli, Morten Brændengen, Kristoffer Lassen, Arild Nesbakken, Sheraz Yaqub, Tormod K. Guren, Ragnhild A. Lothe. Tumor organoids of multi-metastatic colorectal cancer: From research tools to treatment decision tools [abstract]. In: Proceedings of the AACR Special Conference on Colorectal Cancer; 2022 Oct 1-4; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_1):Abstract nr IA009.

Laparoscopic versus open liver resection for intrahepatic cholangiocarcinoma: a multicenter propensity score-matched study

BACKGROUND

The role of laparoscopy in the treatment of intrahepatic cholangiocarcinoma (ICC) remains unclear. This multicenter study examined the outcomes of laparoscopic liver resection for ICC.

METHODS

Patients with ICC who had undergone laparoscopic or open liver resection between 2012 and 2019 at four European expert centers were included in the study. Laparoscopic and open approaches were compared in terms of surgical and oncological outcomes. Propensity score matching was used for minimizing treatment selection bias and adjusting for confounders (age, ASA grade, tumor size, location, number of tumors and underlying liver disease).

RESULTS

Of 136 patients, 50 (36.7%) underwent laparoscopic resection, whereas 86 (63.3%) had open surgery. Median tumor size was larger (73.6 vs 55.1 mm, p = 0.01) and the incidence of bi-lobar tumors was higher (36.6 vs 6%, p < 0.01) in patients undergoing open surgery. After propensity score matching baseline characteristics were comparable although open surgery was associated with a larger fraction of major liver resections (74 vs 38%, p < 0.01), lymphadenectomy (60 vs 20%, p < 0.01) and longer operative time (294 vs 209 min, p < 0.01). Tumor characteristics were similar. Laparoscopic resection resulted in less complications (30 vs 52%, p = 0.025), fewer reoperations (4 vs 16%, p = 0.046) and shorter hospital stay (5 vs 8 days, p < 0.01). No differences were found in terms of recurrence, recurrence-free and overall survival.

CONCLUSION

Laparoscopic resection seems to be associated with improved short-term and with similar long-term outcomes compared with open surgery in patients with ICC. However, possible selection criteria for laparoscopic surgery are yet to be defined.

Echinococcosis in a non-endemic country - 20-years' surgical experience from a Norwegian tertiary referral Centre

BACKGROUND

In Scandinavia, the incidence of cystic echinococcosis (CE) and alveolar echinococcosis (AE) is low and almost exclusively an imported disease following the trends of immigration. The aim of the study was to review available data on clinical management and outcome for patients treated at Oslo University Hospital, a referral centre for echinococcosis in Norway, with special emphasis on surgical treatment.

METHODS

All patients admitted with echinococcosis between January 2000 and December 2020 were identified. Medical records were reviewed retrospectively concerning patient demographics, treatment strategy, surgical procedures, complications and outcomes.

RESULTS

A total of 92 patients with median age 37 years (range 4-85) were identified. Sixty-eight patients (74%) were symptomatic. All patients, except for two, were immigrants to Norway and born in endemic areas. Ninety patients were diagnosed with CE and two with AE. Location of the cysts was most commonly in the liver (86%) followed by peritoneum, lungs, and spleen. All patients with active cysts were treated with albendazole. Surgical treatment was performed in 51 (56%) patients. The most common reason for abstaining from surgical treatment was that the diagnostic work-up revealed inactive cysts or interventional radiology was performed. Of the 51 patients who underwent surgery, a radical procedure was performed in 32 (64%) cases, a conservative procedure in 12 (24%), and a combination in six (12%). Clavien Dindo grade ≥3 complications occurred in 30%, and 90-day mortality was 2%. Bile leakage occurred in seven patients and was treated successfully with endoscopic retrograde cholangiopancreatography with biliary stent placement in all patients.

CONCLUSION

In a low-endemic area like Norway, management of echinococcus includes medical therapy, surgery, and/or interventional radiology. Surgical intervention seems to be effective, and is associated with acceptable morbidity rates.

Minimally Invasive Pancreatoduodenectomy: Contemporary Practice, Evidence, and Knowledge Gaps

Minimally invasive pancreatoduodenectomy has gained popularity throughout the last decade. For laparoscopic pancreatoduodenectomy, some high-level evidence exists, but with conflicting results. There are currently no published randomized controlled trials comparing robotic and open pancreatoduodenectomy. Comparative long-term data for patients with pancreatic ductal adenocarcinoma is lacking to date. Based on the existing evidence, current observed benefits of minimally invasive pancreatoduodenectomy over open pancreatoduodenectomy seem scarce, but retrospective data indicate the safety of these procedures in selected patients. As familiarity with the robotic platform increases, studies have shown an expansion in indications, also including patients with vascular involvement and even indicating favorable results in patients with obesity and high-risk morphometric features. Several ongoing randomized controlled trials aim to investigate potential differences in short- and long-term outcomes between minimally invasive and open pancreatoduodenectomy. Their results are much awaited.

Liver transplantation in patients with post-hepatectomy liver failure - A Northern European multicenter cohort study

BACKGROUND

Liver transplantation (LTX) has been described as a rescue treatment option in severe, intractable post-hepatectomy liver failure (PHLF), but is not considered to be indicated for this condition by many hepatobiliary and transplant surgeons. In this article we describe the clinical experience of five northern European tertiary centers in using LTX to treat selected patients with severe PHLF.

METHODS

All patients subjected to LTX due to PHLF at the participating centers were identified from prospective clinical databases. Preoperative variables, surgical outcome (both resection surgery and LTX) and follow-up data were assessed.

RESULTS

A total of 10 patients treated with LTX due to severe PHLF from September 2008 to May 2020 were identified and included in the study. All patients but one were male and the median age was 70 years (range 49-72). In all patients the indication for liver resection was suspected malignancy, but in six patients post-resection pathology revealed benign or pre-malignant disease. There was no 90-day mortality after LTX. Patients were followed for a median of 49 months (13-153) and eight patients were alive without recurrence at last follow-up.

DISCUSSION

In selected patients with PHLF LTX can be a life-saving procedure with low short-term risk.

Early detection of anastomotic leakage after pancreatoduodenectomy with microdialysis catheters: an observational Study

BACKGROUND

Microdialysis catheters can detect focal inflammation and ischemia, and thereby have a potential for early detection of anastomotic leakages after pancreatoduodenectomy. The aim was to investigate whether microdialysis catheters placed near the pancreaticojejunostomy can detect leakage earlier than the current standard of care.

METHODS

Thirty-five patients with a median age 69 years were included. Two microdialysis catheters were placed at the end of surgery; one at the pancreaticojejunostomy, and one at the hepaticojejunostomy. Concentrations of glucose, lactate, pyruvate, and glycerol were analyzed hourly in the microdialysate during the first 24 h, and every 2-4 h thereafter.

RESULTS

Seven patients with postoperative pancreatic fistulae (POPF) had significantly higher glycerol levels (P < 0.01) in the microdialysate already in the first postoperative samples. Glycerol concentrations >400 μmol/L during the first 12 postoperative hours detected patients with POPF with a sensitivity of 100% and a specificity of 93% (P < 0.001). After 24 h, lactate and lactate-to-pyruvate ratio were significantly higher (P < 0.05) and glucose was significantly lower (P < 0.05) in patients with POPF.

CONCLUSION

High levels of glycerol in microdialysate was an early detector of POPF. The subsequent inflammation was detected as increase in lactate and lactate-to-pyruvate ratio and a decrease in glucose (NCT03627559).

Single-cell transcriptomic analysis of human colonic macrophages reveals niche-specific subsets

Macrophages are a heterogeneous population of cells involved in tissue homeostasis, inflammation, and cancer. Although macrophages are densely distributed throughout the human intestine, our understanding of how gut macrophages maintain tissue homeostasis is limited. Here we show that colonic lamina propria macrophages (LpMs) and muscularis macrophages (MMs) consist of monocyte-like cells that differentiate into multiple transcriptionally distinct subsets. LpMs comprise subsets with proinflammatory properties and subsets with high antigen-presenting and phagocytic capacity. The latter are strategically positioned close to the surface epithelium. Most MMs differentiate along two trajectories: one that upregulates genes associated with immune activation and angiogenesis, and one that upregulates genes associated with neuronal homeostasis. Importantly, MMs are located adjacent to neurons and vessels. Cell–cell interaction and gene network analysis indicated that survival, migration, transcriptional reprogramming, and niche-specific localization of LpMs and MMs are controlled by an extensive interaction with tissue-resident cells and a few key transcription factors.

A young woman who did not awake after extensive surgery

BACKGROUND

Cystic echinococcosis (CE) caused by Echinococcus granulosus, significantly impacts health globally, but is a rare disease in Norway. CE is treated with a combination of anthelmintics and surgery, or percutaneous drainage.

CASE PRESENTATION

A woman in her thirties underwent extensive surgery due to disseminated CE in the abdominal cavity and liver. Due to intraoperative cyst rupture with contamination of the abdominal cavity, peritoneal lavage with hypertonic saline (20 % NaCl), a scolicidal agent, was performed for ten minutes before irrigation with physiological saline. Immediately after surgery, the patient was haemodynamically unstable and did not awake. Blood level of sodium was found to be severely increased at 188 mmol/L (ref 137−144 mmol/L). Hypotonic fluids (5 % glucose) were immediately administered intravenously to correct the acute hypernatraemia. CT scan of the head did not show signs of bleeding or oedema. The sodium level was normalised on postoperative day three and the patient was discharged without any neurological sequelae.

INTERPRETATION

Our patient developed iatrogenic acute severe hypernatraemia following abdominal lavage with hypertonic saline. Acute severe hypernatraemia is potentially lethal. Hypertonic saline must be used intraoperatively with great caution. Regular blood tests to detect hypernatraemia and monitor other electrolyte disturbances should be mandatory.

Aspirin as secondary prevention in colorectal cancer liver metastasis (ASAC trial): study protocol for a multicentre randomized placebo-controlled trial

Background

Colorectal cancer is one the most common cancers in the western world with increasing incidence. Approximately 50% of the patients develop liver metastases. Resection of liver metastases is the treatment of choice although almost half of the resected patients get recurrence in the liver.

Methods

The ASAC trial is a Scandinavian, multicentre, double-blinded, randomized, placebo-controlled study to determine whether adjuvant treatment with low-dose aspirin (acetylsalicylic acid (ASA)) can improve disease-free survival in patients treated for colorectal cancer liver metastases (CRCLM). Up to 800 patients operated for CRCLM will be randomized to Arm#1 ASA 160 mg once daily or Arm#2 Placebo, for a period of 3 years or until disease recurrence. The patients will be recruited at all major hepatobiliary surgical units in Norway, Sweden and Denmark and have follow-up according to standard of care and the National Guidelines.

Discussion

The ASAC trial will be the first clinical interventional trial to assess the potential beneficial role of ASA in recurrence of CRCLM and survival. ASA is an inexpensive, well-tolerated and easily accessible drug that will be highly potential as adjuvant drug in secondary prevention of CRCLM if the study shows a beneficial effect. We will also determine the effect of ASA as adjuvant treatment on Health-Related Quality of Life and the cost-effectiveness.

Trial registration

ClinicalTrials.gov NCT03326791. Registered on 31 October 2017.

A high-affinity human TCR-like antibody detects celiac disease gluten peptide-MHC complexes and inhibits T cell activation

Antibodies specific for peptides bound to human leukocyte antigen (HLA) molecules are valuable tools for studies of antigen presentation and may have therapeutic potential. Here, we generated human T cell receptor (TCR)-like antibodies toward the immunodominant signature gluten epitope DQ2.5-glia-α2 in celiac disease (CeD). Phage display selection combined with secondary targeted engineering was used to obtain highly specific antibodies with picomolar affinity. The crystal structure of a Fab fragment of the lead antibody 3.C11 in complex with HLA-DQ2.5:DQ2.5-glia-α2 revealed a binding geometry and interaction mode highly similar to prototypic TCRs specific for the same complex. Assessment of CeD biopsy material confirmed disease specificity and reinforced the notion that abundant plasma cells present antigen in the inflamed CeD gut. Furthermore, 3.C11 specifically inhibited activation and proliferation of gluten-specific CD4⁺ T cells in vitro and in HLA-DQ2.5 humanized mice, suggesting a potential for targeted intervention without compromising systemic immunity.

Liver resection and ablation for squamous cell carcinoma liver metastases

Background

Limited evidence exists to guide the management of patients with liver metastases from squamous cell carcinoma (SCC). The aim of this retrospective multicentre cohort study was to describe patterns of disease recurrence after liver resection/ablation for SCC liver metastases and factors associated with recurrence-free survival (RFS) and overall survival (OS).

Method

Members of the European–African Hepato-Pancreato-Biliary Association were invited to include all consecutive patients undergoing liver resection/ablation for SCC liver metastases between 2002 and 2019. Patient, tumour and perioperative characteristics were analysed with regard to RFS and OS.

Results

Among the 102 patients included from 24 European centres, 56 patients had anal cancer, and 46 patients had SCC from other origin. RFS in patients with anal cancer and non-anal cancer was 16 and 9 months, respectively (P = 0.134). A positive resection margin significantly influenced RFS for both anal cancer and non-anal cancer liver metastases (hazard ratio 6.82, 95 per cent c.i. 2.40 to 19.35, for the entire cohort). Median survival duration and 5-year OS rate among patients with anal cancer and non-anal cancer were 50 months and 45 per cent and 21 months and 25 per cent, respectively. For the entire cohort, only non-radical resection was associated with worse overall survival (hazard ratio 3.21, 95 per cent c.i. 1.24 to 8.30).

Conclusion

Liver resection/ablation of liver metastases from SCC can result in long-term survival. Survival was superior in treated patients with liver metastases from anal versus non-anal cancer. A negative resection margin is paramount for acceptable outcome.

Laparoscopic Distal Pancreatectomy Following Prior Upper Abdominal Surgery (Pancreatectomy and Prior Surgery)

BACKGROUND AND PURPOSE

Previous abdominal surgery can be a risk factor for perioperative complications in patients undergoing laparoscopic procedures. Today, distal pancreatectomy is increasingly performed laparoscopically. This study investigates the consequences of prior upper abdominal surgery (PUAS) for laparoscopic distal pancreatectomy (LDP).

METHODS

Patients who had undergone LDP from April 1997 to January 2020 were included. Based on the history and type of PUAS, these were categorized into three groups: minimally invasive (I), open (II), and no PUAS (III). To reduce possible confounding factors, the groups were matched in 1:2:4 fashion based on age, sex, body mass index (BMI) and American Society of Anesthesiology grade.

RESULTS

After matching, 30, 60, and 120 patients were included in the minimally invasive, open and no PUAS groups, respectively. No statistically significant differences were found in terms of intraoperative outcomes. Postoperative morbidity, mortality and length of hospital stay were similar. Open PUAS was associated with higher Comprehensive Complication Index (33.7 vs 20.9 vs 26.2, p = 0.03) and greater proportion of patients with ≥ 2 complications (16.7 vs 0 vs 6.7%, p = 0.02) compared with minimally invasive and no PUAS. Male sex, overweight (BMI 25-29.9 kg/m2), diagnosis of neuroendocrine neoplasia, and open PUAS were risk factors for severe morbidity in the univariable analysis. Only open PUAS was statistically significant in the multivariable model.

CONCLUSIONS

PUAS does not impair the feasibility and safety of LDP as its perioperative outcomes are largely comparable to those in patients without PUAS. However, open PUAS increases the burden and severity of postoperative complications.

Low Concordance Between T-Cell Densities in Matched Primary Tumors and Liver Metastases in Microsatellite Stable Colorectal Cancer

Background

The subtype, density and location of tumor infiltrating T-cells are being explored as prognostic and predictive biomarkers in primary colorectal cancer (pCRC) and colorectal liver metastases (CLM). Very limited data exist comparing findings in pCRC and matched CLM.

Patients and methods

Fifty-eight patients with available pCRC and matched CLM (57/58 microsatellite stable) were included in this OSLO-COMET substudy. In immunohistochemically stained sections, total (T_tot), helper (TH), cytotoxic (CTL), and regulatory (Treg) T-cells were manually counted in hotspots from the invasive margin (IM), intratumor (IT), and tumor adjacent regions to determine T-cell densities.

Results

A striking accumulation of T-cells was found in IM of both pCRC and CLM with much lower densities in the IT region, exemplified by T_tot of 2838 versus 340 cells/mm², respectively, in CLM. The correlation at the individual level between T-cell densities in pCRC and corresponding CLM was poor for all regions and T-cell subtypes; for instance, the correlation coefficient (R²) for IM T_tot was 0.07. The IT TH : CTL and Treg : TH ratios were 2.94 and 0.44, respectively, in pCRC, and 1.84 and 0.24, respectively, in CLM.

Conclusion

The observed accumulation of T-cells in the IM regions of pCRC and CLM with low penetration to the IT regions, combined with high TH : CTL and Treg : TH ratios, point to the presence of an immune suppressive microenvironment. T-cell densities of CLM differed markedly from the matched pCRC, indicating that to evaluate T-cell biomarkers in metastasis, the commonly available pCRC cannot serve as a surrogate for the metastatic tumor.

Survival Outcomes After Portal Vein Embolization and Liver Resection Compared With Liver Transplant for Patients With Extensive Colorectal Cancer Liver Metastases

Importance

Portal vein embolization (PVE) has been implemented in patients with extensive colorectal liver metastases to increase the number of patients able to undergo liver resection. Liver transplant could be an alternative in selected patients with extensive liver-only disease, and we have recently shown promising survival outcomes.

Objective

To compare overall survival (OS) among patients with colorectal cancer and high liver metastasis tumor load who were treated with liver transplant or with PVE and liver resection.

Design, Setting, and Participants

This comparative effectiveness research study assessed 50 patients with colorectal cancer liver metastases who were previously enrolled in liver transplant studies between November 2006 and August 2019 at Oslo University Hospital in Norway. Those patients were compared with a retrospective cohort of 53 patients in the Oslo University Hospital PVE database from March 2006 through November 2015 with similar selection criteria who underwent PVE and liver resection.

Main Outcomes and Measures

The OS among patients with high tumor load after liver transplant was compared with that among patients with high tumor load who underwent PVE and liver resection. High tumor load was defined as 9 or more metastatic tumors or a diameter of 5.5 cm or longer for the largest liver lesion.

Results

In the PVE cohort of 53 patients, the median age was 61.8 years (range, 34.3-71.3 years), and 36 patients (68%) were men. The 5-year OS rate among 38 patients who underwent liver resection after PVE was 44.6%. The 5-year OS rate for patients with high tumor load was 33.4% for those who underwent liver transplant and 6.7% for those who underwent PVE. Among patients with high tumor load and left-sided primary tumors, the 5-year OS rate was 45.3% for those receiving a liver allograft and 12.5% for those treated with PVE and liver resection.

Conclusions and Relevance

Patients with nonresectable disease, an extensive liver tumor load, and left-sided primary tumors had long OS after liver transplant, exceeding the survival outcome for those patients treated with PVE and liver resection.

Simultaneous Resection of Primary Colorectal Cancer and Synchronous Liver Metastases: Contemporary Practice, Evidence and Knowledge Gaps

The timing of surgical resection of synchronous liver metastases from colorectal cancer has been debated for decades. Several strategies have been proposed, but high-level evidence remains scarce. Simultaneous resection of the primary tumour and liver metastases has been described in numerous retrospective audits and meta-analyses. The potential benefits of simultaneous resections are the eradication of the tumour burden in one procedure, overall shorter procedure time, reduced hospital stay with the likely benefits on quality of life and an expected reduction in the use of health care services compared to staged procedures. However, concerns about accumulating complications and oncological outcomes remain and the optimal selection criteria for whom simultaneous resections are beneficial remains undetermined. Based on the current level of evidence, simultaneous resection should be restricted to patients with a limited liver tumour burden. More high-level evidence studies are needed to evaluate the quality of life, complication burden, oncological outcomes, as well as overall health care implications for simultaneous resections.

CD4+ T cells persist for years in the human small intestine and display a TH1 cytokine profile

Studies in mice and humans have shown that CD8⁺ T cell immunosurveillance in non-lymphoid tissues is dominated by resident populations. Whether CD4⁺ T cells use the same strategies to survey peripheral tissues is less clear. Here, examining the turnover of CD4⁺ T cells in transplanted duodenum in humans, we demonstrate that the majority of CD4⁺ T cells were still donor-derived one year after transplantation. In contrast to memory CD4⁺ T cells in peripheral blood, intestinal CD4⁺ T_RM cells expressed CD69 and CD161, but only a minor fraction expressed CD103. Functionally, intestinal CD4⁺ T_RM cells were very potent cytokine producers; the vast majority being polyfunctional T_H1 cells, whereas a minor fraction produced IL-17. Interestingly, a fraction of intestinal CD4⁺ T cells produced granzyme-B and perforin after activation. Together, we show that the intestinal CD4⁺ T-cell compartment is dominated by resident populations that survive for more than 1 year. This finding is of high relevance for the development of oral vaccines and therapies for diseases in the gut.

Laparoscopic Lavage vs Primary Resection for Acute Perforated Diverticulitis: Long-term Outcomes From the Scandinavian Diverticulitis (SCANDIV) Randomized Clinical Trial

Importance

Perforated colonic diverticulitis usually requires surgical resection, with significant morbidity. Short-term results from randomized clinical trials have indicated that laparoscopic lavage is a feasible alternative to resection. However, it appears that no long-term results are available.

Objective

To compare long-term (5-year) outcomes of laparoscopic peritoneal lavage and primary resection as treatments of perforated purulent diverticulitis.

Design, Setting, and Participants

This international multicenter randomized clinical trial was conducted in 21 hospitals in Sweden and Norway, which enrolled patients between February 2010 and June 2014. Long-term follow-up was conducted between March 2018 and November 2019. Patients with symptoms of left-sided acute perforated diverticulitis, indicating urgent surgical need and computed tomography-verified free air, were eligible. Those available for trial intervention (Hinchey stages <IV) were included in the long-term follow-up.

Interventions

Patients were assigned to undergo laparoscopic peritoneal lavage or colon resection based on computer-generated, center-stratified block randomization.

Main Outcomes and Measures

The primary outcome was severe complications within 5 years. Secondary outcomes included mortality, secondary operations, recurrences, stomas, functional outcomes, and quality of life.

Results

Of 199 randomized patients, 101 were assigned to undergo laparoscopic peritoneal lavage and 98 were assigned to colon resection. At the time of surgery, perforated purulent diverticulitis was confirmed in 145 patients randomized to lavage (n = 74) and resection (n = 71). The median follow-up was 59 (interquartile range, 51-78; full range, 0-110) months, and 3 patients were lost to follow-up, leaving a final analysis of 73 patients who had had laparoscopic lavage (mean [SD] age, 66.4 [13] years; 39 men [53%]) and 69 who had received a resection (mean [SD] age, 63.5 [14] years; 36 men [52%]). Severe complications occurred in 36% (n = 26) in the laparoscopic lavage group and 35% (n = 24) in the resection group (P = .92). Overall mortality was 32% (n = 23) in the laparoscopic lavage group and 25% (n = 17) in the resection group (P = .36). The stoma prevalence was 8% (n = 4) in the laparoscopic lavage group vs 33% (n = 17; P = .002) in the resection group among patients who remained alive, and secondary operations, including stoma reversal, were performed in 36% (n = 26) vs 35% (n = 24; P = .92), respectively. Recurrence of diverticulitis was higher following laparoscopic lavage (21% [n = 15] vs 4% [n = 3]; P = .004). In the laparoscopic lavage group, 30% (n = 21) underwent a sigmoid resection. There were no significant differences in the EuroQoL-5D questionnaire or Cleveland Global Quality of Life scores between the groups.

Conclusions and Relevance

Long-term follow-up showed no differences in severe complications. Recurrence of diverticulitis after laparoscopic lavage was more common, often leading to sigmoid resection. This must be weighed against the lower stoma prevalence in this group. Shared decision-making considering both short-term and long-term consequences is encouraged.

Trial Registration

ClinicalTrials.gov Identifier: NCT01047462.

Risk of colorectal cancer following CT-verified acute diverticulitis: a nationwide population-based cohort study

AIM

Routine colonoscopy to exclude colorectal cancer (CRC) after CT-verified acute diverticulitis is controversial. This study aimed to compare the incidence of CRC in patients with acute diverticulitis with that in the general population.

METHOD

Patients with an emergency admission for diverticular disease to any Norwegian hospital between 1 January 2008 and 31 December 2010 were included through identification in the Norwegian Patient Registry using International Classification of Diseases (ICD-10) codes K57.1-9. To estimate the age-specific distribution of CT-verified acute uncomplicated diverticulitis (AUD) and acute complicated diverticulitis (ACD) in this nationwide study population, numbers from the largest Norwegian emergency hospital were used. Patients diagnosed with CRC within 1 year following their admission for acute diverticulitis were detected through cross-matching with the Cancer Registry of Norway. Based on both Norwegian age-specific incidence of CRC and estimated age-specific distribution of CT-verified diverticulitis, standard morbidity ratios (SMRs) were calculated.

RESULTS

A total of 7473 patients with emergency admissions for diverticular disease were identified (estimated CT-verified AUD n = 3523, ACD n = 1206); of these 155 patients were diagnosed with CRC within 1 year. Eighty had a CT-verified diverticulitis at index admission [41 AUD (51.3%); 39 ACD (49.7%)]. Compared with the general population, the SMR was 6.6 following CT-verified AUD and 16.3 following ACD, respectively.

CONCLUSION

In the first year after CT-verified acute diverticulitis, especially after ACD, the risk of CRC is higher than in the general population. This probably represents misdiagnosis of CRC as acute diverticulitis. Follow-up colonoscopy should be recommended to all patients admitted with acute diverticulitis.

Abstract B46: Gene expression in colorectal liver metastases: Distinct immune signatures and opportunities for immune modulating therapy

Colorectal cancer (CRC) is one of the most common cancers and a leading cause of cancer death in the Western world. Up to 50% of CRC patients develop metastatic disease and the liver is the most common site. The recently identified consensus molecular subtypes (CMS1-4) based on analyses of primary CRC have prognostic and therapeutic implications, but it is unclear whether these molecular subtypes are valid for metastatic disease. The tumor microenvironment plays a major role in the dynamic shaping of the tumor phenotype and the clinical impact of the immune contexture within given CMS subgroups is emerging. In this study we performed gene expression profiling of a CLM cohort for patient stratification. Surgically resected CLMs (n=44) were analyzed by genome-wide transcription profiling. Clustering approaches were applied to define subgroups. Differential gene expression analyses were performed to reveal altered expression patterns in subgroups selected by clinicopathologic parameters. Functional annotation of gene signatures was conducted. Validation in public data sets and by proteomic analyses (RPPA) is ongoing. Quantification of T-cell subsets by immunohistochemistry was scored. The CMS classifier tool revealed the cohort to be highly enriched for CMS2 and thus of limited stratification utility. In contrast, intrinsic subgroups were revealed by alternative computational approaches. Distinct immune profiles were associated with the subgroups identified. Unsupervised clustering based on high-variance genes identified a 55-gene cluster that split the cohort near evenly. Functional annotation of the 55 genes identified one subgroup to display dysregulated cholesterol/lipid homeostasis with reciprocal links to immune regulatory genes. Supervised clustering using EMT/mesenchymal signatures identified a mesenchymal subgroup (20% of the samples). Functional annotation suggested coexistence of immunosuppression with the mesenchymal phenotype. Elevated expression of immune checkpoint molecules including TIM-3, and M2 macrophage markers correlated with the EMT/mesenchymal signature. The subgroup showed relative high density of T-cell subset infiltration (CD3, CD4, CD8, FOXP3). In differential gene expression analysis, CLMs exposed to neoadjuvant chemotherapy showed activation of interferon gamma (IFNG) signaling and genes linked to immunogenic cell death. Co-expression of immune regulatory genes suggested counterbalance of the immune responses triggered by IFNG. Immune-related gene expression signatures were associated with the CLM subgroups identified. These observations underline the integration and importance of the immune interactome in CLM. The coordinated expression of immunosuppressive factors suggests not only a rationale for immune therapy, but also that development of immune-modulating strategies may be required to increase efficacy of current therapy for selected CLM patients.

Citation Format: Vigdis Nygaard, Vegar Johansen Dagenborg, Sheraz Yaqub, Åsmund Avdem Fretland, Olga Østrup, Laxmi Siwal-Pandit, Krzysztof Grzyb, Anne-Lise Børresen-Dale, Gunhild Mari Mælandsmo, Anne Hansen Ree, Bjørn Edwin, Kjersti Flatmark. Gene expression in colorectal liver metastases: Distinct immune signatures and opportunities for immune modulating therapy [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B46.

Neoadjuvant chemotherapy is associated with a transient increase of intratumoral T-cell density in microsatellite stable colorectal liver metastases

Patients with colorectal liver metastases (CLM) commonly receive neoadjuvant chemotherapy (NACT) prior to surgical resection. NACT may induce immunogenic cell death with subsequent recruitment of T-cells to the tumor microenvironment, which could be exploited by immune checkpoint inhibition (ICI). In theory, this could expand the use of ICI to obtain responses also in microsatellite stable colorectal cancer, but evidence to suggest optimal treatment schedules are lacking. In this study, densities of total-, cytotoxic-, helper- and regulatory T-cells were quantified by immunohistochemistry in resected CLM from 92 patients included in the OSLO-COMET trial (NCT01516710). All but one patient had microsatellite stable tumors (91/92). Associations between T-cell densities and clinicopathological parameters were analyzed. Fluoropyrimidine-based NACT (in most cases with addition of oxaliplatin or irinotecan) was administered to 45 patients completed median 8 weeks prior to surgical resection. No overall association was found between NACT administration and intratumoral T-cell densities. However, within the NACT group, a short time interval (<9.5 weeks) between NACT completion and CLM resection was strongly associated with high intratumoral T-cell densities compared to the long-interval and no NACT groups (medians 491, 236, and 292 cells/mm², respectively; P < .0001). The results from this study suggest that the observed increase in intratumoral T-cells after NACT administration may be transient. The significance of this finding should be further explored to ensure that optimal treatment schedules are chosen for studies combining cytotoxic chemotherapy and ICI.

Survey of the attitudes of hepatopancreatobiliary surgeons in northern Europe to resection of choledochal cysts in asymptomatic Western adults

Background

Todani type 1 and 4 choledochal cysts are associated with a risk of developing cholangiocarcinoma. Resection is usually recommended, but data for asymptomatic Western adults are sparse. The aim of this study was to investigate diagnostic interpretation and attitudes towards resection of bile ducts for choledochal cysts in this subgroup of patients across northern European centres.

Methods

Thirty hepatopancreatobiliary centres were provided with magnetic resonance cholangiopancreatograms and asked to discuss the management of six cases: asymptomatic non‐Asian women, aged 30 or 60 years, with variable common bile duct (CBD) dilatations and different risk factors in the setting of a multidisciplinary team (MDT). The Fleiss κ value was calculated to estimate overall inter‐rater agreement.

Results

For all case scenarios combined, 83·3 and 86·7 per cent recommended resection for a CBD of 20 and 26 mm respectively, compared with 19·4 per cent for a CBD of 13 mm (P < 0·001). For patients aged 30 and 60 years, resection was recommended in 68·5 and 57·8 per cent respectively (P = 0·010). There was a trend towards recommending resection in the presence of a common channel, most pronounced in the 60‐year‐old patient. High amylase levels in the CBD aspirate led to recommendations to resect, but only for the 13‐mm CBD dilatation. There were no differences related to centre size or region. MDT discussion was associated with recommendations to resect. Inter‐rater agreement was 73·3 per cent (κ = 0·43, 95 per cent c.i. 0·38 to 0·48).

Conclusion

The inter‐rater agreement to resect was intermediate, and the recommendation was dependent mainly on the diameter of the CBD dilatation.

Resident memory CD8 T cells persist for years in human small intestine

Bartolomé-Casado et al. demonstrate that human gut contains large numbers of resident memory CD8 T cells that survive for years. Intestinal CD8 Trm cells have a clonally expanded immune repertoire that is stable over time and exhibit enhanced protective capabilities.

Resident memory CD8 T (Trm) cells have been shown to provide effective protective responses in the small intestine (SI) in mice. A better understanding of the generation and persistence of SI CD8 Trm cells in humans may have implications for intestinal immune-mediated diseases and vaccine development. Analyzing normal and transplanted human SI, we demonstrated that the majority of SI CD8 T cells were bona fide CD8 Trm cells that survived for >1 yr in the graft. Intraepithelial and lamina propria CD8 Trm cells showed a high clonal overlap and a repertoire dominated by expanded clones, conserved both spatially in the intestine and over time. Functionally, lamina propria CD8 Trm cells were potent cytokine producers, exhibiting a polyfunctional (IFN-γ⁺ IL-2⁺ TNF-α⁺) profile, and efficiently expressed cytotoxic mediators after stimulation. These results suggest that SI CD8 Trm cells could be relevant targets for future oral vaccines and therapeutic strategies for gut disorders.