Impact of spatio-temporal recurrence pattern on overall survival for invasive intraductal papillary mucinous neoplasia - A comparison with pancreatic ductal adenocarcinoma

BACKGROUND

Resections for intraductal papillary mucinous neoplasia (IPMN) have increased dramatically during the last decade. Recurrence pattern and impact of adjuvant chemotherapy for solid pancreatic ductal adenocarcinoma (PDAC) is well known, but not for invasive IPMN (inv-IPMN).

OBJECTIVES

To elucidate the impact of spatio-temporal recurrence pattern and adjuvant chemotherapy on overall survival for inv-IPMN compared with PDAC.

METHODS

We conducted a retrospective single-center observational study of consecutive patients ≥18 years of age who underwent resection for inv-IPMN or PDAC at Karolinska University Hospital, between 2009 and 2018. Different initial recurrence sites and time frames as well as predictors for death were assessed with multivariable Cox and logistic regressions. Survival analyses were performed using the Kaplan-Meier model and log rank test.

RESULTS

Of 396 resected patients, 92 were inv-IPMN and 304 PDAC. Both recurrence rate and death rate within three-years were lower for inv-IPMN compared to PDAC (p = 0.006 and p = 0.007 respectively). Across the whole cohort, the most common recurrence patterns were multi-site (25%), single-site liver (21%) and single-site locoregional (10%) recurrence. The most prominent predictors for death in multivariable Cox regression, especially if occurred within the first year, were multi-site (HR 17.0), single-site peritoneal (HR 13.6) and single-site liver (HR 13.1) recurrence. These predictors were less common in inv-IPMN compared to PDAC (p = 0.007). The effect of adjuvant chemotherapy was similar in the two groups.

CONCLUSION

Resected inv-IPMN exhibits a less aggressive recurrence pattern than PDAC that translates into a more favorable overall survival.

TLR9 signalling inhibits Plasmodium liver infection by macrophage activation

Recognition of pathogen-associated molecular patterns (PAMPs) through Toll-like receptors (TLRs) plays a pivotal role in first-line pathogen defense. TLRs are also likely triggered during a Plasmodium infection in vivo by parasite-derived components. However, the contribution of innate responses to liver infection and to the subsequent clinical outcome of a blood infection is not well understood. To assess the potential effects of enhanced TLR-signalling on Plasmodium infection, we systematically examined the effect of agonist-primed immune responses to sporozoite inoculation in the P. berghei/C57Bl/6 murine malaria model. We could identify distinct stage-specific effects on the course of infection after stimulation with two out of four TLR-ligands tested. Priming with a TLR9 agonist induced killing of pre-erythrocytic stages in the liver that depended on macrophages and the expression of inducible nitric oxide synthase (iNOS). These factors have previously not been recognized as antigen-independent effector mechanisms against Plasmodium liver stages. Priming with TLR4 and -9 agonists also translated into blood stage-specific protection against experimental cerebral malaria (ECM). These insights are relevant to the activation of TLR signalling pathways by adjuvant systems of antimalaria vaccine strategies. The protective role of TLR4-activation against ECM might also explain some unexpected clinical effects observed with pre-erythrocytic vaccine approaches.

Extracellular vesicles are the primary source of blood-borne tumour-derived mutant KRAS DNA early in pancreatic cancer

Up to now, the field of liquid biopsies has focused on circulating tumour DNA and cells, though extracellular vesicles (EVs) have been of increasing interest in recent years. Thus, reported sources of tumour-derived nucleic acids include leukocytes, platelets and apoptotic bodies (AB), as well as large (LEV) and small (SEV) EVs. Despite these competing claims, there has yet to be a standardized comparison of the tumour-derived DNA associated with different components of blood. To address this issue, we collected twenty-three blood samples from seventeen patients with pancreatic cancers of known mutant KRAS G12 genotype, and divided them into two groups based on the time of patient survival following sampling. After collecting red and white blood cells, we subjected 1 ml aliquots of platelet rich plasma to differential centrifugation in order to separate the platelets, ABs, LEVs, SEVs and soluble proteins (SP) present. We then confirmed the enrichment of specific blood components in each differential centrifugation fraction using electron microscopy, Western blotting, nanoparticle tracking analysis and bead-based multiplex flow cytometry assays. By targeting wild type and tumour-specific mutant KRAS alleles using digital PCR, we found that the levels of mutant KRAS DNA were highest in association with LEVs and SEVs early, and with SEVs and SP late in disease progression. Importantly, we established that SEVs were the most enriched in tumour-derived DNA throughout disease progression, and verified this association using size exclusion chromatography. This work provides important direction for the rapidly expanding field of liquid biopsies by supporting an increased focus on EVs as a source of tumour-derived DNA.

Plasma protein biomarkers for early detection of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis, mainly due to late diagnosis at advanced tumor stages. In this study, we aimed to identify plasma protein biomarkers for early detection of PDAC. Totally, 135 PDAC patients (early PDAC, Stage I/II, n = 71; advanced PDAC, Stage III/IV, n = 64), 13 benign lesions/chronic pancreatitis patients and 72 healthy individuals, with corresponding plasma samples from a case-control study in Sweden were included. A proximity extension assay was used to detect 92 cancer-related proteins, and an enzyme-linked immunosorbent assay/electrochemiluminescence immunoassay was used to detect CA19-9. Predictive features were selected from these 93 candidate proteins and three covariates in the Swedish participants, and then validated in Spanish participants, including 37 early PDAC patients, 38 advanced PDAC patients, 19 chronic pancreatitis patients and 36 healthy controls. A panel of eight proteins discriminating early PDAC from healthy individuals was identified, and the cross-validated area under the curves (AUCs) were 0.85 (95% confidence interval, 95% CI, 0.78-0.91) and 0.81 (95% CI, 0.70-0.92) in the Swedish and Spanish participants, respectively. Another eight-protein panel was predictive for classifying advanced PDAC from healthy controls in two populations, with cross-validated AUCs of 0.89 (95% CI, 0.83-0.95) and 0.90 (95% CI, 0.83-0.98), respectively. In conclusion, eight protein biomarkers were identified and externally validated, potentially allowing early detection of PDAC patients if validated in additional prospective studies.

Risk of Developing Pancreatic Cancer in Patients with Chronic Pancreatitis

Background: Patients with chronic pancreatitis (CP) have an increased risk of developing pancreatic ductal adenocarcinoma (PDAC). We present data on PDAC in one of the most extensive European single-centre cohort studies of patients with CP. Methods: Retrospective analysis of prospectively collected data of patients with CP was performed. Aetiology of CP was determined according to the M-ANNHEIM classification system and only patients with definite CP > 18 years at data analysis were included. The final dataset included 581 patients with definite CP diagnosed between 2003 and 2018. Results: At CP diagnosis, there were 371 (63.9%) males and 210 (36.1%) females (median age 57 years, range 2–86). During 3423 person-years of observation, six pancreatic cancers were diagnosed (0.2% year). The mean time between diagnosis of CP and the occurrence of PDAC was 5.0 years (range 2.7–8.6). None of the cancer patients had a family history of PDAC. Diabetes mellitus (DM) was present in five of six (83.3%) patients with PDAC: in three patients before and in two after CP diagnosis. Clinical/laboratory signs of pancreatic exocrine insufficiency (PEI) were present in five of six (83.3%) patients with PDAC: in two at diagnosis of CP and in three after diagnosis. The mean survival time was 4 months after the diagnosis of PDAC (range 0.5–13). PDAC occurred significantly more often (p < 0.001) in two groups of patients without previous acute pancreatitis (AP): 2 of 20 patients (10%) with low body mass index (BMI) and PEI and in 3 of 10 (30%) patients with high BMI and DM at diagnosis of CP. Conclusions: Patients with CP have a high risk of developing PDAC, although risk is low in absolute terms. Our data suggest the possibility of defining subgroups of patients with a particularly elevated risk of PDAC. Such a possibility would open a path to personalised decision making on initiation of PDAC surveillance of patients with no previous episode of AP, (i) with low BMI and PEI, or (ii) elevated BMI and DM.

Recent Discoveries of Diagnostic, Prognostic and Predictive Biomarkers for Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease with a dismal prognosis that is frequently diagnosed at an advanced stage. Although less common than other malignant diseases, it currently ranks as the fourth most common cause of cancer-related death in the European Union with a five-year survival rate of below 9%. Surgical resection, followed by adjuvant chemotherapy, remains the only potentially curative treatment but only a minority of patients is diagnosed with locally resectable, non-metastatic disease. Patients with advanced disease are treated with chemotherapy but high rates of treatment resistance and unfavorable side-effect profiles of some of the used regimens remain major challenges. Biomarkers reflect pathophysiological or physiological processes linked to a disease and can be used as diagnostic, prognostic and predictive tools. Thus, accurate biomarkers can allow for better patient stratification and guide therapy choices. Currently, the only broadly used biomarker for PDAC, CA 19-9, has multiple limitations and the need for novel biomarkers is urgent. In this review, we highlight the current situation, recent discoveries and developments in the field of biomarkers of PDAC and their potential clinical applications.

Respect - A multicenter retrospective study on preoperative chemotherapy in locally advanced and borderline resectable pancreatic cancer

BACKGROUND

Neoadjuvant chemotherapy has become a powerful tool to convert borderline resectable (BRPC) and locally advanced pancreatic cancers (LAPC) into a resectable scenario. However, data analyzing the optimal type of therapy are scarce. In the present multicenter retrospective study, we evaluated the influence of FOLFIRINOX (FFX) and gemcitabine (GEM)-based neoadjuvant therapy on patient prognosis.

METHODS

Data on 239 patients from 7 centers across Europe was gathered using an online database. Patients having received their first cycle of chemotherapy for BRPC/LAPC before 06/2017, with a minimum follow-up of 12 months, were included in the intention-to-treat analysis.

RESULTS

Patients treated with neoadjuvant FFX (n = 135) or gemcitabine + nab-paclitaxel (GNP) (n = 38) had significantly improved radiological response according to RECIST criteria as compared to single-agent GEM (n = 16), with a partial/complete response of 59.3%, 55.3% and 6.25% respectively (p = 0.001). Treatment with FFX (n = 135) and GNP (n = 38) resulted in higher resection rates compared to GEM (73.3%, 81.6% and 43.8%; p = 0.01 and p = 0.005). Regardless of regimen, patients who were resected had significantly prolonged overall survival compared to non-resected patients (p < 0.01). Complete pathological responses (ypT0 ypN0) were predominantly observed with FFX (p = 0.01). Adjuvant GNP in addition to successful neoadjuvant therapy and surgery resulted in a trend towards improved median survival as compared to postoperative observation (47.0 vs. 30.1 months, p = 0.06).

CONCLUSIONS

Representing one of the largest studies published so far, our results reveal that patients with BRPC/LAPC should be offered either FFX or GNP to improve chances of resection and with this also survival.

Variations in the management of diarrhoea induced by cancer therapy: results from an international, cross-sectional survey among European oncologists

Background

Chemotherapy-induced diarrhoea (CID) is a common side effect of cancer treatment. While cytotoxic agents are the main cause of CID, targeted drugs, immunotherapy and radiotherapy can also cause diarrhoea. Patients with severe CID often require hospital admission for intravenous fluid resuscitation and supportive treatment. In other patient populations, such as children with infectious diarrhoea, therapy is based on evidence from randomised-controlled clinical trials. In contrast, few trials have investigated CID management, and hence, treatment guidelines are largely based on expert opinion.

Methods

We conducted an online survey on CID management and institutional routines across Europe to obtain a more detailed picture of current practice in CID treatment. We analysed the responses from a total of 156 clinicians from 83 different medical centres in 31 countries.

Results

CID (any grade) is recognised as a common clinical problem in patients undergoing antitumoral treatment and it can require hospital admission in a substantial subgroup of patients. There is a strong consensus among clinicians as to the choice of resuscitation strategies and drug treatment for severe CID; 85.9% (n=134) of all respondents prefer intravenous crystalloid fluids and 95.5% (n=149) routinely use loperamide. In sharp contrast, we have identified disparities in the use of bowel rest in CID; approximately half of all participants (57.7%; n=90) consider bowel rest in initial CID management, while the remainder (42.3%; n=66) does not.

Conclusions

As previous studies have shown that bowel rest is associated with adverse outcomes in diarrhoea due to causes other than chemotherapy, the results from this survey suggest that further research is needed as to its role in CID.

Survival Benefits of Chemotherapy for Patients with Advanced Pancreatic Cancer in A Clinical Real-World Cohort

Clinical outcomes of chemotherapy for patients with advanced pancreatic adenocarcinoma in a real-world setting might differ from outcomes in randomized clinical trials (RCTs). Here we show in a single-institution cohort of 595 patients that median overall survival (OS) of patients who received gemcitabine alone (n = 185; 6.6 months (95% CI; 5.5–7.7)) was the same as in pivotal RCTs. Gemcitabine/capecitabine (n = 60; 10.6 months (95% CI; 7.8–13.3)) and gemcitabine/nab-paclitaxel (n = 66; 9.8 months (95% CI; 7.9–11.8)) resulted in a longer median OS and fluorouracil/oxaliplatin/irinotecan (n = 31, 9.9 months (95% CI; 8.1–11.7)) resulted in a shorter median OS than previously reported. Fluorouracil/oxaliplatin (n = 35, 5.8 months (95% CI; 4.5–7)) and best supportive care (n = 206, 1.8 months (95% CI; 1.5–2.1)) could not be benchmarked against any RCTs. The degree of protocol adherence explained differences between real-world outcomes and the respective RCTs, while exposure to second-line treatments did not.

Cooperation of BRAF(F595L) and mutant HRAS in histiocytic sarcoma provides new insights into oncogenic BRAF signaling

Activating BRAF mutations, in particular V600E/K, drive many cancers and are considered mutually exclusive with mutant RAS, whereas inactivating BRAF mutations in the D(594)F(595)G(596) motif cooperate with RAS via paradoxical MEK/ERK activation. Due to the increasing use of comprehensive tumor genomic profiling, many non-V600 BRAF mutations are being detected whose functional consequences and therapeutic actionability are often unknown. We investigated an atypical BRAF mutation, F595L, which was identified along with mutant HRAS in histiocytic sarcoma and also occurs in epithelial cancers, melanoma and neuroblastoma, and determined its interaction with mutant RAS. Unlike other DFG motif mutants, BRAF(F595L) is a gain-of-function variant with intermediate activity that does not act paradoxically, but nevertheless cooperates with mutant RAS to promote oncogenic signaling, which is efficiently blocked by pan-RAF and MEK inhibitors. Mutation data from patients and cell lines show that BRAF(F595L), as well as other intermediate-activity BRAF mutations, frequently coincide with mutant RAS in various cancers. These data define a distinct class of activating BRAF mutations, extend the spectrum of patients with systemic histiocytoses and other malignancies who are candidates for therapeutic blockade of the RAF-MEK-ERK pathway and underscore the value of comprehensive genomic testing for uncovering the vulnerabilities of individual tumors.

Fosmidomycin uptake into Plasmodium and Babesia-infected erythrocytes is facilitated by parasite-induced new permeability pathways

Background

Highly charged compounds typically suffer from low membrane permeability and thus are generally regarded as sub-optimal drug candidates. Nonetheless, the highly charged drug fosmidomycin and its more active methyl-derivative FR900098 have proven parasiticidal activity against erythrocytic stages of the malaria parasite Plasmodium falciparum. Both compounds target the isoprenoid biosynthesis pathway present in bacteria and plastid-bearing organisms, like apicomplexan parasites. Surprisingly, the compounds are inactive against a range of apicomplexans replicating in nucleated cells, including Toxoplasma gondii.

Methodology/Principal Findings

Since non-infected erythrocytes are impermeable for FR90098, we hypothesized that these drugs are taken up only by erythrocytes infected with Plasmodium. We provide evidence that radiolabeled FR900098 accumulates in theses cells as a consequence of parasite-induced new properties of the host cell, which coincide with an increased permeability of the erythrocyte membrane. Babesia divergens, a related parasite that also infects human erythrocytes and is also known to induce an increase in membrane permeability, displays a similar susceptibility and uptake behavior with regard to the drug. In contrast, Toxoplasma gondii-infected cells do apparently not take up the compounds, and the drugs are inactive against the liver stages of Plasmodium berghei, a mouse malaria parasite.

Conclusions/Significance

Our findings provide an explanation for the observed differences in activity of fosmidomycin and FR900098 against different Apicomplexa. These results have important implications for future screens aimed at finding new and safe molecular entities active against P. falciparum and related parasites. Our data provide further evidence that parasite-induced new permeability pathways may be exploited as routes for drug delivery.