Precision Medicine in Pancreatic Ductal Adenocarcinoma: The Impact of Targeted Therapies on Survival of Patients Harboring Actionable Mutations

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of death by cancer worldwide. Mostly diagnosed with locally advanced or metastatic disease, patients lack treatment options. Gene alterations (GAs) are frequently observed in PDAC, some of which are considered for molecular targeted therapies (MTTs), with potential clinical benefits and improved outcomes. However, the applicability of molecular profiling (MP) for precision medicine in PDAC remains to be demonstrated.

METHODS

We conducted a retrospective analysis of all patients, aged ≥18 years with histologically confirmed PDAC, who underwent tumor MP between 2010 and 2020 in our institution as part of personalized medicine trials. The primary study endpoint was overall survival (OS), and (minimal follow-up was 6 months after MP).

RESULTS

Of 115 eligible patients, MP was successful in 102 patients (89%). KRAS mutations were the most frequent GAs, mostly G12D. Based on ESCAT classification, actionable GAs were found in 29 patients (28%), involving mainly BRCA1 or BRCA2 (5 (18%)), HER2 (5 (18%)), MTAP (5 (18%)), and FGFR (3 (11%)). Only 12 of these 29 patients (41%, or 10% of the whole population) received MTTs, with a median progression-free survival of 1.6 months. Median OS was 19 months in patients with actionable GAs treated with MTTs (n = 12 (11.8%)), 14 months in patients with actionable GAs treated with standard therapies (n = 17 (16.7%)), and 17 months in patients without actionable GAs treated with standard therapies (n = 73 (71.5%); p = 0.26). The absence of liver metastases was associated with better OS (HR = 0.471, p = 0.01). The highest OS following MTT was observed in patients with BRCA mutations treated with olaparib.

INTERPRETATION

Actionable GAs were found in more than a quarter of patients with advanced PDAC. Overall, targeting actionable GAs with MTTs was not associated with improved OS in this retrospective study with limited patient numbers. However, selected GA/MTT combinations (e.g., BRCA mutations/olaparib) were associated with a better outcome.

The PRSS3P2 and TRY7 deletion copy number variant modifies risk for chronic pancreatitis

BACKGROUND

PRSS1 and PRSS2 constitute the only functional copies of a tandemly-arranged five-trypsinogen-gene cluster (i.e., PRSS1, PRSS3P1, PRSS3P2, TRY7 and PRSS2) on chromosome 7q35. Variants in PRSS1 and PRSS2, including missense and copy number variants (CNVs), have been reported to predispose to or protect against chronic pancreatitis (CP). We wondered whether a common trypsinogen pseudogene deletion CNV (that removes two of the three trypsinogen pseudogenes, PRSS3P2 and TRY7) might be associated with CP causation/predisposition.

METHODS

We analyzed the common PRSS3P2 and TRY7 deletion CNV in a total of 1536 CP patients and 3506 controls from France, Germany, India and Japan by means of quantitative fluorescent multiplex polymerase chain reaction.

RESULTS

We demonstrated that the deletion CNV variant was associated with a protective effect against CP in the French, German and Japanese cohorts whilst a trend toward the same association was noted in the Indian cohort. Meta-analysis under a dominant model yielded a pooled odds ratio (OR) of 0.68 (95% confidence interval (CI) 0.52-0.89; p = 0.005) whereas an allele-based meta-analysis yielded a pooled OR of 0.84 (95% CI 0.77-0.92; p = 0.0001). This protective effect is explicable by reference to the recent finding that the still functional PRSS3P2/TRY7 pseudogene enhancers upregulate pancreatic PRSS2 expression.

CONCLUSIONS

The common PRSS3P2 and TRY7 deletion CNV was associated with a reduced risk for CP. This finding provides additional support for the emerging view that dysregulated PRSS2 expression represents a discrete mechanism underlying CP predisposition or protection.

Investigating liver stiffness and viscosity for fibrosis, steatosis and activity staging using shear wave elastography

BACKGROUND & AIMS

Quantitative shear wave elastography was shown to be an effective tool for the non-invasive diagnosis and staging of chronic liver diseases. The liver shear modulus, estimated from the propagation velocity of shear waves, is correlated to the degree of fibrosis and can therefore be used for the non-invasive staging of fibrosis.

METHODS

We performed a clinical prospective study in a total of 120 patients with various chronic liver diseases to compare the accuracy of supersonic shear imaging (SSI), a technique based on acoustic radiation and ultrafast ultrasound imaging, to 1D transient elastography (FibroScan) for the staging and grading of fibrosis as assessed by liver biopsy. Since shear wave propagation spectroscopy can also provide additional mechanical information on soft tissues, such as viscosity, we also investigated those new mechanical parameters as possible predictors of fibrosis, steatosis, and disease activity.

RESULTS

SSI was successfully performed in 98.3% of patients and it was shown to be as accurate as FibroScan for the staging of fibrosis both for the whole population (N=120) and for the subgroup with viral hepatitis (n=70) (AUC=0.85 [0.77-0.96] and 0.89 [0.81-0.97] for significant fibrosis, AUC=0.90 [0.83-0.97] and 0.87 [0.75-0.98] for cirrhosis, with respect to SSI [n=68/70] and FibroScan [n=66/68]). Viscosity could also be used to stage the degree of fibrosis (AUC=0.76 [0.64-0.87] for significant fibrosis and AUC=0.87 [0.74-0.99] for cirrhosis), for the subgroup of patients with viral hepatitis (n=67/70) but was a poor predictor of disease activity and steatosis levels.

CONCLUSIONS

Supersonic shear imaging is a robust technique for the staging of liver fibrosis. Liver viscosity was found to be correlated with fibrosis but not to steatosis or disease activity.

Rapid decline of liver stiffness following alcohol withdrawal in heavy drinkers

BACKGROUND

Measurement of liver stiffness (LS) using real-time elastography appears as a promising tool to evaluate the severity of chronic liver diseases. Previous studies in patients with alcoholic liver disease have suggested that fibrosis was the only histological parameter to influence LS. To challenge this hypothesis, we have prospectively tested the short-term impact of alcohol withdrawal on LS value.

METHODS

Patients hospitalized for alcohol withdrawal in our Liver and Addiction Unit between 2007 and 2010 had an LS determination at entry (D0) and 7 days after alcohol withdrawal (D7). LS value was given as the median of 10 measurements performed with a FibroScan(®) device. For a given patient, variation of LS was considered as significant when the comparison of the 10 measurements at D0 and at D7 yielded a p-value under 0.05 (Wilcoxon test).

RESULTS

One hundred and thirty-seven patients were included in the study (median alcohol consumption: 150 g/d; hepatitis C: n = 21 [15.6%]). Considering all patients, median LS value decreased from 7.2 to 6.1 kPa between D0 and D7 (p = 0.00001, paired Wilcoxon test). LS decreased significantly in 62 patients (45.3%), and there was a reduction in the estimated stage of fibrosis in 32 (23.3%). LS increased significantly in 16 patients (11.7%). Subgroup analyses revealed that the decrease in LS was still significant in patients with or without hepatitis C infection, and aspartate transaminase level below or above 100 UI/l.

CONCLUSIONS

LS decreases significantly in nearly half of heavy drinkers after only 7 days of abstinence. This result strongly suggests that nonfibrotic lesions (such as the presence of alcoholic hepatitis) may influence LS. From a practical point of view, it also shows that variation of alcohol consumption must be taken into account for the interpretation of LS value.

Epidemiology, management and prognosis of colorectal cancer with lung metastases: a 30-year population-based study

OBJECTIVE

Epidemiological data on synchronous and metachronous lung metastases from colorectal cancer are scarce. The aim of this study was to determine trends in the incidence, treatment and survival in colorectal cancer with lung metastases in the general population.

DESIGN AND PATIENTS

All cases of lung metastases from colorectal cancer registered in the Burgundy digestive cancer registry between 1976 and 2005 were included. Trends in the incidence of synchronous colorectal cancer lung metastases were estimated. A Cox model was used to analyse the risk of developing a metachronous metastasis. Multivariate analyses were performed using a relative survival model with proportional hazard applied to the net survival by interval.

RESULTS

Overall, 11.0% of patients had synchronous lung metastases. The frequency of synchronous lung metastases significantly increased for both sexes over time, with a nearly threefold increase between the periods 1976-1985 and 1996-2005. The overall 5-year cumulative risk of developing metachronous lung metastases was 5.8%. It did not significantly vary with time. Compared to colon cancer, rectal cancers had a higher risk of developing synchronous (OR: 2.80 (1.65-4.76)) and metachronous (OR: 2.63 (1.69-4.08)) lung metastases. Overall, 4.1% of synchronous lung metastases and 14.3% of metachronous lung metastases were resected for cure. The 3-year relative survival was 11.3% for synchronous lung metastases and 13.8% for metachronous lung metastases. It was, respectively, 53.0% and 59.2% after resection for cure. In multivariate analysis, the relative risk of death for the 1996-2005 period was about one fifth of that for the 1976-1985 period.

CONCLUSIONS

The incidence of synchronous lung metastases increased over time, whereas the incidence of metachronous lung metastases remained stable. Lung metastases were more frequent in rectal cancer than in colon cancer. Unless surgical resection is possible, the prognosis for lung metastases remains very poor.