Andreas W. Berger

Detection of Hot-Spot Mutations in Circulating Cell-Free DNA From Patients With Intraductal Papillary Mucinous Neoplasms of the Pancreas

Intraductal papillary mucinous neoplasms (IPMNs) are the most frequent cystic pancreatic tumors. Little is known about their molecular alterations, but mutations in GNAS have been reported to promote IPMN formation. A tumor-derived fraction of circulating cell-free DNA (cfDNA), isolated from blood samples, contains many of the same mutations as the primary tumor, and could be a tool for noninvasive disease monitoring. We found that the total amount of cfDNA can discriminate between individuals without pancreatic lesions (controls) and patients with Fukuoka-negative branch-duct IPMN or pancreatic cancer. Furthermore, we detected GNAS mutations in cfDNA fromxa0patients with IPMN, but not in patients with serous cystadenoma or controls. Analyses of cfDNA might therefore be used in the diagnosis of patients with IPMN or in monitoring disease progression.

DocOx (AIO-PK0106): a phase II trial of docetaxel and oxaliplatin as a second line systemic therapy in patients with advanced pancreatic ductal adenocarcinoma

BackgroundThe current study was conducted to examine the activity of a docetaxel/oxaliplatin (DocOx) combination as second line treatment for advanced pancreatic ductal adenocarcinoma (Trial registration: NCT00690300. Registered June 2, 2008)MethodsDocOx is a prospective, multi-center, single arm, phase II trial using docetaxel (75xa0mg/m2, 60xa0min, d 1) and oxaliplatin (80xa0mg/m2, 120xa0min, d 2) in 21-day cycles. The treatment period was scheduled for up to 8xa0cycles. Primary endpoint was tumor response according to RECIST 1.0. Secondary endpoints were progression free survival, overall survival, safety/toxicity, quality of life and clinical benefit.ResultsData represent the intention to treat analysis of 44 patients with chemorefractory pancreatic cancer enrolled between 2008 and 2012 at five institutions in Germany. The primary endpoint of tumor response was achieved in 15.9xa0% of the patients (7 partial remissions, no complete remission), with a disease control rate of 48xa0% after the first two treatment cycles. Median progression free survival (PFS) was 1.82xa0months (CI 95xa0% 1.5–3.96xa0months) and median overall survival (OS) was 10.1xa0months (CI 95xa0% 5.1–14.1xa0months).ConclusionsThis single-arm trial demonstrates that the combination of docetaxel and oxaliplatin yields promising results for the treatment of advanced pancreatic ductal adenocarcinoma patients. Selected patients had particular benefit from this treatment as indicated by long PFS and OS times. Even after 8xa0cycles of treatment with DocOx a partial response was observed in 2 patients and stable disease was observed in another 6 patients. The data obtained with the DocOx protocol compare well with other second line protocols such as OFF (oxaliplatin, 5-FU, leucovorin). The DocOx regimen could be an interesting option for patients who received gemcitabine as first line treatment for metastatic pancreatic cancer.

Treatment monitoring in metastatic colorectal cancer patients by quantification and KRAS genotyping of circulating cell-free DNA.

Treatment of metastatic colorectal cancer (CRC) has continuously improved over the last decade. However, disease monitoring remains underdeveloped and mostly dependent on imaging e.g. RECIST 1.1 criteria. The genetic landscape of individual cancers and subsequently occurring treatment-induced evolution remain neglected in current surveillance strategies. Novel biomarkers demand minimally invasive and repetitive tracking of the cancer mutagenome for therapy stratification and to make prognostic predictions. Carcinoembryonic antigen (CEA), a routinely used tumor marker for CRC, does not meet these goals and thus prevents its use as a reliable monitoring tool. A tumor-derived fraction of circulating cell-free DNA (cfDNA), isolated from blood samples, may bypass the limitations of currently available biomarkers and could be a tool for noninvasive disease monitoring. Here, total cfDNA levels differentiated a cohort of metastatic CRC patients from healthy controls. Furthermore, we correlated cfDNA during chemotherapy of 27 stage IV patients with clinical parameters to establish its prognostic and predictive value. Indeed, cfDNA levels in chemotherapy naive patients correlate with the tumor burden and CEA values at diagnosis and increase upon disease progression during 1st and 2nd line treatment. Moreover, we confirm the possibility of cfDNA-based genotyping of KRAS to early detect the emergence of resistance during chemotherapy. These data indicate that repetitive quantitative and mutational analysis of cfDNA might complement current treatment standards but may have also limited value in some patients.

Targeted deep sequencing of circulating tumor DNA in metastatic pancreatic cancer

Purpose Precision medicine in pancreatic ductal adenocarcinoma (PDAC) could be substantially supported by tools that allow to establish and monitor the molecular setup of the tumor. In particular, noninvasive approaches are desirable, but not validated. Characterization of circulating tumor DNA (ctDNA) may help to achieve this goal. Experimental Design Blood samples from patients with metastatic PDAC prior to and during palliative treatment were collected. ctDNA and corresponding tumor tissue were analyzed by targeted next generation sequencing and droplet digital PCR for the 7 most frequently mutated genes in PDAC (TP53, SMAD4, CDKN2A, KRAS, APC, ATM, and FBXW7). Findings were correlated with clinical and imaging data. Results A total of 20 patients (therapy naïve n = 11; pretreated n = 9) were included. All therapy naïve patients (n = 11/11) presented with detectable ctDNA at baseline. In pretreated patients, 3/7 (prior to 2nd line treatment) and 2/2 (prior to 3rd line chemotherapy) had detectable ctDNA. The combined mutational allele frequency (CMAF) of KRAS and TP53 was chosen to reflect the amount of ctDNA. The median CMAF level significantly decreased during treatment (P = 0.0027) and increased at progression (P = 0.0104). CA19-9 analyses did not show significant differences. In treatment naïve patients, the CMAF levels during therapy significantly correlated with progression-free survival (Spearman, r = −0.8609, P = 0.0013). Conclusions Monitoring of ctDNA and its changes during treatment may enable to adapt therapeutic strategies to the specific molecular changes present at a certain time during treatment of mPDAC.

Surveillance after resection of pancreatic ductal adenocarcinoma with curative intent – a multicenter survey in Germany and review of the literature

Backgroundu2002Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers with high risk of relapse even after curative-intended resection. There are no evidence-based recommendations for surveillance in actual guidelines. Given this situation and as a basis for prospective studies, we wanted to determine the current practice of surveillance after pancreatic cancer resection in German institutions. Methodsu2002A web-based questionnaire was sent in 2015 to 300 German institutions (hospitals, outpatient clinics, and private practices) experienced in the care of patients with PDAC. The questionnaire comprised 23 items including the respective institution, the level of care, the annual case load of pancreatic cancer surgery, the surveillance algorithms used, and the most frequently used means for surveillance as well as their evaluation by the users with respect to the effectiveness of these means. Additionally, we perform a review of the literature. Resultsu2002The final analysis comprised 161 questionnaires (response rate 53.7u200a%). Mainly high-volume centers (82.5u200a% with >u200a300 hospital beds) participated. In 46.6u200a% of centers, more than 80u200a% of patients received adjuvant chemotherapy after surgery. Between 60u200a-u200a80u200a% of these patients completed the recommended 6 months of adjuvant treatment, and 47u200a% of the patients received the whole treatment (surgery, adjuvant therapy) and surveillance in the same center. Upon completion of adjuvant treatment, 96u200a% of centers survey their patients, and 82u200a% of these centers already employ diagnostic means during the course of adjuvant chemotherapy. The most commonly used diagnostic means were taking patient history, conducting physical examination, performing laboratory tests including CA19u200a-u200a9, and imaging. Of those employed, CA19u200a-u200a9 and imaging followed by patient history were considered the most efficient to detect disease relapse by the centers. Half of the institutions perform surveillance for 5 years after surgery. Conclusionu2002This is the first systematic analysis of self-reported surveillance strategies used in Germany after resection of PDAC with curative intent. Surveillance after resection of PDAC with curative intent is common in Germany. Alterations of CA19u200a-u200a9 levels as well as imaging and taking patient history are considered the most efficient means to detect relapse of disease by the physicians participating in our survey.

Genetic Biopsy for Prediction of Surveillance Intervals after Endoscopic Resection of Colonic Polyps: Results of the GENESIS Study

Background and objective Current surveillance strategies for colorectal cancer following polypectomy are determined by endoscopic and histopathological factors. Such a distinction has been challenged. The present study was designed to identify molecular parameters in colonic polyps potentially defining new sub-groups at risk. Methods One hundred patients were enrolled in this multicentre study. Polyps biopsies underwent formalin-free processing (PAXgene, PreAnalytiX) and targeted next generation sequencing (38 genes (QIAGEN), NextSeq 500 platform (Illumina)). Genetic and histopathological analyses were done blinded to other data. Results In 100 patients, 224 polyps were removed. Significant associations of genetic alterations with endoscopic or histological polyp characteristics were observed for BRAF, KRAS, TCF7L2, FBXW7 and CTNNB1 mutations. Multivariate analysis revealed that polypsu2009≥u200910u2009mm have a significant higher relative risk for harbouring oncogene mutations (relative risk 3.467 (1.742–6.933)). Adenomas and right-sided polyps are independent risk factors for CTNNB1 mutations (relative risk 18.559 (2.371–145.245) and 12.987 (1.637–100.00)). Conclusions Assessment of the mutational landscape of polyps can be integrated in the workflow of current colonoscopy practice. There are distinct genetic patterns related to polyp size and location. These results suffice to optimise individual risk calculation and may help to better define surveillance intervals.

Algorithm guided outlining of 105 pancreatic cancer liver metastases in Ultrasound

Manual segmentation of hepatic metastases in ultrasound images acquired from patients suffering from pancreatic cancer is common practice. Semiautomatic measurements promising assistance in this process are often assessed using a small number of lesions performed by examiners who already know the algorithm. In this work, we present the application of an algorithm for the segmentation of liver metastases due to pancreatic cancer using a set of 105 different images of metastases. The algorithm and the two examiners had never assessed the images before. The examiners first performed a manual segmentation and, after five weeks, a semiautomatic segmentation using the algorithm. They were satisfied in up to 90% of the cases with the semiautomatic segmentation results. Using the algorithm was significantly faster and resulted in a median Dice similarity score of over 80%. Estimation of the inter-operator variability by using the intra class correlation coefficient was good with 0.8. In conclusion, the algorithm facilitates fast and accurate segmentation of liver metastases, comparable to the current gold standard of manual segmentation.

The occurrence of mutant KRAS clones in the blood of RAS wild type colorectal cancer patients: Impact of response or failure under anti-EGFR therapy.

600 Background: Colorectal cancer (CRC) is characterized by a high level of genetic heterogeneity. In addition, changes in the genetic profile induced by chemotherapy affect treatment results. Acquired resistance of tumors is defined as a result of clonal evolution and clonal selection under systemic chemotherapy. Repeated tumor tissue biopsies are difficult to obtain and cannot be easily used for dynamic monitoring of therapy response or failure due to marked tumor heterogeneity. Promising data for circulating cell-free tumor DNA (ctDNA) as a tool for studying tumor evolution were recently published. Methods: In this study we analyzed ctDNA from patients with metastatic CRC during treatment with anti-epidermal growth factor receptor (EGFR) antibodies (cetuximab/panitumumab). By droplet digital PCR we performed genotyping of CRC tissue and tracking of clonal evolution of the most frequent KRAS mutations (G12A, G12C, G12D, G12R, G12S, G12V, G13C, G13D, Q61R, A146T and A59T) in plasma ctDNA. Results: In ini...