Cure for ductal adenocarcinoma of the pancreas is restricted to resectable tumors, but survival after surgery is still poor. Despite apparently curative resection, these cancers rapidly recur. Thus, the present pathologic examination should be enriched by sensitive methods to detect minimal residual disease. In a prospective setting we studied the frequency of minimal residual disease after curative resection by routine histopathology, immunohistology, and polymerase chain reaction (PCR) for mutated K-ras. Furthermore, the prognostic implication of detecting of MRD was determined. Prospectively, tumor tissue and corresponding paraaortic lymph nodes were obtained from 78 patients, who underwent surgery for pancreatic head tumors between 1999 and 2001. Sixty-nine of 78 cases were diagnosed for ductal adenocarcinoma (study group), whereas nine cases were diagnosed for benign pancreatic tumors (control group). Paraaortic lymph nodes were examined in step sections by routine histopathology (hematoxylin and eosin) and immunohistology using a pan-cytokeratin antibody. DNA of the primary tumor and corresponding paraaortic lymph nodes were analyzed by PCR-based assays with respect to mutated K-ras in codon 12. The recurrence-free survival and overall survival were correlated with the results of the latter methods. In 3 of 69 patients tumor cells were detected in paraaortic lymph nodes by routine histopathology and in 5 of 69 patients by immunohistology. K-ras mutations were detected in 42 of 69 ductal adenocarcinomas (61%), whereas 12 (17%) were positive in paraaortic lymph nodes. All of the latter patients had recurrence after surgery and a significant poorer survival than those without mutated K-ras. Furthermore, paraaortic lymph nodes diagnosed for K-ras mutation were independent prognostic markers in multivariate analysis. In the control group K-ras mutations were detected in one adenoma of Vater's papilla but not in paraaortic lymph nodes. Tumor cell DNA can be detected more sensitively by the described PCR method than with hematoxylin and eosin or immunohistologic staining, leading to a higher sensitivity for detection of micrometastases. The described PCR method clearly determines subgroups of patients after curative resection with early recurrence and poor survival and could therefore enrich the pathologic examination.
"Previous research has demonstrated a relationship between K-ras mutation and the presence of lymph node metastases. Niedergethmann et al. have reported that para-aortic lymph nodes diagnosed for K-ras mutation were independent pancreatic cancer prognostic markers in multivariate analysis . All of the patients with the K-ras mutation in lymph nodes had recurrence after surgery and a significantly poorer survival than those without mutated K-ras. "
[Show abstract][Hide abstract] ABSTRACT: Background:
More clinically meaningful diagnostic tests are needed in pancreatic cancer (PC). K-ras mutations are the most frequently acquired genetic alteration.
Original research articles involving the diagnostic accuracy of K-ras mutation detection in PC were selected. Data were presented as forest plots and summary receiver operating characteristic (SROC) curve analysis was used to summarize the overall test performance.
We assessed 19 studies from 16 published articles. The reports were divided into three groups according to the process used to obtain the test material. The summary estimates for detecting K-ras status using an invasive method (fine needle aspiration (FNA), endoscopic retrograde cholangiopancreatography (ERCP), or surgery) were better than cytology: the pooled sensitivity was 77% (95% confidence interval (CI): 74-80%) versus 54% (95% CI: 47-61%); specificity was 88% (95% CI: 85-91%) versus 91% (95% CI: 83-96%); and diagnostic odds ratio (DOR) was 20.26 (11.40-36.03) versus 7.52 (95% CI: 2.80-20.18), respectively. When two procedures were combined, the diagnostic accuracy was markedly improved.
The analysis of K-ras mutations in pancreatic tissue has a promising diagnostic significance in PC. Further valuable studies are needed.
"If this is true in humans, it may be the route through which activated carcinogens reach the head of pancreas (carcinogen containing bile refluxing into the pancreatic duct). This theory is attractive given that the pancreatic head is the most frequent site for adenocarcinoma   . A study in rhesus monkeys (n = 4), however, found that biliary excretion of the NNK metabolites was significantly less than predicted from rat experiments. "
[Show abstract][Hide abstract] ABSTRACT: The extremely poor outcome from pancreas cancer is well known. However, its aetiology less well appreciated, and the molecular mechanisms underlying this are poorly understood. Tobacco usage is one of the strongest risk factors for this disease, and this is a completely avoidable hazard. In addition, there are well described hereditary diseases which predispose, and familial pancreas cancer. We have sought here to summarise the role of tobacco-derived carcinogens and the mode of their tumorigenic action on the pancreas. There is compelling evidence from animal and human studies (laboratory including cell line studies and epidemiologic) that tobacco derived carcinogens cause pancreas cancer. However, the manner in which they do so is not entirely apparent. There is also compelling evidence that synergism with genetic and other life-style factors-like diet obesity-results in a multifactorial causation of the disease. Ascertaining the role of tobacco carcinogens in the development of this cancer and their interaction with other risk factors will enable novel therapeutic and preventative strategies to improve outcome from this appalling malignancy.
[Show abstract][Hide abstract] ABSTRACT: Background and purpose
Target volume definitions for radiotherapy in pancreatic ductal adenocarcinoma (PDAC) vary substantially. Some groups aim to treat the primary tumor only, whereas others include elective lymph nodes (eLNs). eLNs close to the primary tumor are often included unintentionally within the treatment volume, depending on the respective treatment philosophies. We aimed to measure the percentages of anatomical coverage of eLNs by comparing four different contouring guidelines.
Patients and methods
Planning target volumes (PTVs) were contoured using planning computed tomography (CT) scans of 11 patients with PDAC based on the Oxford, RTOG (Radiation Therapy Oncology Group), Michigan, and SCALOP (Selective Chemoradiation in Advanced Localised Pancreatic Cancer trial) guidelines. Clinical target volumes (CTVs) included the peripancreatic, para-aortic, paracaval, celiac trunk, superior mesenteric, and portal vein lymph node areas. Volumetric comparisons of the coverage of all eLN regions were conducted to illustrate the differences between the four contouring strategies.
The PTV sizes of the RTOG and Oxford guidelines were comparable. The SCALOP and Michigan PTV sizes were similar to each other and significantly smaller than the RTOG and Oxford PTVs. A large variability of eLN coverage was found for the various subregions according to the respective contouring strategies.
This is the first study to directly compare the percentage of anatomical coverage of eLNs according to four PTVs in the same patient cohort. Potential practical consequences are discussed in detail.
Strahlentherapie und Onkologie 05/2013; 189(5). DOI:10.1007/s00066-013-0332-3 · 2.91 Impact Factor
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