Diagnostische Wertigkeit von MRT- und CT-Untersuchungen bei Pankreastumoren

Every year in Germany there are more than 450 000 people who are diagnosed with oncological diseases. Approximately 2,5% of all tumors have their origin in the adenozytes of the pancreas. The adenocarcinoma is the leading entity with about 95%. Due to its high mortality rate the adenocarcinoma of the exocrine pancreas stands at fourth position of cancer related deaths. Proper screening methods for the asymptomatic population are not available yet. Radiological resectability assessment is of great importance because many obviously unresectable cases can be identified preoperatively. Neuroendocrine tumors of the pancreas are very rare with a incidence of 0,01 to 0,04 per mill. The purpose for imaging procedures is to localize functional endocrine tumors because of their small size and to characterize non functional tumors due to their expanding growth. This study retrospectively evaluates the diagnostic validity of magnetic resonance imaging and computed tomography by comparing them with the results of the histopathlogical examination. 105 patients who were operated between 2005 and 2011 at the Department of Visceral, Thoracic and Vascular Surgery at the Universitiy Hospital Marburg, had been included in this study. On the basis of the preoperatively radiological evaluation regarding the following four criteria such as distant metastasis, lymphnodes, vascular involvement and resectability assessment, we reviewed the diagnostic validity of both imaging procedures. The study shows comparable results for MRI and CT in evaluating the resectability of adenocarcinoma of the pancreas. In neuroendocrine tumors both MRI and CT are able to evaluate resectability with high sensitivity. In identifying distant metastases in adenocarcinoma, MRI achieves higher diagnostic validity. Whereas in neuroendocrine tumors both imaging procedures show “moderate but usually important” diagnostic evidence concerning distant metastases. The preoperative lymph node staging shows the lowest sensitivities for both MRI and CT compared with the remaining criteria. For the evaluation of vascular involvement in adenocarcinoma CT shows “large, often conclusive” evidence compared to “small, sometimes important” evidence of the MRI. In neuroendocrine tumors both MRI and CT are capable to preoperatively evaluate peripancreatic vascular involvement, although MRI achieves slightly higher sensitivity and specificity. Based on the evaluation of the questionnaire results we could determine the survival times after initial diagnosis of 79% of all patients. Therefore it was possible to analyze postoperative survival in relation to the four radiological diagnostic criteria. It became evident that for both types of tumor R0-resection correlated with significant longer survival than R1-/R2- resection. Patients with distant metastases in adenocarcinoma had a significantly worse prognosis than those without distant metastasis. Furthermore, resection of distant metastases in adenocarcinoma goes along with longer survival than operations without metastasis resection. Despite the presence of distant metastases survival rates > 5 years in neuroendocrine tumors are possible. Lymph node metastases have no significant impact on the survival rate of patients with adenocarcinoma of the pancreas. Although lymph node metastases are present long term survival in neuroendocrine tumors can be achieved. Vascular involvement shortens the survival of patients with adenocarcinoma but there was no significant difference. In neuroendocrine tumors vascular involvement had no influence on postoperative survival. Despite intensive research and new therapeutic approaches the clinical success lags behind the stated expectations concerning adenocarcinoma of the pancreas. At present 25% of operations performed had to be terminated because of inoperable vascular involvement or metastatic disease. Precise radiological diagnostic is a subject of major importance. The technical progress of imaging procedures will lead to a better differentiation between involved structures. Further studies will have to decide if or to which extent signs of unresectability will change.