Einfluss einer CT-basierten bildgebenden Diagnostik auf das Management und den Verlauf nicht-funktioneller neuroendokriner Pankreastumore

Non-functioning neuroendocrine pancreatic tumors (nf-NPT) are a rare tumor entity of potentially malignant character. As the symptomatology usually appears very late and is non-specific, these tumors are often diagnosed at a locally advanced or already metastasized stage. However, the prognosis depends, among other things, on early detection of the tumor and a curative surgical intervention. Imaging procedures play a very significant role in the diagnosis. Among these procedures, abdominal sonography and abdominal CT scans, as the most frequently used and easily available techniques, play an exceptionally important role and are considered to be the primary diagnostic tool. As a result of technical improvements and the fact that CT scan is being performed increasingly frequent, an earlier detection of nf-NPT, including incidental tumors, is to be expected. Tumors should not only be detected earlier but also smaller of size. The aim of this study was to assess the impact of improved imaging on these features in a tertiary referral centre within a 20-year follow-up. Forty-one patients with nf-NPT who underwent tumor resection were retrospectively divided in two groups according to the date of the initial diagnosis, group 1: 1989-1999 vs. group 2: 2000-2009. It could not be shown that the continuously developing CT technology had influence on the initial tumor detection. In group 1, the mean reported CT-determined tumor size was 56 vs. 54 mm in group 2. However there were indications of an increased quality with regard to the morphological images achieved with the CT scan, enabling a more precise measurement of tumor size, and better assessment of operability and resectability. The detection of synchronous metastases did also not differ significantly (61% in group 1 vs. 57 % group 2); only the spread of the metastases was different. More recently (2000-2009) distant metastases were predominantly shown, while in the earlier period lymph node metastases were more often detected. The increase in distant metastases is an indication of the change in the therapeutic regimen, with a tendency towards aggressive radical surgery, also in a metastasized stage. Earlier detection of sporadic nf-NPT cannot be expected in the future either, as this is a very rare disease with a lack of symptomatology in the early stage. Nevertheless this is the stage with the most favourable prognosis. However, as has already been argued, the prognosis can be improved by radical surgical therapy which comprises, in addition to the removal of the tumor, the resection of synchronous and metachronous metastases if technically and oncologically possible. The basic prerequisite for appropriate and early surgical treatment of metachronous metastases is regular post-operative care. In recent years metachronous metastases appeared and have been detected significantly earlier. Metachronous metastases were recorded in 39 % in group 1 with a mean interval from initial resection to diagnosis of the metastatic disease of 61 month vs. 43% in group 2 with a mean interval of 14 months. According to the change of therapeutic recommendations the cumulative 5-year-survival rate in group 2 was lower with a high rate of initial distant metastases to determine (77% in group 1 vs. 66% in group 2). On the basis of current study results, which show that a radical operation leads to an improved prognosis even with hepatic metastases, this group of patients is more often subjected to potentially curative surgery. Close surveillance including regular imaging is essential for these patients in order to enable prompt introduction of further treatment measures, should metastasis or tumor recurrence be identified. Therapy of this rare tumor entity should be carried out exclusively in medical centres with an appropriate experience and an interdisciplinary approach. In order to proof the results and conclusions of this thesis, which were based on a limited number of patients, a multi-centre study should be conducted involving a large number of cases.