Näherung oder Richtung? Der Theorienstreit der Wahlforschung aus der Sicht politischer Repräsentation

Der Beitrag diskutiert den in der Wahlforschung herrschenden Theorienstreit zwischen Näherung- und Richtungsmodellen aus der Problemperspektive politischer Repräsentation. Aus dieser Perspektive ist die zentrale Frage, wie sich die Parteien zu den ideologischen Positionen ihrer Wähleraggregate platzieren und ob diese Platzierung eher den Erwartungen des Näherung- oder des Richtungsmodells entspricht. Unsere Analysen zeigen, daß keines der beiden konträren Modelle in Reinform funktioniert. Dieselbe Modifikation bewirkt aber, daß beide Modelle mit der Realität konform gehen. Diese Modifikation berücksichtigt die ideologische Distanz zwischen den Wähleraggregaten (Basisdistanz) in ihrer Rolle als wettbewerbsstrukturierendes Element. Die Basisdistanz bietet ein repräsentationstheoretisch adäquates Kriterium (das Lotkriterium), um die Grenzen politischer Repräsentationszonen aus der empirisch jeweils vorgefundenen Konstellation eindeutig bestimmen zu können. -- The article reconsiders the dispute between the proximity and the directional explanation of electoral choice from the perspective of political representation. This perspective raises the question of how parties place themselves towards the ideological positions of their voters and whether this self-placement confirms the proximity or the directional explanation. Our analyses demonstrate that, tested in the original form, neither the proximity nor the directional model comes to terms with reality. But the same modification improves both of the two models in a substantial way. This modification refers to the ideological distance between the major voter aggregates (basis distance) and operationalizes this distance's role in structuring party competition. Thus, we obtain an objective criterion (the perpendicular criterion) to specify zones of representation from an empirical constellation of ideological positions.

Prior surgical intervention and tumor size impact clinical outcome after precision radiotherapy for the treatment of optic nerve sheath meningiomas (ONSM)

<p>Abstract</p> <p>Purpose</p> <p>We analyzed our long-term experience with fractionated stereotactic radiotherapy (FSRT) in patients with meningioma of the optic nerve sheath (ONSM).</p> <p>Patients and Methods</p> <p>Between January 1991 and January 2010, 40 patients with ONSM were treated using FSRT. Of these, 19 patients received radiotherapy as primary treatment, and 21 patients were treated after surgical resection. The median target volume was 9.2 ml, median total dose was 54 Gy in median single fractions of 1,8 Gy.</p> <p>Results</p> <p>Local progression-free survival was 100%. Median survival after FSRT was 60 months (range 4-228 months). In all patients overall toleration of FSRT was very good. Acute toxicity was mild. Prior to RT, 29 patients complained about any kind of visual impairment including visual field deficits, diplopia or amaurosis. Prior surgical resection was identified as a negative prognostic factor for visual outcome, whereas patients with larger tumor volumes demonstrated a higher number of patients with improvement of pre-existing visual deficits.</p> <p>Conclusion</p> <p>Long-term outcome after FSRT for ONSM shows improved vision in patients not treated surgically prior to RT; moreover, the best improvement of visual deficits are observed in patients with larger target volumes. The absence of tumor recurrences supports that FSRT is a strong alternative to surgical resection especially in small tumors without extensive compression of normal tissue structures</p

Monitoring of patients treated with particle therapy using positron-emission-tomography (PET): the MIRANDA study

<p>Abstract</p> <p>Background</p> <p>The purpose of this clinical study is to investigate the clinical feasibility and effectiveness of offline Positron-Emission-Tomography (PET) quality assurance for promoting the accuracy of proton and carbon ion beam therapy.</p> <p>Methods/Design</p> <p>A total of 240 patients will be recruited, evenly sampled among different analysis groups including tumors of the brain, skull base, head and neck region, upper gastrointestinal tract including the liver, lower gastrointestinal tract, prostate and pelvic region. From the comparison of the measured activity with the planned dose and its corresponding simulated activity distribution, conclusions on the delivered treatment will be inferred and, in case of significant deviations, correction strategies will be elaborated.</p> <p>Discussion</p> <p>The investigated patients are expected to benefit from this study, since in case of detected deviations between planned and actual treatment delivery a proper intervention (e.g., correction) could be performed in a subsequent irradiation fraction. In this way, an overall better treatment could be achieved than without any in-vivo verification. Moreover, site-specific patient-population information on the precision of the ion range at HIT might enable improvement of the CT-range calibration curve as well as safe reduction of the treatment margins to promote enhanced treatment plan conformality and dose escalation for full clinical exploitation of the promises of ion beam therapy.</p> <p>Trial Registration</p> <p><a href="http://www.clinicaltrials.gov/ct2/show/NCT01528670">NCT01528670</a></p

Long term results after fractionated stereotactic radiotherapy (FSRT) in patients with craniopharyngioma: maximal tumor control with minimal side effects

Purpose: There are already numerous reports about high local control rates in patients with craniopharyngioma but there are only few studies with follow up times of more than 10 years. This study is an analysis of long term control, tumor response and side effects after fractionated stereotactic radiotherapy (FSRT) for patients with craniopharyngioma. Patients and methods: 55 patients who were treated with FSRT for craniopharyngioma were analyzed. Median age was 37 years (range 6–70 years), among them eight children < 18 years. Radiotherapy (RT) was indicated for progressive disease after neurosurgical resection or postoperatively after repeated resection or partial resection. A median dose of 52.2 Gy (50 – 57.6 Gy) was applied with typical dose per fraction of 1.8 Gy five times per week. The regular follow up examinations comprised in addition to contrast enhanced MRI scans thorough physical examinations and clinical evaluation. Results: During median follow up of 128 months (2 – 276 months) local control rate was 95.3% after 5 years, 92.1% after 10 years and 88.1% after 20 years. Overall survival after 10 years was 83.3% and after 20 years 67.8% whereby none of the deaths were directly attributed to craniopharyngioma. Overall treatment was tolerated well with almost no severe acute or chronic side effects. One patient developed complete anosmia, another one’s initially impaired vision deteriorated further. In 83.6% of the cases with radiological follow up a regression of irradiated tumor residues was monitored, in 7 cases complete response was achieved. 44 patients presented themselves initially with endocrinologic dysfunction none of them showed signs of further deterioration during follow up. No secondary malignancies were observed. Conclusion: Long term results for patients with craniopharyngioma after stereotactic radiotherapy are with respect to low treatment related side effects as well as to local control and overall survival excellent

Pain response of resistance training of the paravertebral musculature under radiotherapy in patients with spinal bone metastases – a randomized trial

BACKGROUND: To compare pain response outcomes for patients with spinal bone metastases treated with resistance training of the spinal musculature versus passive physical therapy during radiotherapy (RT). METHODS: In this randomized trial, 60 consecutive patients were treated from September 2011 until March 2013 within one of the two groups: resistance training (Arm A) or passive physical therapy (Arm B) with thirty patients in each group during RT. The course of pain according to visual analog scale (VAS), concurrent medication, and oral morphine equivalent dose (OMED) were assessed at baseline, three months, and six months after RT. Pain response was determined using International Bone Consensus response definitions. RESULTS: The course of VAS in the intervention group (Arm A) was significantly lower both during and after RT (AUC, p < .001). The use of analgetic medication showed the same result, with significantly fewer analgetics being necessary both during and after RT in arm A (p < .001). In the course of time, the OMED decreased in arm A, but increased in arm B. After 6 month, 72.2% of patients in arm A, and 22.2% in arm B were responders (p = .014). CONCLUSION: Our trial demonstrated that guided isometric resistance training of the paravertebral muscles can improve pain relief over a 6-months period in patients with stable spinal metastases. Importantly, the intervention was able to reduce OMED as well as concomitant pain medication. The trial is registered in Clinical trial identifier NCT 01409720 (http://www.clinicaltrials.gov/) since 2(nd) of August 2011

Impact of delays in initiating postoperative chemoradiation while determining the MGMT promoter-methylation statuses of patients with primary glioblastoma

Background: The benefits of new innovations in glioblastoma therapies should not be curtailed as a result of delays in commencement of radiation therapy, caused by clinical circumstances as well as diagnostic procedures. This study evaluates whether delays in chemo-radiotherapy after surgery, while determining O6-methylguanine-DNA-methyltransferase (MGMT) promoter status, affect the survival rates of patients with glioblastoma (GBM). Methods: Our sample comprised 50 GBM patients in a retrospective analysis of three prospective studies that focused on combined radiotherapy and required MGMT promoter-status testing as inclusion criteria. Results were compared with a reference group of 127 favourable GBM cases (Karnofsky performance-status scale ≥ 70), in which the patients underwent standard postoperative chemo-radiotherapy with temozolomide. Survival time was calculated using the Kaplan-Meier method, and a multivariate analysis of the delays between surgical and radiotherapy procedures was performed using the Cox regression model. Results: The study group’s median overall survival time was 16.2 months (with a range of 2 to 56 months), versus the reference group’s survival time of 18.2 months (with a range of 1 to 92 months) (p = 0.64). The delay between surgery and radiotherapy was increased by 8 days in the study patients (p < 0.001), with a median delay of 35 days (range: 18–49 days) corresponding to the typical 27-day delay (range: 5–98 days) for those in the reference group. Univariate and multivariate analyses did not show any negative association between survival time and delaying radiation therapy to determine MGMT-promoter status; commencement of radiation therapy sooner than 24 days after surgery was the threshold for significantly decreased overall survival (p = 0.01) and progression-free (p = 0.03) survival. Conclusion: Delaying postoperative chemoradiation for GBM patients—carried out in order to determine MGMT-promoter status—did not have a negative impact on survival time. Indeed, the data of the present study shows that initiating radiation therapy sooner than 24 days after surgery has a negative impact on progression and survival

Biochemical markers of bone turnover in patients with spinal metastases after resistance training under radiotherapy – a randomized trial

Background: To compare the effects of resistance training versus passive physical therapy on bone turnover markers (BTM) in the metastatic bone during radiation therapy (RT) in patients with spinal bone metastases. Secondly, to evaluate an association of BTM to local response, skeletal-related events (SRE), and number of metastases. Methods: In this randomized trial, 60 patients were allocated from September 2011 to March 2013 into one of the two arms: resistance training (Arm A) or passive physical therapy (Arm B) with thirty patients in each arm during RT. Biochemical markers such as pyridinoline (PYD), desoxy-pyridinoline (DPD), bone alkaline phosphatase (BAP), total amino-terminal propeptide of type I collagen (PINP), beta-isomer of carboxy-terminal telopeptide of type I collagen (CTX-I), and cross-linked N-telopeptide of type I collagen (NTX) were analyzed at baseline, and three months after RT. Results: Mean change values of PYD and CTX-I were significantly lower at 3 months after RT (p = 0.035 and p = 0.043) in Arm A. Importantly, all markers decreased in both arms, except of PYD and CTX-I in arm B, although significance was not reached for some biomarkers. In arm A, the local response was significantly higher (p = 0.003) and PINP could be identified as a predictor for survivors (OR 0.968, 95%CI 0.938–0.999, p = 0.043). BAP (OR 0.974, 95%CI 0.950–0.998, p = 0.034) and PINP (OR 1.025, 95%CI 1.001–1.049, p = 0.044) were related with an avoidance of SRE. Conclusions: In this group of patients with spinal bone metastases, we were able to show that patients with guided resistance training of the paravertebral muscles can influence BTM. PYD and CTX-I decreased significantly in arm A. PINP can be considered as a complementary tool for prediction of local response, and PINP as well as BAP for avoidance of SRE. Trial registration: Clinical trial identifier NCT 01409720. August 2, 2011

Outcome and prognostic factors of multimodal therapy for pulmonary large-cell neuroendocrine carcinomas

Background: There is controversy whether patients diagnosed with large-cell neuroendocrine carcinoma (LCNEC) should be treated according to protocols for non-small cell lung cancers (NSCLC) or small cell lung cancers (SCLC), especially with regard to the administration of prophylactic cranial irradiation (PCI). This study was set up to determine the incidence of brain metastases and to investigate the outcome following multimodal treatment in 70 patients with LCNEC. Methods: Seventy patients with histologically confirmed LCNEC were treated at the University Hospital of Heidelberg between 2001 and 2014. Data were collected retrospectively. Al most all patients received thoracic surgery as initial treatment (94 %). Chemotherapy was administered in 32 patients as part of the initial treatment. Fourteen patients were treated with adjuvant or definitive thoracic radiotherapy according to NSCLC protocols. Cranial radiotherapy due to brain metastases, mostly given as whole brain radiotherapy (WBRT), was received by fourteen patients. Statistical analysis was performed using the long-rank test and the Kaplan–Meier method. Results: Without PCI, the detected rate for brain metastases was 25 % after a median follow-up time of 23.4 months, which is comparable to NSCLC patients in general. Overall (OS), local (LPFS), brain metastases-free survival (BMFS) and extracranial distant progression-free survival (eDPFS) was 43, 50, 63 and 50 % at 5 years, respectively. Patients with incomplete resection showed a survival benefit from adjuvant radiotherapy. The administration of adjuvant chemotherapy improved the general worse prognosis in higher pathologic stages. Conclusion: In LCNEC patients, the administration of radiotherapy according to NSCLC guidelines appears reasonable and contributes to acceptable results of multimodal treatment regimes. The low incidence of spontaneous brain metastases questions a possible role of PCI

Late normal tissue response in the rat spinal cord after carbon ion irradiation

Background: The present work summarizes the research activities on radiation-induced late effects in the rat spinal cord carried out within the “clinical research group ion beam therapy” funded by the German Research Foundation (DFG, KFO 214). Methods and materials: Dose–response curves for the endpoint radiation-induced myelopathy were determined at 6 different positions (LET 16–99 keV/μm) within a 6 cm spread-out Bragg peak using either 1, 2 or 6 fractions of carbon ions. Based on the tolerance dose TD50 of carbon ions and photons, the relative biological effectiveness (RBE) was determined and compared with predictions of the local effect model (LEM I and IV). Within a longitudinal magnetic resonance imaging (MRI)-based study the temporal development of radiation-induced changes in the spinal cord was characterized. To test the protective potential of the ACE (angiotensin converting enzyme)-inhibitor ramipril™, an additional dose–response experiment was performed. Results: The RBE-values increased with LET and the increase was found to be larger for smaller fractional doses. Benchmarking the RBE-values as predicted by LEM I and LEM IV with the measured data revealed that LEM IV is more accurate in the high-LET, while LEM I is more accurate in the low-LET region. Characterization of the temporal development of radiation-induced changes with MRI demonstrated a shorter latency time for carbon ions, reflected on the histological level by an increased vessel perforation after carbon ion as compared to photon irradiations. For the ACE-inhibitor ramipril™, a mitigative rather than protective effect was found. Conclusions: This comprehensive study established a large and consistent RBE data base for late effects in the rat spinal cord after carbon ion irradiation which will be further extended in ongoing studies. Using MRI, an extensive characterization of the temporal development of radiation-induced alterations was obtained. The reduced latency time for carbon ions is expected to originate from a dynamic interaction of various complex pathological processes. A dominant observation after carbon ion irradiation was an increase in vessel perforation preferentially in the white matter. To enable a targeted pharmacological intervention more details of the molecular pathways, responsible for the development of radiation-induced myelopathy are required