Biomedical subjects

Michael Flentje

Publications and source records attributed to Michael Flentje.

At least 55 records · Page 3Linked to original sources

PubMed2004

Positional variability of a tandem applicator system in HDR brachytherapy for primary treatment of cervix cancer. Analysis of the anatomic pelvic position and comparison of the applicator positions during five insertions.

PURPOSE: Evaluation of the inter- and intraindividual applicator variability of multiple high-dose-rate (HDR) brachytherapy applications for primary treatment of cancer of the uterine cervix. MATERIAL AND METHODS: Retrospective analysis of 460 pairs of orthogonal X-ray films for conventional treatment in 92 patients with five intrauterine applications using an HDR tandem applicator. Measurement of the position of the applicator origin relative to a bony reference system in three dimensions. Evaluation of the differences of the applicator position in all 460 applications (interindividual variability), of the five applications in a single patient (intraindividual variability) and of the intraindividual variability relative to the applicator position at the first application. RESULTS: The position of the applicator origin in the pelvis ranged from 23 mm cranial and 55 mm caudal to the top of femoral heads, 23 mm right and 27 mm left to the pelvic midline, and 6-53 mm dorsal to the mid of the femoral heads. Standard deviation (SD) of interindividual applicator variability was 12.9 mm (minimum/maximum -55/+23 mm, mean -13.6 mm) in longitudinal, 5.1 mm (-27/+23 mm, mean 1.6 mm) in lateral, and 7.6 mm (6/53 mm, mean 26 mm) in anterior-posterior [AP] direction. SD of intraindividual variability was 5.5 mm (-21/+23 mm, mean 0 mm) in longitudinal, 2.5 mm (-17/+19 mm, mean 0 mm) in lateral, and 4.2 mm (-15/+18 mm, mean 0 mm) in AP direction compared to intraindividual variability relative to the first insertion with an SD of 8.9 mm (-23/+36 mm, mean 2.8 mm) in longitudinal, 4.0 mm (-11/+23 mm, mean 0 mm) in lateral, and 6.8 mm (-27/+17 mm, mean -0.8 mm) in AP direction. CONCLUSION: Intraindividual applicator variability is significantly smaller than interindividual variability. Applicator-related procedures such as midline shielding or dose matching of tele- and brachytherapy should be performed with information on at least one individual applicator position.

Adenocarcinoma↗

PubMed2004

Radiation response in vitro of fibroblasts from a fanconi anemia patient with marked clinical radiosensitivity.

BACKGROUND: . Fanconi anemia (FA) is an autosomal recessive chromosome instability disorder characterized by progressive pancytopenia and cancer susceptibility. The risks of radiation therapy in FA patients who have cancer remain to be investigated. Recently, Marcou et al. (2001) reported a case of severe clinical radiosensitivity in a female FA patient with a tonsillar squamous cell carcinoma treated by radiotherapy. By contrast, her in vitro irradiated skin fibroblasts revealed nearly normal radiosensitivity as determined by the colony survival assay. MATERIAL AND METHODS: . In view of this discrepancy, the radiation response of this particular FA fibroblast strain (designated 425BR) was further analyzed in the present study by means of the alkaline single-cell gel electrophoresis (Comet) assay, and also by the cytochalasin-blocked micronuclei (MN) test. In addition, the expression levels of DNA repair proteins, hMre11, Rad50, and Rad51, were investigated using Western blot and foci immunofluorescence staining. RESULTS: . The Comet assay revealed that the initial DNA fragmentation in irradiated FA cells was two times higher and the DNA rejoining process was three times slower than that in control (1BR3) fibroblasts. Moreover, although the baseline level of MNs was lower in FA cells than in controls, the FA fibroblasts were more prone (about two times) to MN production than control cells when irradiated with 2-4 Gy. Western blot analysis of the DNA repair proteins (hMre11, Rad50, and Rad51) did not reveal any abnormalities in protein expression levels or their migration patterns in the fibroblasts derived from an FA patient either before or after irradiation. At the same time, in vitro irradiated cells from the FA patient exhibited a significantly reduced number of nuclei with focally concentrated DNA repair Rad51 protein than in control cells. CONCLUSION: . The increased DNA damage and MN induction in irradiated FA fibroblasts, and the reduction of the formation of DNA repair foci containing Rad51 suggest a possible link to the profound clinical radiosensitivity reported earlier for this FA patient. The findings on this particular FA cell strain presented in the study point toward the difficulties involved in the prediction of the radiation response of cell lines and tumors based solely on the colony survival test.

Adult↗

PubMed2004

Influence of calculation algorithm on dose distribution in irradiation of non-small cell lung cancer (NSCLC) collapsed cone versus pencil beam.

PURPOSE: . The influence of two different calculation algorithms ("pencil beam" [PB] versus "collapsed cone" [CC]) on dose distribution, as well as the dose-volume histograms (DVHs) of the planning target volume (PTV) and the organs at risk was analyzed for irradiation of lung cancer. MATERIAL AND METHODS: . Between 10/2001 and 02/2002 three-dimensional treatment planning was done in ten patients with lung cancer (Helax, TMS((R)), V.6.01). The PTV, the ipsilateral lung (IL) and the contralateral lung (CL) were defined in each axial CT slice (slice thickness 1 cm). Dose distributions for three-dimensional multiple-field technique were calculated using a PB and a CC algorithm, respectively. Normalization was in accordance with ICRU 50. The DVHs were analyzed relating the minimum, maximum, median and mean dose to the volumes of interest (VOI). RESULTS: . Median PTV amounted to 774 cm(3). Minimum dose within the PTV was 67.4% for CC and 75.6% for PB algorithm (p = 0.04). Using the CC algorithm, only 76.5% of the PTV was included by the 95% isodose, whereas 90.1% was included when the PB algorithm (p = 0.01) was used. Median volume of IL amounted to 1 953 cm(3). Mean dose to IL was 43.0% for CC and 44.0% for PB algorithm (p = 0.02). Median volume of IL within the 80% isodose was 19.6% for CC and 24.1% for PB algorithm (p < 0.01). Median volume of CL amounted to 1 847 cm(3). Mean dose to CL was 17.4% for CC and 18.1% for PB algorithm (p < 0.01). Volume of CL within the 80% isodose was 3.3% for CC and 4.1% for PB algorithm (p = 0.03). CONCLUSION: . The CC and PB calculation algorithms result in different dose distributions in case of lung tumors. Particularly the minimum dose to the PTV, which may be relevant for tumor control, is significantly lower for CC. Since it is generally accepted that the CC algorithm describes secondary particle transport more exactly than PB models, the use of the latter should be critically evaluated in the treatment planning of lung cancer.

Algorithms↗

PubMed2004

Impact of hypoxia and the metabolic microenvironment on radiotherapy of solid tumors. Introduction of a multi-institutional research project.

BACKGROUND: Recent developments in imaging technology and tumor biology have led to new techniques to detect hypoxia and related alterations of the metabolic microenvironment in tumors. However, whether these new methods can predict radiobiological hypoxia and outcome after fractionated radiotherapy still awaits experimental evaluation. MATERIAL AND METHODS: The present article will introduce a multi-institutional research project addressing the impact of hypoxia and the metabolic microenvironment on radiotherapy of solid tumors. The four laboratories involved are situated at the universities of Dresden, Mainz, Munich and Würzburg, Germany. RESULTS: The joint scientific project started to collect data obtained on a set of ten different human tumor xenografts growing in nude mice by applying various imaging techniques to detect tumor hypoxia and related parameters of the metabolic microenvironment. These techniques include magnetic resonance imaging and spectroscopy, metabolic mapping with quantitative bioluminescence and single-photon imaging, histological multiparameter analysis of biochemical hypoxia, perfusion and vasculature, and immunohistochemistry of factors related to angiogenesis, invasion and metastasis. To evaluate the different methods, baseline functional radiobiological data including radiobiological hypoxic fraction and outcome after fractionated irradiation will be determined. CONCLUSION: Besides increasing our understanding of tumor biology, the project will focus on new, clinically applicable strategies for microenvironment profiling and will help to identify those patients that might benefit from targeted interventions to improve tumor oxygenation.

Animals↗

PubMed2004

Stereotactic boost irradiation for targets in the abdomen and pelvis.

Based on the experience of stereotactic irradiation of lung and liver tumors the feasibility of stereotactic boost irradiation to abdominal and pelvic tumors was evaluated. Twenty-one patients with inoperable tumors received a stereotactic boost of 2-3 x 5Gy/PTV-enclosing-100% isodose with normalization to 150% at the isocenter after normofractionated irradiation of 45-50.4Gy. Actuarial local control (16/21 targets) was 96/70% after 12 and 24 months. Treatment was feasible and well tolerated.

Abdominal Neoplasms↗

PubMed2004

A table top suited for CT and radiotherapy.

A radiotherapy table top was to be designed and manufactured, suitable for computer tomography in the same room. The aim was a distortion of the dose distribution by the table top of not more than 4% in small subunits of the target volume (TV) and less than 2% for the mean dose in the TV. Only negligible artifacts in the CT slices should occur in order to assure the exact relocalization of the TV. The table top manufactured of carbon fiber reinforced plastic was constructed by means of finite-element-algorithms. The trapezoidal shaped sandwich plate is supported with tapered beams. The small side of the table can penetrate a 60 cm CT-gantry. When turned, the table top allows large ap-pa opposed fields without irradiating through the beams. Transmission measurements were performed with an ionization chamber under different irradiation angles to determine the influence of the beams and the covering plate. Additionally, a portal imaging device (PID) was used for comparison. It was found that the deflection and torsion of the carbon fiber table top was smaller than for the original. The transmission of the sandwich plate was 97.5% (18 MV) and 96.5% (6 MV photons) respectively. If the irradiation of the beam walls can not be avoided the transmission is not in a critical range. The CT-slices show only minor artifacts along the side walls of the beams. The localization of the tumor or the TV is not restricted.

Artifacts↗

PubMed2004

Changing trends of incidence and prognosis of thyroid carcinoma in lower Franconia, Germany, from 1981-1995.

BACKGROUND: A population-based registry (PBR) in Lower Frankonia in southern Germany was conducted to evaluate the changes of incidence and prognosis of thyroid carcinoma (TC) in this area. METHODS: The study comprised 476 patients with differentiated thyroid carcinoma (DTC) from Lower Franconia (1.3 x 10(6) inhabitants) registered between 1981 and 1995 at the Regional Tumor Center. The incidence was assessed with respect to gender, age, histology, tumor stage, lymph node involvement and distant metastases in 5-year intervals (1981-1985, 1986-1990, and 1991-1995). RESULTS: An increasing rate of papillary thyroid carcinoma PTC and a decreasing rate of follicular thyroid carcinoma (FTC) were observed over the three time periods (1981-1985, 1986-1990, and 1991-1995). The overall incidence revealed no significant change with time for both females from 3.22 to 3.25 and 3.73 and males (1.07 to 1.54 and 1.69) between the three time periods. There was a significant improvement in outcome of patients with DTC with respect to life expectancy. CONCLUSIONS: Iodine prophylaxis does influence the distribution of the histologic types of thyroid cancer and leads to an increase in the ratio of papillary versus follicular carcinoma. Our study supports the hypothesis that the benefits of correcting iodine deficency outweigh the risks of iodine supplementation.

Adenocarcinoma, Follicular↗

PubMed2004

Is survival following post-operative radiotherapy in pN1-non-small cell lung cancer reduced? Results of a multivariate analysis.

Prognostic factors and the role of post-operative radiotherapy (PORT) in patients with pN1 nodal stage following surgery for NSCLC were identified. The clinical course of 211 patients with pN1 nodal involvement following thoracic surgery were reviewed, 97 of them received PORT. Multi-variate survival analysis with respect to prognostic factors (including treatment) was performed. The most frequent site of recurrence was the ipsilateral bronchus-stump or hilus (63% of recurrences). The 5-year rate of intercurrent deaths for PORT was 1% vs 6% in the group without PORT. The 5-year rate of locoregional recurrence was similar (24% vs 19%) for PORT vs no PORT (p=0.97). PORT patients had a higher rate of distant metastases (p=0.04). The 5-year rate of overall survival was 45% without PORT and 25% with PORT (p=0.003). Multivariate survival analysis identified 4 prognostic factors associated with decreased survival rate: age, extended pneumectomy, number of involved nodes and PORT dose. A PORT dose of 50 Gy corresponds to an increase in relative risk of death in the range of 1.5. Patients with PORT do not have an increased rate of intercurrent deaths. However in this cohort, PORT in pN1 patients was associated with a decreased survival rate due to distant metastases. Even after correction with respect to accepted prognostic factors in multivariate survival analysis, PORT was not able to improve or equalize prognosis of these negatively selected patients. The main site of recurrence is the bronchial stump and hilus. If PORT is applied in pN1 patients, a reduction of the target volume should be discussed since local control in high-risk patients may be of relevance.

Age Factors↗

PubMed2003

Secretory activity and cell cycle alteration of alveolar type II cells in the early and late phase after irradiation.

PURPOSE: Type II cells and the surfactant system have been proposed to play a central role in pathogenesis of radiation pneumonitis. We analyzed the secretory function and proliferation parameters of alveolar type II cells in the early (until 24 h) and late phase (1-5 weeks) after irradiation (RT) in vitro and in vivo. METHODS AND MATERIALS: Type II cells were isolated from rats according to the method of Dobbs. Stimulation of secretion was induced with terbutaline, adenosine triphosphate (ATP), and 12-O-tetradecanoylphorbol-13-acetate (TPA) for a 2-h period. Determination of secretion was performed using (3)H-labeled phosphatidylcholine. For the early-phase analysis, freshly isolated and adherent type II cells were irradiated in vitro with 9-21 Gy (stepwise increase of 3 Gy). Secretion stimulation was initiated 1, 6, 24, and 48 h after RT. For late-phase analysis, type II cells were isolated 1-5 weeks after 18 Gy whole lung or sham RT. Each experiment was repeated at least fivefold. Flow cytometry was used to determine cell cycle distribution and proliferating cell nuclear antigen index. RESULTS: During the early-phase (in vitro) analysis, we found a normal stimulation of surfactant secretion in irradiated, as well as unirradiated, cells. No change in basal secretion and no dose effect were seen. During the late phase, 1-5 weeks after whole lung RT, we observed enhanced secretory activity for all secretagogues and a small increase in basal secretion in Weeks 3 and 4 (pneumonitis phase) compared with controls. The total number of isolated type II cells, as well as the rate of viable cells, decreased after the second post-RT week. Cell cycle alterations suggesting an irreversible G(2)/M block occurred in the second post-RT week and did not resolve during the observation period. The proliferating cell nuclear antigen index of type II cells from irradiated rats did not differ from that of controls. CONCLUSION: In contrast to literature data, we observed no direct effect of radiation on secretory activity in the early phase after RT. In our study of isolated type II cells, as well as in intact animals, RT did not result in an impaired surfactant secretion up to 5 weeks after RT. Our in vivo experiments even showed an increased response of phosphatidylcholine secretion to all known secretagogues at Weeks 3 and 4 after whole lung RT, possibly due to inflammatory cytokines. Cell cycle alterations with G(2)/M block and cell loss in the late post-RT period may contribute more to the manifestation of radiation-induced lung damage than functional impairment in type II cells.

Animals↗

PubMed2003

A little to a lot or a lot to a little? An analysis of pneumonitis risk from dose-volume histogram parameters of the lung in patients with lung cancer treated with 3-D conformal radiotherapy.

PURPOSE: To determine whether a little dose to a large normal lung volume or a high dose to a small lung volume is more critical for induction of clinical pneumonitis. The second question is if dose-volume histogram (DVH) parameters are more reliable, if the lungs are analyzed as separate organs or as a whole organ. PATIENTS AND METHODS: We analyzed the clinical and DVH data from 49 patients treated for a thoracic malignancy using 3-D conformal treatment plans. 18 patients had developed a clinical pneumonitis (CTC II or III). The majority of patients (n = 48) received radiochemotherapy for non-small-cell lung cancer (NSCLC) with a combination of paclitaxel and carboplatin. Patients were generally treated 5 fx/week, single dose 2 Gy, using a two-series approach (shrinking field) up to a total dose of 60-70 Gy. For every individual patient, the overall dose distribution was recalculated in the Helax-TMS by means of adding dose plans according to the total dose applied in each series. The lungs were defined both as separate organs and as a whole organ. Low-dose volume (< or = 10 Gy, Vlow), moderate-dose volume (> 10-40 Gy, Vmod) and high-dose volume (> 40 Gy, Vhigh), as well as V10-V40 and mean lung dose (MLD) were defined from the cumulative DVH. Dose-effect relationships were fitted with a logistic regression model. RESULTS: Manifestation of clinical pneumonitis was within 3 months from termination of irradiation in all cases. For the ipsilateral lung, the incidence of pneumonitis was closely correlated to Vhigh. The pneumonitis rate increased from 13% up to 60%. By contrast, with increasing Vlow the pneumonitis rate dropped to < 10%. A similar but less pronounced effect was seen for the total lung. The lung volumes Vlow, Vmod and Vhigh of the ipsilateral, contralateral and whole lung were significantly correlated to the corresponding MLD. The incidence of pneumonitis increased with increasing MLD for the ipsilateral lung with a D50 of 32 Gy and a gamma 50 of 0.98. For the whole lung, the observed increase was less steep. MLD showed a close correlation to NTCP calculated by the Kutcher model. However, NTCP calculation overestimated the pneumonitis risk for the ipsilateral lung and underestimated the risk for the whole lung due to the steeper gradient. The logistic regression curve for the DVH parameters V10-V40 showed an increase of steepness toward higher doses. From the logistic regression curves, a DVH template indicating critical borders of V10-V40 was generated for the ipsilateral as well as for the total lung. CONCLUSION: Our data indicate that it is reasonable to disperse the dose outside the target volume over large areas in order to reduce the volumes of lung receiving > 40 Gy. Reducing the high-dose volume reduces the pneumonitis rate more than a corresponding reduction in the low-dose regions of the DVH. Landmarks for DVH optimization as defined in this analysis may serve as a basis for DVH contrains in IMRT planning. Separate organ analysis produced more reliable results and should be preferred to whole-organ analysis, if techniques mainly involving one side of the lung are applied. Further validation of these constraints is necessary prior to general recommendation.

Aged↗

PubMed2003

[Present status of treatment in nasopharyngeal carcinoma?].

AIM: Review of the evolution of combined treatment strategies in nasopharyngeal carcinoma. RESULTS: Radiotherapy is accepted standard for treatment of nasopharyngeal cancer. Nevertheless, there is no uniform opinion with regard to doses, fractionation, technique or use of systemic chemotherapy. It is hardly possible to compare the results of recent and historical trials because of different staging systems and because nasopharyngeal cancer occurring in the Oceano-Asian region are biologically different to those in Western countries. Conclusions drawn from former, mostly retrospective analyses are not applicable to newer standards regarding the developments in diagnostics and therapy. Presently simultaneous chemoradiotherapy is standard for lymph node positive nasopharyngeal cancer. CONCLUSIONS: It will be necessary to treat patients with different histologic subtypes with an uniform treatment schedule to define the place of combined modality treatment. This will probably be the only way to develop treatment concepts for distinct stages and biological entities.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2003

Preoperative irradiation for prevention of heterotopic ossification following prosthetic total hip replacement results of a prospective study in 462 hips.

BACKGROUND: The effectiveness of pre- or postoperative radiotherapy for prevention of heterotopic ossification (HO) following total hip replacement (THR) has already been demonstrated in the past. Thereby, in most studies using preoperative radiotherapy patients were irradiated < 6 h before surgery. The purpose of this prospective study was to analyze the effectiveness of preoperative irradiation on the evening before surgery and to identify risk factors for HO in a homogeneous collective of patients. PATIENTS AND METHODS: From July 1997 to July 2001, 416 patients (462 hips; 235 males, 227 females) received preoperative radiotherapy of the hip on the evening before surgery with a 7-Gy single fraction. The patients' median age was 67.1 years. The most frequent indication for radiotherapy was hypertrophic osteoarthritis (383 hips, 82.9%). Treatment results were assessed by comparison of pre- and postoperative hip X-rays (immediately and 6 months after surgery). The analysis of radiographs was performed according to the Brooker score. RESULTS: The overall incidence of HO was 18.1% (n = 84), Brooker score 1 12.3% (n = 57), score 2 3.9% (n = 18), score 3 1.5% (n = 7), and score 4 0.4% (n = 2). Sex, body height, hypertrophic osteoarthritis of higher degree, size of the femoral component of the prosthesis, previous ipsi- or contralateral HO, and short course of nonsteroidal anti-inflammatory drug (diclofenac) therapy significantly influenced the HO rate in univariate analysis. In multivariate analysis, an interdependence of prosthesis size, sex and patient's height was found. From these three variables, only prosthesis size was statistically significant in multivariate analysis. The cumulative dose of diclofenac (< or = 300 mg or > 300 mg) within the first 7 postoperative days and previous ipsi- or contralateral HO influenced the incidence of HO in multivariate analysis. CONCLUSION: Preoperative radiotherapy on the evening before surgery is an effective treatment modality to reduce overall (Brooker 1-4) and clinically relevant, severe HOs (Brooker 3-4), and includes several advantages compared to postoperative irradiation. Previous ipsi- and contralateral HOs were identified as high risk factors for HO in this study. In patients with these risk factors, the incidence of HO increased.

Adult↗

PubMed2003

Association of anorectal dose-volume histograms and impaired fecal continence after 3D conformal radiotherapy for carcinoma of the prostate.

PURPOSE: The late toxicity of fecal incontinence after pelvic radiotherapy is now frequently recognized but the etiology poorly understood. We therefore investigated associations between dose-volume histogram (DVH) parameters of the rectum and the anal canal with fecal continence as measured by an established 10-item questionnaire. METHODS AND MATERIALS: Forty-four patients treated for carcinoma of the prostate with 58-72 Gy of 3D conformal radiotherapy between 1995 and 1999 who completed the questionnaire formed the study population. Total continence scores of treated patients obtained 1.5 years (median) after radiotherapy were compared to a control group of 30 patients before radiotherapy. Median, mean, minimum and maximum doses as well as the volume (% and ml) treated to 40, 50, 60 and 70 Gy were determined separately for anal canal and rectum. DVH parameters were correlated with total continence score (Spearman rank test) and patients grouped according to observed continence were compared regarding DVH values (Mann-Whitney U-test). RESULTS: Median fecal continence scores were significantly worse in the irradiated than in the control group (31 vs. 35 of a maximum 36 points). In treated patients, 59%/27%/14% were classified as fully continent, slightly incontinent and severely incontinent. Continence was similar in the 58-to-62-Gy, 66-Gy and 68-to-72-Gy dose groups. No DVH parameter was significantly correlated with total continence score, but severely incontinent patients had a significantly higher minimum dose to the anal canal than fully continent/slightly incontinent, accompanied by portals extending significantly further inferiorly with respect to the ischial tuberosities. CONCLUSIONS: Excluding the inferior part of the anal canal from the treated volume in 3D conformal therapy for carcinoma of the prostate appears to be a promising strategy to prevent radiation-induced fecal incontinence.

Aged↗

PubMed2003

Impact of target reproducibility on tumor dose in stereotactic radiotherapy of targets in the lung and liver.

BACKGROUND AND PURPOSE: Previous analyses of target reproducibility in extracranial stereotactic radiotherapy have revealed standard security margins for planning target volume (PTV) definition of 5mm in axial and 5-10mm in longitudinal direction. In this study the reproducibility of the clinical target volume (CTV) of lung and liver tumors within the PTV over the complete course of hypofractionated treatment is evaluated. The impact of target mobility on dose to the CTV is assessed by dose-volume histograms (DVH). MATERIALS AND METHODS: Twenty-two pulmonary and 21 hepatic targets were treated with three stereotactic fractions of 10 Gy to the PTV-enclosing 100%-isodose with normalization to 150% at the isocenter. A conformal dose distribution was related to the PTV, which was defined by margins of 5-10mm added to the CTV. Prior to each fraction a computed tomography (CT)-simulation over the complete target volume was performed resulting in a total of 60 CT-simulations for lung and 58 CT-simulations for hepatic targets. The CTV from each CT-simulation was segmented and matched with the CT-study used for treatment planning. A DVH of the simulated CTV was calculated for each fraction. The target coverage (TC) of dose to the simulated CTV was defined as the proportion of the CTV receiving at least the reference dose (100%). RESULTS: A decrease of TC to <95% was found in 3/60 simulations (5%) of pulmonary and 7/58 simulations (12%) of hepatic targets. In two of 22 pulmonary targets (9%) and in four of 21 hepatic targets (19%) a TC of <95% occurred in at least one fraction. At risk for a decreased TC <95% were pulmonary targets with increased breathing mobility and hepatic targets with a CTV exceeding 100 cm(3). CONCLUSIONS: Target reproducibility was precise within the reference isodose in 91% of lung and 81% of liver tumors with a TC of the complete CTV >or=95% at each fraction of treatment. Pulmonary targets with increased breathing mobility and liver tumors >100 cm(3) are at risk for target deviation exceeding the standard security margins for PTV-definition at least for one fraction and require individual evaluation of sufficient margins.

Adolescent↗

PubMed2003

Quantitative tissue perfusion measurements in head and neck carcinoma patients before and during radiation therapy with a non-invasive MR imaging spin-labeling technique.

PURPOSE: Tumor blood flow, tumor tissue perfusion and oxygen supply have substantial influence on the responsiveness of tumors to radiotherapy. This study was aimed at implementing and evaluating a non-invasive functional magnetic resonance (MR) imaging spin-labeling technique at a main magnetic field strength of 2T for measuring tissue perfusion changes in head and neck carcinoma patients before and during radiotherapy. METHODS: Tissue perfusion was determined quantitatively in ten patients with head and neck cancer. Five patients were investigated twice during radiation therapy. For perfusion measurements, a non-invasive MR spin-labeling technique was employed: The longitudinal relaxation time T(1) was measured with segmented Snapshot-FLASH imaging after either slice-selective or non-selective spin inversion. Perfusion values were calculated pixelwise employing a two-compartment tissue model. With this technique no contrast agents are required so that repetitive measurements are possible. Perfusion images with a slice thickness of 10mm and an in-plane resolution of 1.9x2.8mm(2) were acquired at a total scan time of 8:30min per scan. RESULTS: With the non-invasive MR imaging technique it was possible to visualize tumor and normal tissue perfusion as well as perfusion changes in the course of radiotherapy with a spatial resolution of less than 3mm. Among the investigated subjects measured tumor perfusion and changes in perfusion were heterogenous. In 4/5 patients studied at the start and end of radiotherapy, perfusion decreased, while in one patient there was an increase. CONCLUSIONS: A method is presented that allows non-invasive and repetitive characterization of tissue perfusion. This parameter may be used for treatment stratification, especially in treatments that use vasomodulation or anti-angiogenic agents.

Algorithms↗

PubMed2003

Induction chemotherapy with paclitaxel and cisplatin and CT-based 3D radiotherapy in patients with advanced laryngeal and hypopharyngeal carcinomas--a possibility for organ preservation.

BACKGROUND: To evaluate the effect of paclitaxel/cisplatin induction chemotherapy (ICHT) and CT-based radiotherapy (RT) on larynx preservation, tumor control, and survival in patients with larynx/hypopharynx carcinoma eligible for total laryngectomy (TL) or TL plus partial pharyngectomy (TLPP). PATIENTS AND METHODS: Fifty patients eligible for TL or TLPP were enrolled onto a prospective study and treated with ICHT (200 mg/m(2) paclitaxel, 100 mg/m(2) cisplatin; day 1, 22). In patients with complete or partial tumor response RT (69.9 Gy in 5.5 weeks at the gross tumor, 50.4 Gy in the lymphatic drainage; single dose: 1.8 Gy, concomitant boost: 1.5 Gy) was applied. Non-responders had TL/TLPP and RT with total doses adapted to the radicality of tumor resection (56-70 Gy). RESULTS: The response rate to ICHT was 88% (10% complete, 78% partial response). At a median follow-up period of 25 months the larynx preservation rate was 84%. The 2-year local-regional control rate was 91% and the 2-year overall survival rate was 72.3%. The 3-year estimate to survive with functional larynx is 60%. CONCLUSION: In a large portion of patients eligible for TL or TLPP the larynx was preserved by paclitaxel/cisplatin ICHT and 3D RT.

Adult↗

PubMed2003

The relationship between belly board position and patient anatomy and its influence on dose-volume histogram of small bowel for postoperative radiotherapy of rectal cancer.

The influence of three different belly board (BB) positions in radiotherapy of rectal cancer on the dose-volume histogram of the small bowel (SB) were analysed for 20 patients. Placing the lower border of the BB opening near the lumbosacral junction, both the volume of SB within the pelvis and the volume of SB within all tested dose levels were lower compared to its position near the symphysis or the lumbosacral junction.

Adult↗

PubMed2003

[Emotional distress and needs for psychosocial support among breast cancer patients at start of radiotherapy].

Radiotherapy is considered to be associated with psychological distress in cancer patients. The present pilot study was aimed at exploring both emotional distress and support needs among patients with primary breast cancer. 77 women were evaluated at the start of radiotherapy after completion of their breast-conserving surgical treatment. Emotional distress was measured with the Hospital Anxiety and Depression Scale and the Hornheider Questionnaire. Needs for additional psychosocial support as well as acceptance of support were assessed by single items. In addition to the patients' views, ratings from physicians, nurses and technical assistants were obtained. Although according to their self-reports only one third of the patients wished to talk about their disease and almost all of them had sufficient opportunities for discussions with their family members, 36 % reported needs for additional support and 75 % said that they would be willing to accept support in the case that it would be offered to them. Emotional distress and support needs were rated even higher by the members of the medical team. 20 % of the patients had high values (> 10) on the anxiety subscale and 5 % had high values (> 10) on the depression subscale of the HADS. 37 % were distressed according to the Hornheider Questionnaire. However, neither the HADS nor the Hornheider Questionnaire were sufficiently sensitive and specific to detect those patients reporting support needs. It was concluded that better screening tools have to be developed for identifying breast cancer patients in need of psychosocial support during radiotherapy.

Adult↗