Peter Lukas

Tumor microcirculation and diffusion predict therapy outcome for primary rectal carcinoma

PURPOSE The aim of our study was to correlate perfusion indices and apparent diffusion coefficients with therapy outcome after chemoradiation. METHODS AND MATERIALS In 34 patients with primary rectal carcinoma (cT3) undergoing preoperative chemoradiation, pretherapeutic perfusion indices and apparent diffusion coefficients were obtained by dynamic or diffusion-weighted magnetic resonance imaging. Therapy response was defined if the pathologic observation revealed no invasion into the perirectal fat after chemoradiation. RESULTS In 18 patients, a response and in 16, no response was observed. Statistically significant differences were found for the mean perfusion index (p < 0.001; 7.5 +/- 1.5 mL/min/100 g vs. 10.7 +/- 2.7 mL/min/100 g) and for the intratumoral cumulative fraction of pixels with perfusion-indices > 12 mL/min/100 g (p < 0.001, 3.7 +/- 4.0% vs. 24.7 +/- 17.9%). A three-way ANOVA resulted in significant effects for therapy responder/nonresponder (p < 0.001) and for apparent diffusion coefficient and the individual patients. CONCLUSION Perfusion indices and apparent diffusion coefficients inside the tumor region seem to be of predictive value for therapy outcome of preoperative therapy in patients with primary rectal carcinoma. Higher parameter levels in the nonresponding group could be explained by increased shunt flow or increased angiogenic activity in aggressive tumor cell clusters resulting in reduced nutrients supply and higher fraction of intratumoral necrosis respectively.

Determination of volatile organic compounds in exhaled breath of patients with lung cancer using solid phase microextraction and gas chromatography mass spectrometry

Abstract Background: Analysis of exhaled breath is a promising diagnostic method. Sampling of exhaled breath is non-invasive and can be performed as often as considered desirable. There are indications that the concentration and presence of certain of volatile compounds in exhaled breath of lung cancer patients is different from concentrations in healthy volunteers. This might lead to a future diagnostic test for lung cancer. Methods: Exhaled breath samples from 65 patients with different stages of lung cancer and undergoing different treatment regimes were analysed. Mixed expiratory and indoor air samples were collected. Solid phase microextraction (SPME) with carboxen/polydimethylsiloxane (CAR/PDMS) sorbent was applied. Compounds were analysed by means of gas chromatography (GC) and mass spectrometry (MS). Results: The method we used allowed identification with the spectral library of 103 compounds showing at least 15% higher concentration in exhaled breath than in inhaled air. Among those 103 compounds, 84 were confirmed by determination of the retention time using standards based on the respective pure compound. Approximately, one third of the compounds detected were hydrocarbons. We found aromatic hydrocarbons, alcohols, aldehydes, ketones, esters, ethers, sulfur compounds, nitrogen-containing compounds and halogenated compounds. Acetonitrile and benzene were two of 10 compounds which correlated with smoking behaviour. A comparison of results from cancer patients with those of 31 healthy volunteers revealed differences in the concentration and presence of certain compounds. The sensitivity for detection of lung cancer patients based on eight different compounds not seen in exhaled breath of healthy volunteers was 51% and the specificity was 100%. These eight potential markers for detection of lung cancer are 1-propanol, 2-butanone, 3-butyn-2-ol, benzaldehyde, 2-methyl-pentane, 3-methyl-pentane, n-pentane and n-hexane. Conclusions: SPME is a relatively insensitive method and compounds not observed in exhaled breath may be present at a concentration lower than LOD. The main achievement of the present work is the validated identification of compounds observed in exhaled breath of lung cancer patients. This identification is indispensible for future work on the biochemical sources of these compounds and their metabolic pathways. Clin Chem Lab Med 2009;47:550–60.

Diffusion-weighted magnetic resonance imaging for monitoring diffusion changes in rectal carcinoma during combined, preoperative chemoradiation: preliminary results of a prospective study.

PURPOSE To evaluate the clinical value of diffusion-weighted magnetic resonance imaging (DW-MRI) to monitor response of primary carcinoma of the rectum to preoperative chemoradiation by measuring tumor apparent diffusion coefficient (ADC). MATERIALS AND METHODS Diffusion data of nine patients undergoing preoperative combined chemoradiation for clinical staged T3, N(0-2), M(0) carcinoma of the rectum were analyzed. Diffusion-weighted echo-planar MR images were obtained prior to and at specified intervals during chemoradiation and ADCs calculated from acquired tumor images. RESULTS Comparison of mean ADC and cumulative radiation dose showed a significant decrease of mean ADC at the 2nd (P = 0.028), 3rd (P = 0.012), and 4th (P = 0.008) weeks of treatment. Cytotoxic edema and fibrosis were considered as reasons for ADC decrease. CONCLUSION This study demonstrated tumor ADC changes via detection of therapy-induced alterations in tumor water mobility. Our results indicate that diffusion-weighted imaging may be a valuable clinical tool to diagnose the early stage of radiation-induced fibrosis.

Involved-Node Radiotherapy in Early-Stage Hodgkin’s Lymphoma

Background and Purpose:Radiotherapy of Hodgkin’s lymphoma has evolved from extended-field to involved-field (IF) radiotherapy reducing toxicity whilst maintaining high cure rates. Recent publications recommend further reduction in the radiation field to involved-node (IN) radiotherapy; however, this concept has never been tested in a randomized trial. The German Hodgkin Study Group aims to compare it with standard IF radiotherapy in their future HD17 trial.Patients and Methods:All patients must be examined by the radiation oncologist before the start of chemotherapy. At that time, patients must have complete staging CT scans. For patients with IN radiotherapy, a radiation planning CT before and after chemotherapy with patients in the treatment position is recommended. Fusion techniques, allowing the overlapping of the pre- and postchemotherapy CT scans, should be used. Usage of PET-CT scans with patients in the treatment position is recommended, whenever possible.Results:The clinical target volume encompasses the initial volume of the lymph node(s) before chemotherapy and incorporates the initial location and extent of the disease taking the displacement of the normal tissues into account. The margin of the planning target volume should be 2 cm in axial and 3 cm in craniocaudal direction. If necessary, it can be reduced to 1–1.5 cm. To minimize lung and cardiac toxicity, the target definition in the mediastinum is different.Conclusion:The concept of IN radiotherapy has been proposed as a means to further improve the therapeutic ratio by reducing the risk of radiation-induced toxicity, including second malignancies. Field sizes will further decrease compared to IF radiotherapy.Hintergrund und Ziel:Die Strahlenbehandlung des Hodgkin-Lymphoms entwickelte sich von der Extended-Field- zur Involved-Field-(IF-)Radiotherapie bei anhaltend hohen Heilungsraten. Kürzlich erschienene Publikationen empfehlen die weitere Reduktion der Bestrahlungsvolumina hin zur Involved-Node-(IN-)Radiotherapie. Allerdings ist dieses Vorgehen bislang nicht innerhalb randomisierter klinischer Studien geprüft worden. Daher wird die Deutsche Hodgkin-Lymphom-Studiengruppe in der zukünftigen HD17-Studie die IF- mit der IN-Radiotherapie vergleichen (Abbildung 1).Patienten und Methodik:Alle Studienpatienten müssen vor dem Start der Chemotherapie vom Radioonkologen untersucht werden. Zu diesem Zeitpunkt muss ein vollständiges bildgebendes Staging vorliegen. Für Patienten, die eine IN-Radiotherapie erhalten, wird ein Planungs-CT in Bestrahlungsposition vor und nach der Chemotherapie empfohlen. Die Überlagerung (Matching) des prätherapeutischen Planungs-CT mit dem Planungs-CT nach Chemotherapie ist wünschenswert. Steht eine prätherapeutische PET-CT zur Verfügung, sollte diese in die Zielvolumendefinition im Rahmen der IN-Radiotherapie einbezogen werden.Ergebnisse:Das klinische Zielvolumen (CTV) umfasst die initial als befallen gewerteten Lymphknoten. Es berücksichtigt die initiale Ausdehnung der Erkrankung inklusive der Verlagerung von Normalgeweben. Der Sicherheitssaum des Planungszielvolumens (PTV) sollte in axialer Ausdehnung 2 cm, in kraniokaudaler Ausrichtung 3 cm betragen (Abbildung 2). Er kann in axialer Ausdehnung auf 1–1,5 cm reduziert werden, um Organtoxizitäten möglichst gering zu halten. Um die pulmonale und kardiale Toxizität gering zu halten, wird im Mediastinum ein anderes Vorgehen empfohlen (Abbildung 3).Schlussfolgerung:Das Konzept der IN-Radiotherapie soll das Auftreten radiogener Toxizitäten inklusive Zweitneoplasien weiter minimieren. Die Feldgrößen werden im Vergleich zur IF-Radiotherapie weiter abnehmen (Abbildung 4).

Low-dose radiation is sufficient for the noninvolved extended-field treatment in favorable early-stage Hodgkin's disease: long-term results of a randomized trial of radiotherapy alone.

PURPOSE To show that radiotherapy (RT) dose to the noninvolved extended field (EF) can be reduced without loss of efficacy in patients with early-stage Hodgkins disease (HD). PATIENTS AND METHODS During 1988 to 1994, pathologically staged patients with stage I or II disease who were without risk factors (large mediastinal mass, extranodal lesions, massive splenic disease, elevated erythrocyte sedimentation rate, or three or more involved areas) were recruited from various centers. All patients received 40 Gy total fractionated dose to the involved field areas but were randomly assigned to receive either 40 Gy (arm A) or 30 Gy (arm B) total fractionated dose for the clinically noninvolved EF. No chemotherapy was given. RT films were prospectively reviewed for protocol violations and recurrences retrospectively related to the applied RT. RESULTS Of 382 recruited patients, 376 were eligible for randomized comparison, 190 in arm A and 186 in arm B. Complete remission was attained in 98% of patients in each arm. With a median follow-up of 86 months, 7-year relapse-free survival (RFS) rates were 78% (arm A) and 83% (arm B) (P =.093). The upper 95% confidence limit for the possible inferiority of arm B in RFS was 4%. Corresponding overall survival rates were 91% (arm A) and 96% (arm B) (P =.16). The most common causes of death (n = 27) were cardiorespiratory disease/pulmonary embolisms (seven), second malignancy (six), and HD (five). Protocol violation was associated with significantly poorer RFS. Nonirradiated nodes were involved in 42 of 52 reviewed relapses, infield areas in 18, marginal areas in 17, and extranodal sites in 16. CONCLUSION EF-RT alone attains good survival rates in favorable early-stage HD. The 30-Gy dose is adequate for clinically noninvolved areas. Protocol violation worsens the subsequent prognosis. Relapse patterns suggest that systemic therapy can reduce the 20% long-term relapse rate.

Intracellular signaling pathways regulating radioresistance of human prostate carcinoma cells

Radiation therapy plays an important role in the management of prostate carcinoma. However, the problem of radioresistance and molecular mechanisms by which prostate carcinoma cells overcome cytotoxic effects of radiation therapy remains to be elucidated. In order to investigate possible intracellular mechanisms underlying the prostate carcinoma recurrences after radiotherapy, we have established three radiation‐resistant prostate cancer cell lines, LNCaP‐IRR, PC3‐IRR, and Du145‐IRR derived from the parental LNCaP, PC3, and Du145 prostate cancer cells by repetitive exposure to ionizing radiation. LNCaP‐IRR, PC3‐IRR, and Du145‐IRR cells (prostate carcinoma cells recurred after radiation exposure (IRR cells)) showed higher radioresistance and cell motility than parental cell lines. IRR cells exhibited higher levels of androgen and epidermal growth factor (EGF) receptors and activation of their downstream pathways, such as Ras‐mitogen‐activated protein kinase (MAPK) and phosphatidyl inositol 3‐kinase (PI3K)‐Akt and Jak‐STAT. In order to define additional mechanisms involved in the radioresistance development, we determined differences in the proteome profile of parental and IRR cells using 2‐D DIGE followed by computational image analysis and MS. Twenty‐seven proteins were found to be modulated in all three radioresistant cell lines compared to parental cells. Identified proteins revealed capacity to interact with EGF and androgen receptors related signal transduction pathways and were involved in the regulation of intracellular routs providing cell survival, increased motility, mutagenesis, and DNA repair. Our data suggest that radioresistance development is accompanied by multiple mechanisms, including activation of cell receptors and related downstream signal transduction pathways. Identified proteins regulated in the radioresistant prostate carcinoma cells can significantly intensify activation of intracellular signaling that govern cell survival, growth, proliferation, invasion, motility, and DNA repair. In addition, such analyses may be utilized in predicting cellular response to radiotherapy.

Preliminary Results on the Influence of Chemoradiation on Apparent Diffusion Coefficients of Primary Rectal Carcinoma Measured by Magnetic Resonance Imaging

Purpose:To study changes of the apparent diffusion coefficient (ADC) measured by magnetic resonance imaging (MRI) in patients with primary rectal carcinoma during a course of combined chemoradiation.Patients and Methods:Diffusion-weighted echo-planar imaging at 1.5 T was performed in patients (n = 8) with primary rectal carcinoma (cT3) undergoing preoperative chemoradiation. Mean tumor ADC values and ADC histograms were determined and compared weekly during the course of therapy. Surgical resection of the tumors enabled a correlation of ADC values with the pathologic classification.Results:In four patients tumor T-downstaging (ypT0–2) was observed, and in four patients no downstaging (ypT3) was seen. In all patients, ADC values were higher before onset of chemoradiation therapy compared to the end of chemoradiation. Separating the patients into two groups, a significant increase in ADC value during week 1 of therapy, followed by a steady decrease, was found for the therapy-responder group. In the nonresponder group, no initial increase of ADC values was observed. After the 1st week of therapy, ADC values were significantly lower in the nonresponder group during the remaining duration of therapy.Conclusion:With these preliminary results it could be shown that MR diffusion imaging is able to detect individual changes of tumor ADC values during the course of combined chemoradiation reflecting biological changes within the tumor tissue. Further studies will be necessary to prove the possible value of totally noninvasive ADC imaging on predicting therapy outcome.Ziel:Untersuchung von Änderungen des mittels diffusionsgewichteter Magnetresonanztomographie (DMRT) gemessenen Diffusionskoeffizienten (ADC) in primären Rektumkarzinomen während kombinierter Radiochemotherapie.Patienten und Methodik:Diffusionsgewichtete echoplanare Bildgebung wurde an einem 1,5-T-MR-Gerät bei Patienten (n = 8) mit primären Rektumkarzinomen (cT3) während kombinierter Radiochemotherapie durchgeführt. Mittlere Tumor-ADC-Werte und ADC-Histogramme wurden im Verlauf der Therapie wöchentlich erfasst und verglichen. Die sich an die Therapie anschließende chirurgische Resektion des Tumors ermöglichte eine Korrelation der ADC-Werte mit der pathologischen Klassifikation.Ergebnisse:Bei vier Patienten wurde eine Verbesserung des Tumorstadiums (ypT0–2) beobachtet, und bei vier Patienten war keine Verbesserung des Tumorstadiums (ypT3) feststellbar. Zwischen Anfang und Ende der Therapie kam es bei allen Patienten zu einer signifikanten Abnahme der mittleren ADC-Werte. Für die Patientengruppe mit Verbesserung des Tumorstadiums wurde ein signifikanter Anstieg der ADC-Werte während der 1. Therapiewoche, gefolgt von einer stetigen Abnahme, beobachtet. Für die Patientengruppe ohne Verbesserung des Tumorstadiums wurde keine ADC-Zunahme während der 1. Therapiewoche festgestellt. Nach der 1. Therapiewoche waren die ADC-Werte für die Gruppe ohne Verbesserung des Tumorstadiums signifikant niedriger als für die Gruppe mit Verbesserung des Tumorstadiums.Schlussfolgerung:Diese vorläufigen Ergebnisse zeigen, dass die DMRT in der Lage ist, individuelle Änderungen der ADC-Werte, die biologische Veränderungen im Tumorgewebe widerspiegeln, während kombinierter Radiochemotherapie zu detektieren. Weitere Studien sind notwendig, um die mögliche Bedeutung der vollständig nichtinvasiven DMRT für die Vorhersage des Therapieergebnisses nachzuweisen.

Repositioning Accuracy: Comparison of a Noninvasive Head Holder with Thermoplastic Mask for Fractionated Radiotherapy and a Case Report

PURPOSE To compare accuracy, clinical feasibility, and subjective patient impression between a noninvasive head holder (Vogele Bale Hohner [VBH]; Wellhoefer Dosimetry, Schwarzenbruck, Germany) developed at the University of Innsbruck and the thermoplastic mask fixation system for use in fractionated external radiotherapy. We present a case report of an actual patient fixated in the VBH head holder during radiation therapy. MATERIALS AND METHODS The VBH head holder consists of an individualized vacuum dental cast connected to a head plate via two hydraulic arms allowing noninvasive, reproducible head fixation of even uncooperative patients. Accuracy was tested and compared with that of the thermoplastic mask using the Phillips EasyGuide navigation system on five volunteers. Specific external registration points served as landmarks and their positions were compared after each repositioning. System and operator inaccuracy were also taken into account. The times taken for production and repositioning of the respective fixation devices were compared, and subjective impressions were noted. RESULTS Mean VBH head holder repositioning accuracy was 1.02 mm while that of the thermoplastic mask was 3.05 mm. 69% of mask repositionings showed a deviation > 2 mm and 41% > 3 mm (as opposed to 8% and 1% respectively for the VBH head holder) Those points located farthest away from the respective plane of fixation showed the largest deviations. Both production and repositioning times were similar between the systems; depending upon the patient, the VBH head holder was generally better tolerated than the mask system. CONCLUSION Due to its significantly better repositioning accuracy compared to that of the thermoplastic mask, the VBH head holder is especially suited for external radiation requiring precise repositioning due to critical tissues in immediate surrounding of the area to be irradiated.

MPC-6827: A Small-Molecule Inhibitor of Microtubule Formation That Is Not a Substrate for Multidrug Resistance Pumps

A novel series of 4-arylaminoquinazolines were identified from a cell-based screening assay as potent apoptosis inducers. Through structure-activity relationship studies, MPC-6827 and its close structural analogue, MPI-0441138, were discovered as proapoptotic molecules and mitotic inhibitors with potencies at low nanomolar concentrations in multiple tumor cell lines. Photoaffinity and radiolabeled analogues of MPC-6827 were found to bind a 55-kDa protein, and this binding was competed by MPC-6827, paclitaxel, and colchicine, but not vinblastine. MPC-6827 effectively inhibited the polymerization of tubulin in vitro, competed with colchicine binding, and disrupted the formation of microtubules in a variety of tumor cell lines, which together showed the molecular target as tubulin. Treatment of MCF-7 breast carcinoma or Jurkat leukemia cells with MPC-6827 led to pronounced G2-M cell cycle arrest followed by apoptosis. Apoptosis, as determined by terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling assay, was preceded by loss of mitochondrial membrane potential, cytochrome c translocation from mitochondria to nuclei, activation of caspase-3, and cleavage of poly(ADP-ribose) polymerase. MPC-6827 was equipotent in an in vitro growth inhibition assay in several cancer cell lines regardless of the expression levels of the multidrug resistance ABC transporters MDR-1 (Pgp-1), MRP-1, and BCRP-1. In B16-F1 allografts and in OVCAR-3, MIAPaCa-2, MCF-7, HT-29, MDA-MB-435, and MX-1 xenografts, statistically significant tumor growth inhibition was observed with MPC-6827. These studies show that MPC-6827 is a microtubule-disrupting agent with potent and broad-spectrum in vitro and in vivo cytotoxic activities and, therefore, MPC-6827 is a promising candidate for development as a novel therapeutic for multiple cancer types.

Decreased High-Energy Phosphate Ratios in the Myocardium of Men with Diabetes Mellitus Type I

AIMS/HYPOTHESIS To investigate whether alterations in high-energy phosphates occur in the myocardium of persons with diabetes mellitus type I. Microvascular abnormalities and dysfunction via thickening of the basement membrane are known to occur in diabetic patients. Myocardial high-energy phosphates have been shown to be reduced by ischemia, and alterations of the cardiac metabolism are the primary consequence of myocardial ischemia. METHODS The present study involved 34 male patients (mean age 35.5 +/- 10.1) with diabetes mellitus type I and 35 healthy male volunteers (mean age 36 +/- 8.6) as age-matched controls. Phosphorus-31 magnetic resonance spectroscopic imaging of the heart was performed in all subjects using a 1.5-T whole-body magnetic resonance scanner. The ratios of phosphocreatine (PCr) to beta-adenosinetriphosphate (beta-ATP) were calculated. Moreover, echocardiographic evaluation and stress tests were performed in all individuals. RESULTS The myocardium of patients with diabetes mellitus type I showed significantly decreased ratios of PCr to beta-ATP compared with healthy controls in the left ventricle (1.90 +/- 0.4 vs. 2.15 +/- 0.3, p < 0.05). We found a moderate negative correlation between the ratio of PCr to beta-ATP in the left ventricle and both, the diastolic left ventricular function (E/A; r = -0.41) and the glycohemoglobin A1c (GHbA1c; r = -0.42). CONCLUSION This study demonstrates for the first time a decreased ratio of PCr to beta-ATP in the myocardium of persons with diabetes mellitus type I without a known history of coronary heart disease.