Ingeborg Küchler

Genetic Imbalances with Impact on Survival in Head and Neck Cancer Patients

Chromosomal imbalances in 113 primary head and neck squamous cell carcinomas (HNSCCs) determined by comparative genomic hybridization were correlated with patients survival using custom-made computer software which enabled the assessment of individual chromosomal loci. The Kaplan-Meier analysis revealed that overrepresentations of 2q12, 3q21-29, 6p21.1, 11q13, 14q23, 14q24, 14q31, 14q32, 15q24, 16q22, and deletions of 8p21-22 and 18q11.2 were significantly associated with both shorter disease-free interval and disease-specific survival in this tumor collective. Multivariate Cox proportional hazards regression models consistently identified the gains of 3q21-29, 11q13, and the loss of 8p21-22 as independent prognostic markers carrying a higher significance than the nodal status as the only clinicopathological parameter with statistical importance. In addition, these three markers allowed a molecular dissection of the patients with low clinical risk (pN0 and pT2 tumors). Thus, the genomic data being derived from the evaluation of primary HNSCC enabled a stratification of the patients into subgroups with different survival highlighting the necessity of a genetically based tumor classification for refining diagnosis and treatment of HNSCC patients.

Sequential statistical procedures for processes of the exponential class with independent increments

In this survey paper sequential statistical procedures for the exponential class of processes with independent increments are considered. After the definition of the exponential class a characterization in terms of the LEVY-CHXNTCBXN.representation is given. Then, sequential estimation problems* and sequential testing of hypotheses with respect to the underlying parameter are studied. Finally, some possible extensions of the considered notions and methods to other classes of processes are indicated.

Verbesserte Prognoseeinschätzung bei Kopf-Hals-Karzinomen durch neue genetische Marker

ZusammenfassungDie Prognose von Patienten mit Kopf-Hals-Karzinomen lässt sich anhand der etablierten Stagingparameter oft nur sehr ungenügend einschätzen. Auf der Suche nach neuen Markern, die den Tumorphänotyp genauer charakterisieren, wurden in der vorliegenden Studie 100 primäre Plattenepithelkarzinome des Kopf-Hals-Bereichs mit Hilfe der Comparativen Genomischen Hybridisierung (CGH) molekularzytogenetisch untersucht. Die detektierten genetischen Veränderungen (Deletionen oder DNA-Überrepräsentierungen bzw. Amplifikationen) wurden für jeden Chromosomarm aufgeschlüsselt und statistisch zusammen mit den klinisch-pathologischen Daten uni- und multivariat hinsichtlich ihrer prognostischen Aussagefähigkeit überprüft. Alle Patienten dieser Studie wurden primär operiert und in Abhängigkeit vom Tumorstadium adjuvant nachbestrahlt. In dem längstens 4-jährigen Beobachtungszeitraum waren von den 100 Patienten 29 am Tumorleiden verstorben. Die kumulierten Überlebensraten nach der Kaplan-Meier-Methode zeigten, dass sowohl die rezidiv- und metastasenfreie als auch die Gesamtüberlebenszeit signifikant kürzer ist bei Patienten, deren Tumoren eine Amplifikation der chromosomalen Region 11q13 und/oder eine DNA-Überrepräsentierung des Chromsomarms 3q aufweisen (p=0,0008 bzw. p=0,0299 im Log-Rank-Test und p=0,0024 bzw. p=0,0546 im Breslow-Test). Die Cox-Regression wurde für das rezidiv- und metastasenfreie Überleben und für das Gesamtüberleben jeweils mit den klinisch-pathologischen Parametern pT-, pN-Status, UICC-Stadium, Grading und den genetischen Markern 11q13-Amplifikation sowie 3q-Überrepräsentierung durchgeführt. Die Analyse ergab die genetischen Veränderungen im Bereich von 11q13 und 3q als die wichtigsten Marker für die Einschätzung des Überlebens, während die klinisch-pathologische Tumorklassifikation ohne prognostischen Einfluss war (bei Signifikanzniveau p<0,05). Das Ergebnis unserer Studie eröffnet die Möglichkeit eines “genetischen Tumorgradings”, das als Zusatzinformation einer verbesserten Prognoseeinschätzung bei Kopf-Hals-Karzinomen dient.AbstractIn individual patients with head and neck squamous cell carcinomas (HNSCC), established prognostic factors do not satisfactorily predict clinical outcome. For the first time we investigated a total of 100 HNSCC by Comparative Genomic Hybridization (CGH) to define chromosomal alterations that are associated with the patients prognosis. Patients were followed for at latest 4 but at least 2 years after surgery or until death. During this observation period twenty-nine of them died because of cancer disease. The Kaplan-Meier method was used plotting survival curves for every single chromosomal alteration as well as every clinico-pathological parameter. The curves were tested for significance by the log rank as well as the Breslow test. Significance of particular prognostic parameters was then evaluated by the Cox regression model. The overall survival time as well as the recurrence free survival time were significantly lower in patients whos tumors showed amplifications of the chromosomal region 11q13 (p=0.0008 for LR and p=0.0024 for B). The survival time of the patients was also lower if the carcinomas carried overrepresentations of chromosome 3q (p=0.0299 for LR and p=0.0546 for B). Multivariate analysis (Coxs proportional hazards model) revealed both alterations as most important independent prognostic factors in HNSCC. None of the conventional clinico-pathological parameters (pT-, pN-status, UICC stage, grading) achieved statistical significance in the multivariate model. These results suggest that in HNSCC the occurence of 11q13 amplification and 3q overrepresentation are highly significant independent prognostic markers and of better value than the established TNM and grading criteria.

Human demineralised bone matrix as a bone substitute for reconstruction of cystic defects of the lower jaw

Ina retrospective study validated by a standardized clinical and radiologicalexamination, the bone regeneration in 90 patients with cystic mandibulardefectswas examined. In 50 patients bony defect reconstructions with humandemineralised bone matrix (HDBM) were carried out, while in a comparable groupof 40 patients the hollow pockets were left to regenerate bone spontaneously.The bone regeneration after the implantation of human demineralised bone matrix(HDBM) was subjected to a comparative validation. Osteoinductive proteinspresent in HDBM (bone morphogenetic proteins) can diffuse into the implant seatand induce new bone formation (osteoinduction). A markedly faster and morethorough bone regeneration was demonstrated after the surgical therapy ofcysticmandibular lesions with HDBM than without. HDBM also proved to be exceptionallybiocompatible.

Myocardial contrast echocardiography for predicting functional recovery after acute myocardial infarction.

Myocardial contrast echocardiography (MCE) is a promising diagnostic tool for detecting microvascular integrity. The aim of the study was to investigate the comparative specificity and sensitivity of intravenous MCE, technetium-99m Sestamibi single-photon emission computed tomography (SPECT) and dipyridamole–dobutamine (DIDO) stress echocardiography for predicting functional recovery after coronary revascularization in patients with acute myocardial infarction (AMI). Methods: In a prospective, observational study, 17 consecutive patients short after AMI who received successful treatment with primary percutaneous coronary angioplasty (PTCA) plus stent-implantation were examined with DIDO (dipyridamole with 0.28 mg/kg over 4 min plus dobutamine up to 10 mcg/kg/min), MCE (10 ml 4 g, 400 mg/ml Levovist® intravenously; second harmonic power imaging) within 12–24 h and resting perfusion SPECT within 48–72 h after PTCA. Functional recovery of regional contractile function after 6-month follow-up was the gold standard to assess viability. Results: The rate of agreement between SPECT and MCE was 69% and between SPECT and a positive response to stress echo was 76% for combined DIDO. MCE showed a higher sensitivity (96%) in the identification of viability than SPECT (77%) and combined DIDO alone (79%). Specificity was lower for viability recognition with MCE (58%) compared with SPECT (93%) and DIDO (87%). Conclusions: The wall motion response during DIDO echocardiography is useful in the prediction of recovery of regional and global ventricular function after revascularization in patients after AMI. Combined intravenous MCE and DIDO is more accurate in the diagnosis of stunned myocardium than Tc-99m-MIBI SPECT alone.

Der Sequentieile Quotiententest bei irreduziblen homogenen Markovschen Ketten mit endlichem Zustandsraum

The Sequential Probaility Ratio Test is applied to test two simple hypotheses about the transition probability matrix of an irreducible homogeneous MARKOV chain with finite state space. An analogue (14) of Walds Fundamental Identity, the Operating Characteristic Function (20-21) and the Average Sample Number (22-23) are given. These statements are generalizations of the MARKOV chain as well as some more conditions about the eigenvalues of the transition probability matrix.

Die waldsche fundamentalidentität und ein sequentieller quotiententest für eine zufäallige irrfahrtüber einer homogenen irreduziblen markovschen kette mit endlichem zustandsraum

For a random walk {R n ≥0} given on a homogeneous irreducible finite MARKOV chain {X n ≥0} the identity (8) is obtained. Generalizations (14)-(16) of WALDs Fundamental Identity and WALDs first and second equations for the two-dimensional process {(R n ,X n ), n≥0} are proved. The Average Sample Number (21)-(22) and the Operating Characteristic Function (24)-(25) of a Sequential Probability Ratio Test follow. With this test a decision about two simple hypotheses on the unknown transition probability matrix of {X n , n≥0} and the unknown parameters of the probability distributions for the increments of {X n , n≥0} can be made. For a special case these results were proved by PHATARFOD [6] and KuCHLER [3] with other methods.