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Biomedical subjects

P Hohenberger

Publications and source records attributed to P Hohenberger.

At least 19 recordsLinked to original sources
PubMed2007

Resection of soft tissue sarcoma of the lower limb after evaluation of vascular invasion with intraoperative intravascular ultrasonography.

BACKGROUND: This study investigated the value of intravascular ultrasonography (IVUS) in the intraoperative assessment of vascular invasion of soft tissue sarcoma. METHODS: In a 4-year interval, of 337 patients with soft tissue sarcoma, 20 patients with tumours of the lower limb in close relation to the neurovascular bundle underwent intraoperative IVUS (20 MHz). Intraoperative findings were correlated with preoperative imaging, histopathological appearance of the resection specimen and patient outcome. RESULTS: Intraoperative IVUS was technically successful in all 20 patients. It correctly predicted vascular involvement (true positive) in ten of 11 patients who required resection of major vessels. There was one false-negative and one false-positive result. With magnetic resonance imaging, there were ten true-positive and three false-positive scans, and one false-negative diagnosis. IVUS improved the assessment of vascular involvement in four of the 20 patients. Histopathological examination confirmed complete resection (R0) in 18 patients. Mean survival was 37 months, and no local recurrence was observed in these patients. CONCLUSION: Vascular infiltration by soft tissue sarcoma can be visualized accurately by IVUS. This may improve intraoperative decisions about vessel resection.

Adult↗
PubMed2006

[Surgical considerations for gastrointestinal stroma tumor].

Gastrointestinal stroma tumors (GIST), an abdominal stroma entity, are characterized by a gain-in-function mutation in the c-kit proto-oncogen (CD117). Initial treatment should aim at complete removal of the primary tumor (R0 resection), which almost never develops lymphatic metastases. Distant metastatic spread mainly involves the peritoneal cavity and the liver. In patients with metastatic disease, treatment with the tyrosine kinase inhibitor imatinib mesylate is indicated and very effective. Systemic chemotherapy and external beam radiation must be considered ineffective. Patients requiring multivisceral resection for primary tumor removal quickly develop tumor recurrence and could benefit from preoperative treatment with imatinib. To assess the response to treatment, 18F-FDG positron emission tomography or gadolinium-enhanced magnetic resonance imaging have proven helpful, as the conventional criteria of tumor shrinkage according to WHO standards are rarely met. Primary tumors are classified into four risk categories according to size and mitotic activity. The possible advantages of adjuvant treatment are currently under investigation through international randomized trials. Patients who develop extensive remission of metastatic disease should be evaluated individually for resection of the tumor remnants. Even the resection of single progressive lesions (newly developed mutations) should be considered in carefully selected patients if the remaining tumor can be controlled by continued imatinib treatment.

Antigens, CD34↗
PubMed2004

[Imaging modalities in the preoperative staging of rectal carcinoma].

Thorough clinical examination, endorectal ultrasound, and magnetic resonance tomography (MRI) are decisive tools in the pretherapeutic work-up of patients with rectal cancer. Depth of infiltration to the rectal wall as well as involvement of perirectal lymph nodes by the tumor are the key questions to be answered. To receive adequate information from imaging procedures, the right questions need to be asked. The extent of invasion of the rectal wall and exact location of tumor infiltration to neighboring structures can be demonstrated by MRI very well, particularly if imaging planes are acquired at 90 degrees to the position of the rectum. Recent developments in computed tomography (CT) using isotrope voxels allow three-dimensional reconstructions of tumors without loss of imaging quality. Assessment of the primary tumor and its nodal metastases after preoperative radio-(chemo-)therapy is still seriously limited. Fusion of positron emission tomography and CT could be a step towards solving the problem of response assessment in the near future.

Contrast Media↗
PubMed2004

[Current concepts and recent developments of laser ablation in tumor therapy].

PURPOSE: The purpose of this paper is to present technical innovations and clinical results of percutaneous interventional laser ablation of tumors using new techniques. METHODS; Laser ablation was performed in 182 patients (liver tumors: 131, non hepatic tumors-bone, lung, others: 51) after interdisciplinary consensus was obtained. The procedure was done using a combination of imaging modalities (CT/MRI, CT/US) or only closed high field MRI (1.5 T). All patients received an MRI-scan immediately after laser ablation. RESULTS: In 90.9% of the patients with liver tumors, a complete ablation was achieved. Major events occurred in 5.4%. The technical success rate of laser ablation in non-hepatic tumors was high, clinical results differed depending on the treated organ. CONCLUSIONS: The treatment of tumors of the liver and other organs up to 5 cm by laser ablation was a safe procedure with a low rate of complications and side effects. Image guidance by MRI is advantageous for precise tumor visualization in all dimensions, therapy monitoring, and control of laser ablation results.

Adult↗
PubMed2004

[Gastrointestinal stromal tumors (GIST)].

The vast majority of mesenchymal tumors originating from the GI tract consists of gastrointestinal stromal tumors (GIST), an entity just recently defined. The incidence is estimated to be around 10 - 20/1000000, the median age at diagnosis has been reported to be 55 to 65 years. GISTs most commonly occur in the stomach or duodenum, followed by the small intestine. About half of the patients present with metastatic disease at first diagnosis, predominantly in the liver or periteneum. GISTs are strongly and uniformly positive for CD117 (c-kit), a type III receptor-tyrosine kinase. Kit mutations, mostly in exon 11, leading to ligand independent constitutive activation are supposed to play a major role in the pathogenesis of GIST. Until recently no active systemic treatment was available for advanced gastrointestinal stromal tumors. Imatinib (STI571 = Glivec) is a rationally designed, orally available phenylaminopyrimidin analogue. The mechanism of action consists of a competitive interaction with the ATP-binding pocket of specific tyrosine kinases. Early results from clinical trials with response rates around 60 % and progression arrest in more than 80 % of patients resulting in fast relief of symptoms, confirm the high activity of this novel treatment. The role of adjuvant treatment after potentially curative resection of GIST is currently evaluated in ongoing clinical trials. Patients with progressive disease while under treatment with Imatinib should be enrolled in studies testing novel treatment strategies as RAD001, PKC412 or SU11 248.

Antineoplastic Agents↗
PubMed2004

Molecular response of gastrointestinal stromal tumour after treatment with tyrosine kinase inhibitor imatinib mesylate.

Bleeding from the tumour site is not uncommon during the treatment of gastrointestinal stromal tumours with imatinib mesylate. It might represent an early reaction of highly vascularised tumour tissue to receptor blockade. Although often requiring emergency surgery, this is not necessarily a deleterious sign. Slow tumour regression and cystic tissue alteration may follow. Using immunohistochemistry and consecutive resection specimens, it was shown that the number of mitoses decreased significantly and MIB-1 as a marker of cell proliferation could no longer be detected. In the few tumour cells still present, the magnitude of expression of the pathognomonic marker CD117 remained unchanged. Decreases in the size of tumours responding to imatinib mesylate cannot be expected to meet the World Health Organisation or RECIST (response evaluation criteria in solid tumours) criteria. This underlines the necessity of functional imaging by positron emission tomography, contrast enhanced magnetic resonance imaging, or magnetic resonance spectroscopy to assess the response to treatment.

Adult↗
PubMed2004

[Gastrointestinal stromal tumors carrying PDGFRalpha mutations occur preferentially in the stomach and exhibit an epithelioid or mixed phenotype].

AIMS: Most gastrointestinal stromal tumors (GISTs) carry gain-of-function mutations of the KIT gene encoding the receptor tyrosine kinase KIT. However, in a subset of GISTs no activating mutations are detectable in KIT. Recently, PDGFRalpha mutations have been identified as alternative oncogenic mechanism. We studied a panel of 100 GISTs for mutations in hot spot regions of KIT (exons 9, 11, 13 and 17) and PDGFRalpha (exons 12 and 18) and compared the results with pathomorphological and immunohistochemical data. METHODS: DNA from formalin-fixed and paraffin-embedded tumor tissue was extracted after microdissection from serial sections. We performed single strand conformational polymorphism analysis and direct sequencing. RESULTS: We found PDGFRalpha mutations in 24 of 55 GISTs with wild-type sequence in exons 9, 11, 13 and 17 of KIT. All mutations were located in exon 18 of the PDGFRca gene which encodes the tyrosine kinase domain II. None of the 45 GISTs with detectable KIT mutation carried a mutation in the PDGFRalpha gene. Interestingly, all PDGFRalpha-mutated tumors were located in the stomach whereas GISTs with exon 9 and 13 KIT mutations occurred predominantly in the small bowel. Additionally, 21 of 24 GISTs carrying PDGFRalpha mutations displayed an epithelioid or mixed phenotype. In contrast, KIT-mutated GISTs exhibited almost always a spindled histology (38 of 45 cases). CONCLUSIONS: Our analysis provides evidence that GISTS represent distinctive entities with different genetic, biological and phenotypic features.

Diagnosis, Differential↗
PubMed2003

[Synovial sarcoma of the extremities. Results of surgical and multimodal therapy].

BACKGROUND: Synovial sarcoma is a rare tumor frequently occurring in adolescents and young adults. The preferred location, at the distal parts of the extremities, and the high incidence of distant metastases represent major challenges for treatment. The purpose of this study is to analyze the indications for surgery in the context of a multimodal therapy. PATIENTS AND METHODS: Between October 1992 and December 2000, 41 patients were treated surgically for synovial sarcoma of the extremities. Their mean age was 35 years (range: 11-75 years). Extracompartmental tumor growth was present in more than 90% of the patients. Fourteen patients (34%) presented with a tumor size of less than 5 cm (T1) while 27 patients (66%) showed lesions greater than 5 cm (T2). At the time of presentation, seven patients had distant metastases; three located in the lung and four in lymph nodes. RESULTS: Due to a locally unresectable tumor or synchronous distant metastases, 28 patients (68%) underwent preoperative systemic chemotherapy (n=9) or isolated limb perfusion (n=18) or both (n=1). In 29 patients, limb-conserving surgery was possible. Of the 12 patients (29%) who required amputation, 85% had a distal tumor. Sixteen patients received additional postoperative radio- and/or chemotherapy. After a median follow-up of 30 months, only two patients (7%) had developed a local recurrence, while seven patients (20%) suffered from new, distant metastases. The 5-year overall survival rate was 82%. CONCLUSION: With a combined modality treatment, it is possible to achieve excellent local control rates and long-term survival in patients with synovial sarcoma of the extremities. Neoadjuvant treatment can enable limb-sparing surgery in most patients, even if the tumors are located in anatomically difficult areas.

Adolescent↗
PubMed2003

Outcome analysis of 189 consecutive cancer patients referred to the intensive care unit as emergencies during a 2-year period.

The referral of critically ill cancer patients to an intensive care unit (ICU) is a matter of controversial debate. This study was conducted by an interdisciplinary clinical group to evaluate the outcome of ICU treatment in cancer patients according to their characteristics at the time of referral. A retrospective analysis was used to identify relevant subgroups among 189 consecutive cancer patients referred as emergencies to one of four ICUs during a 2-year period. Reasons for ICU referral were pneumonia (29.6%), sepsis (27.0%), fungal infection (11.1%), another infection (9.5%), gastrointestinal emergency (16.9%), treatment-related organ toxicity (6.9%), or other, non-infectious complications (43.9%). Vasopressor support was required in 50.3%, mechanical ventilation in 49.7%, and haemodialysis/-filtration in 26.5% of the patients. Overall, 41.3% died during ICU treatment, 12.2% died after transfer from ICU to a non-ICU ward, and 35.4% were discharged alive. Sepsis, mechanical ventilation, vasopressor support, renal replacement therapy and neutropenia were independent risk factors for fatal outcome, but no single risk factor unequivocally predicted death. All patients with fungal infection who required vasopressor support and either had sepsis (n=13) or needed mechanical ventilation (n=14) died during ICU treatment, while all non-septic patients. who did not require mechanical ventilation, were younger than 74 years of age and had a non-infectious underlying complication (n=29), survived. This analysis may help to early identify relevant subgroups of cancer patients with different prognoses under ICU treatment. A prospective study to confirm the predictive usefulness of this approach is needed. Cancer patients should not be excluded from referral to the intensive care unit in an emergency solely due to their underlying malignant disease or a single unfavourable prognostic factor.

Adult↗
PubMed2003

[Morphology of gastrointestinal stromal tumors in advanced stages of the disease: baseline findings before chemotherapy with imatinib].

PURPOSE: Gastrointestinal stromal tumors (GISTs) are rare tumors of the gastrointestinal tract with an increasing detection rate due to improved differentiating methods in current diagnostic pathology. This study evaluates the radiologic characteristics of these neoplasms to discover specific signs leading to an earlier diagnosis. MATERIALS AND METHODS: As part of a randomized phase III clinical trial of the European Organization for Research and Treatment of Cancer (EORTC), 72 patients with advanced stage GIST were treated with the selective tyrosine-kinase-inhibitor imatinib (Glivec, Novartis, Switzerland). For initial staging, 60 patients underwent MRI and 12 patients underwent CT. RESULTS: GISTs are mesenchymal tumors that grow submucosally and exophytically and become multiple, nodular or ovoid in the advanced stage. The predominant findings are peripheral solid structures with strong contrast enhancement and a central necrosis. Metastases are primarily located in the liver, where they appear as oval or round, sharply delineated solitary lesions with central necrosis. CT demonstrates the primary tumors and local recurrences as nearly isodense with the liver. On MRI, the lesions are hypointense on T 1 -weighted sequences and hyperintense on T 2 -weighted sequences, compared to the liver. CONCLUSION: Immunopathology now enables the exact histologic separation of GISTs from other mesenchymal tumors. The radiological morphology is not sufficiently specific to differentiate GISTs from other mesenchymal tumors. In view of new therapeutic options, cognizance of their typical manifestations is of increasing importance for radiologists.

Adult↗
PubMed2003

[Use of SPIO-enhanced T1- and T2-weighted images for the differentiation of liver lesions: an ROC analysis].

PURPOSE: The superparamagnetic iron oxide (SPIO) Resovist is a contrast media with shortening of both T(1) and T(2) relaxation time. This study evaluates the impact of SPIO-enhanced T(1)- and T(2)-weighted images for the differentiation of liver lesions. MATERIALS AND METHODS: SPIO-enhanced MRI examinations (1.5 T, Symphony Quantum) of 61 patients were analyzed. Thirty-seven patients had malignant liver lesions (metastases n = 32, HCC n = 5) proven by biopsy or laparotomy, 11 patients had benign liver lesions (FNH n = 2, hemangiomas n = 4, benign cysts n = 5, normal liver on laparoscopy n = 13). After unenhanced T(1)- and T (2)-weighted imaging, a bolus injection of 1.4 ml SPIO (Resovist) was given, followed by T(1)-weighted imaging at 20 s, 60 s, and 5 min and T(2)-weighted imaging at 10 min post injection. A score from 1 (benign) to 5 (malignant) was used by three blinded radiologist for the ROC analysis of the unenhanced T(1)-/T(2)-weighted images (set 1) and of the combinations of unenhanced T(1)/T(2)-weighted and SPIO T(1)-weighted images (set 2), unenhanced T(1)/T(2) and SPIO T(2)-w images (set 3) and all images (set 4). RESULTS: The accuracy of plain MRI (set 1: 56 %) was increased by SPIO-enhanced T(1)-weighted images (set 2: 81 %) and SPIO-enhanced T(2)-weighted images (set 3: 90 %). Best results were obtained using unenhanced T(1)-weighted, unenhanced T(2)-weighted and both SPIO T(1)-weighted and T(2)-weighted images (set 4: 93%). The accuracy of predicting histopathologic diagnosis was 91%. CONCLUSION: For the differentiation of liver lesions, SPIO-enhanced T(2)-weighted images had a greater impact on the accuracy of MRI than T (1)-weighted images, but SPIO-enhanced T(1)-weighted images provided additional information in some patients and should not be deleted.

Adult↗
PubMed2002

[Aneurysm of the popliteal vein causing pulmonary thromboembolism that required resuscitation].

HISTORY AND ADMISSION FINDINGS: A previously healthy 40-year-old varnisher was admitted because of increasing dyspnoea. His clinical status rapidly deteriorated. He was referred to a cardiology intensive care unit but had to be resuscitated during transport. His condition became stable under controlled ventilation and analgesics. There were no other contributory abnormal findings. INVESTIGATIONS: The concentration of D-dimers was raised. Pulmonary angiography demonstrated multiple bilateral occlusions of the segmental arteries. TREATMENT AND COURSE: Extubation became possible after thrombolysis with recombinant tissue plasminogen activator (rTPA). There was no evidence of leg or pelvic vein thrombosis. But a hard mass was palpated in the left popliteal fossa and extensively thrombosed saccular aneurysm of the popliteal vein was found. The aneurysm was resected and a venous graft was interposed. There were no further thromboemboli under oral anticoagulation. Two years later the venous graft was occluded with adequate collateral circulation. CONCLUSION: Aneurysm of the popliteal vein is a rare vascular anomaly of unknown pathogenesis. In patients with repetitive episodes of lung embolism peripheral aneurysms must be taken into consideration.

Adult↗
PubMed2002

[T4 rectal carcinoma. Surgical and multimodal therapy].

BACKGROUND: In locally advanced rectal cancer with infiltration of neighbouring organs (uT4), resectability and local control are difficult to achieve. Combined preoperative radiochemotherapy may result in increased resectability and reduced local recurrence rates. PATIENTS AND METHODS: Thirty-four patients with biopsy-proven locally advanced rectal cancer were treated by preoperative radiochemotherapy. All tumours had been staged as uT4 lesions by endorectal ultrasound or computed tomography. Radiotherapy was applied in standard blocks, 5 x 1.8 Gy up to 45 Gy. Chemotherapy consisted of two cycles of 5-fluorouracil (300-350 mg/m2/day) and leucovorin (50 mg). In 20 patients, additional thermotherapy was carried out using the Sigma 60 applicator BSD 2000 once a week prior to radiotherapy. Surgery was performed 4-6 weeks after radiochemotherapy. Postoperatively, all patients received four cycles of 5-fluorouracil and leucovorin. RESULTS: Treatment-induced toxicity occurred in 26% of the patients (WHO grade III (n = 6) and IV (n = 3)). The resectability rate was 76% (26/34 patients) (R0 resectability n = 21; 62%). The pathological complete response rate was 6% (n = 2) and the partial response rate was 47% (n = 16). A local failure was observed in six patients after median time of 16 months (range 7-36 months). Patients with R0 resection achieved a 5-year disease-free survival rate of 55% and a survival rate of 71%. The overall 5-year survival rate for all patients with advanced uT4 rectal cancer was 49%. CONCLUSIONS: Our data on preoperative combined treatment in locally advanced T4 rectal cancer revealed encouraging downstaging, local control, and survival rates.

Adult↗
PubMed2001

[Value of laparoscopic ultrasound for staging of gastrointestinal tumors].

BACKGROUND: The objective of this study was to evaluate the impact of laparoscopic ultrasound on the staging of gastrointestinal tumors prospectively. METHODS: Between 1993 and 2000 staging laparoscopy was performed on 668 patients with various neoplasms. Laparoscopy provided adequate information regarding resectability in 366 patients. Laparoscopic ultrasonography was performed in 302 patients (45%) using an intraoperative ultrasound unit (B & K) and a semiflexible ultrasound probe (5-7.5 MHz). The results of staging laparoscopy were compared to the preoperative staging and histopathology. RESULTS: Compared to preoperative staging laparoscopic ultrasound provided additional information of therapeutic relevance in 46 of 302 cases (15%). In a group of 384 patients with tumors of the upper gastrointestinal tract, laparoscopic ultrasound was performed in 186 cases and showed occult liver metastases, M1-lymph nodes, or nonresectable disease in 26 patients. Overall, this technique improved the staging of esophageal, gastric and pancreatic cancer in 12%, 3%, and 12% of the patients, respectively. Laparoscopic ultrasound proved to be most useful in esophageal and pancreatic cancer with a rate of 52% and 20% information additional to laparoscopy. The relative contribution of laparoscopic ultrasound to the staging of gastric cancer was only 10%. CONCLUSION: Laparoscopic ultrasound improves the diagnostic accuracy of staging laparoscopy. However, routine use of this technique is only justified, if neoadjuvant therapy--particularly in controlled trials--is considered in patients with advanced gastrointestinal cancer.

Carcinoma, Squamous Cell↗
PubMed2001

Three-dimensional ultrasonography of bone and soft tissue lesions.

BACKGROUND: The aim of this study was to investigate feasibility and potential applications of three-dimensional (3D) ultrasonography in the evaluation of musculoskeletal disorders. METHODS: 3D ultrasonography was performed in 83 patients with bone (n = 50) or soft tissue lesions (n = 33). Volume data were obtained using two volume probes (1-8.5 and 8.5-12 MHz) and a 3D ultrasound unit. The results of 3D ultrasonography were compared to two-dimensional ultrasound and radiological imaging. RESULTS: The system enabled acquisition of 3D ultrasound data in diagnostic quality. 3D image-processing permits to analyse ultrasound data interactively in three orthogonal planes (section mode) or in realistic 3D views (rendering mode). Compared to conventional ultrasonography 3D image analysis improved assessment of details, provided better spatial orientation and facilitated image interpretation in 23, 44 and 49 cases, respectively. Additional findings that had significant influence on patient management were obtained in 16 of 83 patients (19%). Multiplanar reformating provided additional scan planes and increased the comparability of follow up examinations by standardized display and measurement. 3D surface reconstructions were very helpful to understand the morphology of bone lesions e.g. tortuous fracture lines. CONCLUSION: Our preliminary experience shows that 3D ultrasonography of musculoskeletal disorders is feasible. The ability to assess previously unattainable scan planes and lifelike surface projections may be particularly valuable for imaging of bone lesions. Further studies will be required to assess the exact role of this new technique for the evaluation of musculoskeletal disorders.

Adult↗