External validation of a model to predict the survival of patients presenting with a spinal epidural metastasis

The surgical treatment of spinal metastases is evolving. The major problem is the selection of patients who may benefit from surgical treatment. One of the criteria is an expected survival of at least 3 months. A prediction model has been previously developed. The present study has been performed in order to validate externally the model and to demonstrate that this model can be generalized to other institutions and other countries than the Netherlands. Data of 356 patients from five centers in Germany, Spain, Sweden, and the Netherlands who were treated for metastatic epidural spinal cord compression were collected. Hazard ratios in the test population corresponded with those of the developmental population. However, the observed and the expected survival were different. Analysis revealed that the baseline hazard function was significantly different. This tempted us to combine the data and develop a new prediction model. Estimating iteratively, a baseline hazard was composed. An adapted prediction model is presented. External validation of a prediction model revealed a difference in expected survival, although the relative contribution of the specific hazard ratios was the same as in the developmental population. This study emphasized the need to check the baseline hazard function in external validation. A new model has been developed using an estimated baseline hazar

Clinicopathological features and risk factors for developing colorectal neoplasia in Hodgkin's lymphoma survivors

Background Hodgkin's lymphoma (HL) survivors treated with abdominal radiotherapy and/or procarbazine have an increased risk of developing colorectal neoplasia.Aims We evaluated the clinicopathological characteristics and risk factors for developing (advanced) neoplasia (AN) in HL survivors.Methods In all, 101 HL survivors (median age 51 years, median age of HL diagnosis 25 years) underwent colonoscopy and 350 neoplasia and 44 AN (classified as advanced adenomas/serrated lesions or colorectal cancer), mostly right-sided, were detected, as published previously. An average-risk asymptomatic cohort who underwent screening colonoscopy were controls (median age 60 years). Clinicopathological characteristics of AN were evaluated in both groups. Mismatch repair (MMR) status was assessed using immunohistochemistry (MLH1/MSH2/MSH6/PMS2). Logistic regression analysis was performed to evaluate the risk factors for AN in HL survivors, including age at HL diagnosis and interval between HL and colonoscopy.Results In 101 colonoscopies in HL survivors, AN was primarily classified based on polyp size >= 10 mm, whereas (high-grade)dysplasia was more often seen in AN in controls. An interval between HL diagnosis and colonoscopy >26 years was associated with more AN compared with an interval of = 10 mm) in HL survivors. Longer follow-up between HL diagnosis and colonoscopy was associated with a higher prevalence of AN in HL survivors.Cellular mechanisms in basic and clinical gastroenterology and hepatolog

De tijdsfactor bij een bestralingsbehandeling

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Radiobiological studies of glial stem cells

Contains fulltext : mmubn000001_167202472.pdf (publisher's version ) (Open Access)Promotores : A. van der Kogel en W. van Daal155 p

Chemotherapy and radiotherapy in Hodgkin's lymphoma: joining in or splitting up?

Contains fulltext : 51336.pdf (publisher's version ) (Closed access)PURPOSE OF REVIEW: Radiotherapy is very effective in local control of Hodgkin's lymphoma. Unfortunately, long-term survivors exhibit an excess of life-threatening radiation-related late side effects. Consequently, there have been calls to cease the use of radiation in the primary treatment of Hodgkin's lymphoma, although there is also support for the judicious use of combined modality treatment. RECENT FINDINGS: Most patients treated for Hodgkin's lymphoma are being cured with modern approaches. Recent publications confirm the superior efficacy of combined modality treatment over chemotherapy alone, but the initial gain in cure rate may be outweighed by late deaths due to various treatment-related diseases.Many patients may already be cured by chemotherapy alone. Classical risk factors can be used to distinguish favourable and unfavourable subgroups of patients with Hodgkin's lymphoma, but these risk factors cannot predict outcome in individual cases. A simple test to predict the likelihood of cure in individual patients would be of great benefit. Fluoro-deoxyglucose-PET scan investigation holds this promise. SUMMARY: The present review deals with the role of radiation therapy in the treatment of Hodgkin's lymphoma

Hodgkin's lymphoma: news from an old disease.

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Role of radiotherapy in the treatment of lymphomas of the gastrointestinal tract.

Contains fulltext : 89355.pdf (publisher's version ) (Closed access)In patients with gastrointestinal lymphoma the most frequently involved site is the stomach (60%-75% of cases), followed by the small bowel, ileum, cecum, colon and rectum. The most common histological subtypes are extranodal marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT) and diffuse large B-cell lymphoma (DLBCL). The role of radiotherapy is most definite in early stage gastric lymphoma. The therapeutic approach for patients with gastric Non Hodgkin lymphoma (NHL) has changed significantly over the last decades. The primary treatment of limited gastric MALT lymphoma consists of Helicobacter pylori eradication. In case of insufficient response to H. pylori eradication or in case H. pylori is absent, irradiation of the stomach and perigastric lymph nodes to a dose of 30-40Gy in 15-20 fractions is indicated. In patients with gastric DLBCL conservative treatment with anthracycline-based chemotherapy alone or in combination with involved-field radiotherapy has become the therapy of choice.1 februari 201

Conformal photon-beam radiotherapy of prostate carcinoma.

Three-dimensional conformal radiotherapy is the recommended radiation technique for localized or locally advanced prostate cancer. In the past decades, external beam irradiation procedures have evolved in the context of technical developments of radiation and imaging equipment. The article summarizes these developments and gives a definition of new techniques and their potential advantages over conventional irradiation. It is meant to provide urologists and medical and radiation oncologists with a better comprehension of modern radiation treatment of prostate cancer and its possible improvements in the future

Visual acuity and scar size in eyes with age-related subfoveal choroidal neovascular lesions, 30 months after radiation therapy

Contains fulltext : 23346___.PDF (publisher's version ) (Open Access

Radiotherapy with carbogen breathing and nicotinamide in head and neck cancer: feasibility and toxicity

Contains fulltext : 20985___.PDF (publisher's version ) (Open Access