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Radiation treatment decisions in patients with prostate cancer and suspected lymph node metastasis based on USPIO-MRI
For the second in his series of articles for European Hospital, Professor Stefan Schönberg of the Institute of Clinical Radiology and Nuclear Medicine (IKRN), University Hospital Mannheim, Medical Faculty Mannheim, University of Heidelberg, invited colleagues from the Nijmegen University Medical Centre (UMC St Radboud) for a roundtable discussion on:
Prostate cancer is the most frequent cancer in men with about 49,000 newly diagnosed cancers in Germany and 6,000 in the Netherlands, annually.
Professor Stefan Schönberg
Meet the experts
D.J. Dinter1, J.O. Barentsz3, F. Lohr2, E.N. van Lin4, A.M. Weidner1,
T. Hambrock3, N. Schnitzer1,
F. Wenz2, S.O. Schönberg1
1 Department of Clinical Radiology and Nuclear Medicine, University Hospital Mannheim, Medical Faculty Mannheim, University of Heidelberg, Germany
2 Department of Radiation Oncology, University Hospital Mannheim, Medical Faculty Mannheim, University of Heidelberg, Germany
3 Department of Radiology, University Medical Centre Nijmegen, The Netherlands
4 Department of Radiation Oncology, University Medical Centre Nijmegen, The Netherlands
Recently, diagnostic imaging techniques have become available which enable improved lymph node staging. At present, the most accurate method is MR lymphography with ultra-small super paramagnetic iron oxide particles (USPIO, Sinerem). Using a 3T scanner, metastases in nodes measuring 2-3 mm can be detected. Up to now no serious side-effects have been reported. Regrettably, this promising technique, using Sinerem contrast, is not yet commercially available.
Currently, the extension of radiation fields depends on the risk for lymph node metastasis. This risk is calculated according to the Roach formula. Patients at low risk (<15%) undergo irradiation of the prostate only, whereas patients with high risk (>15%) may benefit from radiation of the whole pelvis, including the lymph nodes. Moreover, it has been demonstrated that radiation therapy is more effective at a higher dose. This requires an exact delineation of both tumour and metastases. Following this, improved radiation techniques, like intensity-modulated radiation therapy (IMRT), are needed for patients to benefit from the advanced imaging. In a new concept, the ‘dominant intraprostatic lesion’ (DIL) is irradiated with a higher dose than the rest of the prostate. A similar procedure is planned for the concept of ‘MR guided lymph node IMRT’ (MGL-IMRT).
A: T2-weighted axial image of the prostate. In the right central and peripheral zone a hypo-intense area is visualised, a prostate cancer with extracapsular extension.
B: ADC-map calculated from the diffusion-weighted images showing restriction in the Brownian movement of water molecules within the cancerous area.
C: Parametric map of plasma flow, determined from dynamic contrast enhanced T1 images, obtained after bolus injection of a Gadolinium-based contrast agent. The tumour shows an increased plasma flow.
D: Metabolic map of a chemical shift spectroscopy image showing an increased Choline/Citrate ratio in the central area of the prostate cancer tissue.
In this way the potential of improved prostate imaging to enable a more effective therapy will be optimally explored. As a consequence of this, it is envisioned that disease-free survival of patients with prostate cancer can be prolonged and side-effects and costs caused by not stage adapted treatment can be reduced.
Additionally, we would like to invite you to the newly established transatlantic meeting ACSI, which will take place on 20-21 June 2008 in Mannheim, Germany.
Details: www.mr-pet-ct.com
This article was published on 04/30/2008