[Gross tumor volume (GTV) and clinical target volume (CTV) in radiotherapy of benign skull base tumors].
Skull base tumours represent about 35 to 40% of all intracranial tumours. There are now many reports in the literature confirming the fact that about 80 to 90% of such tumours are controlled with fractionated radiotherapy. Stereotactic and 3-dimensional treatment planning techniques increase local control and central nervous system tolerance. Definition of the gross tumor volume (GTV) is generally easy with currently available medical imaging systems and computers for 3-dimensional dosimetry. The definition of the clinical target volume (CTV) is more difficult to appreciate; it is defined from the CTV plus a margin, which depends on the histology and anterior therapeutic history of the tumour. It is important to take into account the visible tumour and its possible extension pathways (adjacent bone, holes at the base of skull) and/or an anatomic region (sella turcica + adjacent cavernous sinus). It is necessary to evaluate these volumes with CT Scan and MRI to appreciate tumor extension in a 3-dimentional approach, in order to reduce the risk of marginal recurrences. The aim of this paper is to discuss volume definition as a function of tumour site and tumour type to be irradiated.
Maire
J P
JP
Service d'oncologie-radiothérapie, CHU de Bordeaux, hôpital Saint-André, 1, rue Jean-Burguet, 33075 Bordeaux, France. jean-philippe.maire@chu-bordeaux.fr
Liguoro
D
D
San Galli
F
F
D006801:Humans; D008279:Magnetic Resonance Imaging; D010347:Patient Care Planning; D020266:Radiotherapy, Conformal / Q000379:methods*; D019292:Skull Base Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D013238:Stereotaxic Techniques; D014057:Tomography, X-Ray Computed