1 General Aspects

16 General Aspects

precise measurement (in mm) and of course all the tools offered by modern imaging. (20) With this combination, the safety margin between the dose needed to sterilise the tumour, and the dose which will produce a necrosis of normal tissue is very narrow. In certain circumstances, there is no safety margin and one should accept a calculated risk of late complications in order to cure the tumour. 7.3.2 Combination with surgery A perioperative implant can be indicated when the surgeon can remove most of the tumour, but is unable to guarantee a safety margin in one part of the tumour bed. If this area of possible remaining cancer cells can be precisely described and is easily accessible, it is the best indication for intraoperative brachytherapy. A removable implant using the plastic tube technique is always preferable to achieve postoperative afterloading. In some deep situated tumours, only a permanent implant is possible, with intraoperative loading. 7.3.3 Combination with chemotherapy Chemotherapy, more often combined with external beam radiotherapy, can be used in T3 cancers before brachytherapy implantation. Initially enormous tumours can thus be shrunk to permit implantation. As in the combination with external radiation, the initial infiltrating tumour volume should always be considered, whatever the shrinkage of the tumour. The indications for brachytherapy are summarised in Table 1.1 (see overleaf), according to different tumour sites, depending on the tumour size, according to the dose rate to be used, and to the afterloading system to be chosen in case of temporary or permanent implant. These different choices are only given as proposed indications and must be discussed according to the therapeutic protocols, to the possibilities of treatment combinations and of course to the technical possibilities and experience of each treatment centre. (11,13,14,18,26,29,30,34)