Postprostatectomy ultrasound-guided transrectal implantation of gold markers for external beam radiotherapy
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enhuijsen1 · R. Donker3 · G.M. McColl2 · L.A.L.M. Kiemeney1 · J.A. Witjes1 · E.N.J.T. van Lin2 1 Department of Urology, Radboud University Nijmegen Medical Center, Nijmegen 2 Department of Radiation Oncology, Radboud University Nijmegen Medical Center, Nijmegen 3 Department of Radiation Oncology, Medical Center Alkmaar, Alkmaar
Postprostatectomy ultrasound-guided transrectal implantation of gold markers for external beam radiotherapy Technique and complications rate
The implantation of intraprostatic gold markers for external beam radiotherapy (EBRT) of prostate cancer has become a standard technique for daily position verification and correction of patient setup errors and prostate motion [1, 2]. Gold markers also represent a valuable tool to ensure setup accuracy of image-guided high-dose rate (HDR) brachytherapy [3]. Long-term experiences with gold marker implantation have been reported recently [4] and complication rates were shown to be low [5]. Improved biochemical control rates were found with dose-escalation [6, 7]. However, with increased doses, both delineation of the target volume and high-precision dose delivery are important to prevent increased toxicity to the surrounding organs [8]. Radiation therapy (RT) after radical prostatectomy offers an overall and biochemical relapse-free survival benefit when applied in adjuvant and salvage settings [9, 10, 11, 12]. In contrast to published data on prostate motion [13, 14, 15, 16], data on patient setup uncertainties and prostate bed motion during postprostatectomy RT are sparse [17, 18, 19, 20]. To our knowledge, the use of gold markers in this setting has been described just three times [19, 20, 21]. According to Ost et al. [22], prostate bed motion is similar to that of the intact prostate gland. The prostate bed is invaded by the rectal wall and rec-
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Strahlentherapie und Onkologie 6 · 2013
tal filling leads to a change in prostate bed shape. Daily electronic portal imaging of gold markers may be a valuable method to correct for interfraction target motions and thus improve precision during EBRT delivery [19]. The correction of target positioning errors is especially critical when small, prostate bed-only fields are irradiated. Small shifts in target volume have the potential to significantly alter the distribution of the dose delivered to adjacent organs. The side effects of postprostatectomy gold marker implantation may differ from those arising after their implantation in the highly vascularized prostate gland. Theoretically, less bleeding may occur. However, anatomic changes may prevent recognition of the implantation site and make the procedure technically more challenging. The anastomosis site is located distally in the pelvis, which may lead to misplacement of markers or pain during implantation. Fibrosis around the bladder/urethra anastomosis may render pain more prominent. The aim of this study was to evaluate the technique and complications rate of postprostatectomy transrectal implantation of gold markers, as well as to analyze poten
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