Marieke van Son

172 CHAPTER 9 are promising and major complications in the future are not expected due to the high level of dose control with respect to the OAR. The combination of MRI guidance and the steep dose fall-off in brachytherapy allows for high precision in administering the radiation dose to the tumor. In the described case, dose constraints for the OAR were not exceeded during both focal HDR-BT treatments. Within the literature, there are few papers covering repeat salvage therapy. One case report by Claren et al. on second salvage treatment using whole-gland HDR-BT (5x7Gy) showed limited toxicity (grade 2 urinary incontinence). After 24 months, a PSA nadir of 0.03 ng/ml was reached [8]. More recently, Maenhout et al. described a case series of four patients receiving MRI-guided focal salvage HDR-BT after previous salvage I-125 brachytherapy. No postoperative development of grade ≥2 toxicity was observed. Lymph node metastatic disease was detected in one patient during follow-up [9]. Choosing the appropriate salvage treatment strategy for recurrent prostate cancer is a complex matter and patient selection for focal treatment depends on many factors. To estimate the risk of toxicity, it is essential to establish any pre-existing urinary or bowel symptoms. Time from treatment to biochemical relapse and PSA kinetics, such as PSADT, have prognostic relevance with respect to salvage oncologic outcomes [10]. Appropriate imaging modalities should be deployed for accurate tumor staging and the detection of disseminated disease. We have adopted 68Ga-PSMA PET-CT and mp-MRI as standard imaging techniques. From our experience, the diagnostic accuracy of this imaging combination has rendered prostate biopsies unnecessary since image-guided biopsies were all tumor-positive in the past. In the salvage setting, the assessment of in- or outfield recurrence is important because infield recurrences with a short interval from the previous treatment (less than two years) may indicate radioresistancy and are, therefore, less susceptible to repeat focal salvage irradiation. CONCLUSIONS MRI-guided focal salvage HDR-BT is a novel modality within the range of local treat- ment options for recurrent prostate cancer. This case report highlights the potential of this therapy with regard to re-treating locally recurrent prostate cancer after previous salvage treatment. Re-salvage could further delay or even avoid the need for ADT, there- by minimizing the risk of exposure to hormone-related toxicity. The joint use of MRI guidance and HDR-BT allows for targeted therapy with minimal risk of toxicity. There- fore, focal re-treatment seems possible. Further experience in treating patients with re-recurrent local prostate cancer will yield more knowledge on long-term outcomes.