Marieke van Son

51 MRI-GUIDED ULTRAFOCAL HDR-BRACHYTHERAPY QoL Supplementary figures 1-3 (available online at https://doi.org/10.1016/j. ijrobp.2019.03.032) give an overview of RAND-36, EORTC QLQ-C30 and PR-25 ques- tionnaire scores. Within the RAND-36 domains, clinically relevant decrease was seen in social functioning (>10 points after 1 and 24 months), vitality (10 points after 9 months) and pain (>10 points after 1 month). All scores returned to baseline value. Mental and general health showed no increase >10 points, contrary to our previous report(7). No significant differences at the 0.001 level were seen. The QLQ-C30 showed clinically relevant deterioration in the domains for tiredness (>10 points after 48 months) and sleeping disturbances (only at 24 months). On the contrary, improvement was seen in the domains for emotional functioning (>10 points after 48 months) and cognitive functioning (>10 points after 36 months). There were no statistically significant differences from baseline. Within the PR-25, urinary symptoms increased from 10 at baseline to 17 in the first month, after which scores recovered to baseline. Bowel symptoms remained stable at 0. Treatment-related symptoms went from 0 at baseline to a score of 6 at all follow-up time points. A clinically relevant decrease of >10 points was seen in sexual activity at all follow-up times. Sexual functioning, on the contrary, remained relatively stable. Again, there were no statistically significant differences. Tumour control Ten patients experienced BF, with local prostatic recurrence in 9 patients on PET/CT (18F-Choline [n=1] and later 68Ga-prostate specific membrane antigen [PSMA] [n=9], both in combination with mp-MRI). Of all intraprostatic recurrences, 7/9 were out-of- field lesions with respect to the primary tumour. Comparing the original CTVs of the primary HDR-procedure to the recurrent lesions on PSMA PET-CT, most (5/7) were located on the contralateral prostate lobe. Two patients had a recurrence in the same lobe, but with a distinct distance between primary and recurrent lesion sites. Three patients had local and metastatic disease. Two were referred to their urolo- gist for deferred ADT. One patient underwent stereotactic body radiotherapy (SBRT, 1x18Gy) twice to different solitary bone metastases, before receiving whole-gland sal- vage Iodine-125 brachytherapy. One year later, PSA-levels rose again after which ADT was initiated. Of 6 patients with solitary localized recurrence, 4 received local salvage: either ultra- focal salvage HDR-brachytherapy (n=2) or whole-gland salvage Iodine-125 brachyther- apy (n=2). Until now, PSA-levels remain low in all re-treated patients between 1- and 3-years follow-up. The remaining 2 patients requested an active surveillance strategy. One patient with BF presented with a solitary metastasis in L4 without local prostatic recurrence, for which he received SBRT (1x18Gy). Unfortunately, there was no PSA-re- sponse and he subsequently received ADT. 3