Marieke van Son

113 QOL AFTER ULTRAFOCAL SALVAGE HDR-BRACHYTHERAPY An explorative assessment of potential predictors for HR-QoL change was performed for the domains urinary symptoms and sexual functioning, as these domains showed clini- cally relevant change over time (Table 2). Higher (i.e. worse) baseline HR-QoL score and higher administered dose to the urethra were significant predictors for urinary symp- toms. A post-hoc cut-off analysis revealed that a constraint of 16 Gy was the lowest value at which urethra D10% was a significant predictor in the model. Higher (i.e. better) baseline HR-QoL score (p<0.01) was predictive of better sexual functioning over time. Table 2 – Association of predictors with HR-QoL change per affected domain Domain 95% CI β lower upper p-value Urinary symptoms Administered dose to the urethra Administered dose to the bladder Baseline HR-QoL score Age Size of the CTV (cc) Tumor stage on MRI >T2 0.62 -0.47 0.73 -0.03 -0.09 3.76 0.19 -1.03 0.59 -0.35 -0.36 -0.74 1.06 0.09 0.87 0.28 0.18 8.78 <0.01 0.10 <0.01 0.83 0.52 0.20 Sexual functioning Previous use of ADT* Baseline HR-QoL score Age Size of the CTV (cc) Tumor stage on MRI >T2 Dorsolateral location of the tumor 7.15 0.68 -0.26 0.05 -5.17 5.09 -1.20 0.48 -0.90 -0.34 -12.22 -2.86 15.50 0.88 0.37 0.44 1.88 13.04 0.07 <0.01 0.42 0.81 0.15 0.21 Legend: HR-QoL: health-related quality of life, CTV: clinical tumor volume, ADT: androgen deprivation therapy, β: estimate of the effect, 95% CI: 95% confidence interval. *Aspartofprimary treatment (neo-adjuvant or adjuvant). A more detailed view on individual HR-QoL items is provided in Supplementary Table 1, with separate item scoring patterns. The table displays the percentage of patients reporting any symptom (score>1) at each follow-up time point. Most reported urinary symptoms in the first month after treatment were dysuria, urgency, difficulty leaving the house and being limited in daily activities. Incontinence was also frequently reported, with a maximum of 14 patients declaring the need to wear an incontinence aid. Sexual functioning was mainly impaired by erectile dysfunction, ejaculation problems and sexual intimacy issues. DISCUSSION This study shows that ultrafocal salvage HDR-BT has limited effect on patient-reported bowel function and sexual activity but causes a (temporary) increase in urinary symp- toms and a decrease of sexual functioning over time. Predictive factors for deterioration of urinary HR-QoL are increased urinary symptoms at baseline and higher administered 6