Marieke van Son

94 CHAPTER 5 Prostate cancer-related health (EORTC QLQ-PR25) was affected in the domains sexual functioning (Δ17 points) and sexual activity (Δ16 points). A clinically relevant transient increase in urinary symptoms was seen at nine months follow-up (Δ11 points), returning to baseline level afterwards. There were no statistically significant changes. Oncologic outcomes PSA nadir was reached after a median of 5.5 months (range 1-24 months). Biochemical recurrence (nadir+2) occurred in 26 patients (52%) after a median of 20 months (range 6-44 months). Using 68Ga-PSMA PET-CT for disease status assessment, 22 out of 26 patients had intraprostatic recurrence. As assessed on a subsequent 3T mp-MRI scan, 16 patients (73%) had a recurrence at the site of the treated lesion (in-field recurrence) and six patients (27%) had an out-of-field recurrence. Out-of-field recurrences were either located on the contralateral lobe (3/6) or with a distinct distance from the previous lesion site (3/6). Three out of 26 patients with biochemical recurrence had metastases without intra- prostatic recurrence on 68Ga-PSMA PET-CT. All had distant metastatic disease: one with extended nodal invasion (suspicious lymph nodes above the aortic bifurcation), one with bony metastases, and one with a suspected metastastic lesion in the right lung with mediastinal lymph node involvement. In one patient, further imaging upon biochemical recurrence was not deemed clini- cally relevant due to concurrent progressive metastatic sigmoid cancer. Two patients underwent re-salvage treatment. One received another ultrafocal sal- vage HDR-BT treatment which was well tolerated without exacerbated toxicity. The other underwent whole-gland cryoablation at a different center and was left with uri- nary incontinence requiring several pads per day. After one year follow-up, PSA-levels remain low in both patients. Six patients started ADT after a median of 15 months (range 8-32 months). Two patients died of other diseases, after 13 and 33 months respectively. After 2.5 years follow-up, BDFS was 51% (95% CI 37-69%). Metastases-free survival (MFS) was 75% (95% CI 64-89%). Hormonal treatment-free survival (HFS) was 90% (95% CI 82-99%) and overall survival (OS) was 98% (95% CI 94-100%). The Kaplan Meier survival curves are presented in Figure 3. The explorative univariable Cox regression analysis for biochemical failure revealed a small but significant hazard ratio for pre-salvage PSA (1.1, p=0.02) and size of the CTV (1.1, p=0.04), and a larger significant hazard ratio for locally advanced (stage ≥T3) tumors (2.6, p=0.02). Results are displayed in Table 2. To visualize survival differences, we stratified between “high risk of treatment failure” (stage≥T3, PSA ≥10, or PSADT ≤9 months) and “low risk of treatment failure” (stage<T3, PSA<10 and PSADT>9 months). Figure 4 shows the Kaplan Meier curves. After 2.5 years, only 25% of the “high risk” patients were free of biochemical failure, versus 71% of “low risk” patients.