Marieke van Son

54 CHAPTER 3 Iodine-125 brachytherapy (n=17) reported no grade >1 toxicity, no significant deterio- ration in IIEF and a similar transient IPSS increase(18). A comparison with other FT modalities confirms the common theme with a minimum impact on QoL and genitourinary functions(4). A single-centre study evaluated pro- spective data on multiple FT modalities including cryotherapy (n=50, hemi-ablation), HIFU (n=21, hemi-ablation), photodynamic therapy (n=23, focal) and brachytherapy (n=12, focal)(19). Between baseline and 12 months follow-up, IPSS remained stable (<5 points median difference). However, IIEF deteriorated in all groups (median 5-10 points change). Alternatively, comparing our results to whole-gland HDR-brachytherapy series which are usually performed in multiple fraction schedules(20), we find that late grade 3 GU and GI toxicity were observed in 0-16% and 0-2% of patients, respectively. Late grade 2 GU and GI toxicity were seen in 0-40% and 0-13%. These results are inferior to our toxicity numbers: no grade 3 GU toxicity, only 13% grade 2 GU toxicity (4/30), and no grade >1 GI events. Morton et al. compared single-dose 19Gy (n=87) with 2x13.5Gy (n=83) in a ran- domised controlled trial of low/intermediate-risk patients with a median follow-up of 20 months(21). Grade 2 GU toxicity was frequent in both treatment arms (51% acute and 31% late) and grade 3 GU toxicity occurred in 2 patients. Grade 2 acute and late GI toxicity was limited to 2% (single-dose) and 3% (two fractions). Grade 2 ED occurred in 12% and in 29%. As measured by the Expanded Prostate Cancer Index Compos- ite (EPIC), patient-reported ED occurred in 34% and in 58%. Although CTCAE-graded ED scores are favourable compared to our results (40% newly developed grade 3 ED), patient-reported erectile function seems comparable. A potential explanation for the favourable ED results of Morton et al. could be their lower patient age: 65 versus 71 years in our patient group. A study by Prada et al. (n=60, low/intermediate-risk patients, 1x19Gy, median fol- low-up 72 months) reported even lower toxicity: no new grade 2 GU or GI toxicity oc- curred. Rectal spacers were used to limit rectal dose. Potency was not reported(22). Their subsequent study (n=60, low/intermediate-risk patients, 1x20.5Gy, median fol- low-up 51 months) similarly showed no grade 2 GU or GI toxicity(23). A critical note to these results is the lack of data on patient-reported QoL, which may have yielded a different outcome. Our 4-year BDFS of 70% is clearly lower than the 79-100% BDFS at 3-10 years in frac- tionated whole-gland HDR-brachytherapy series(20). Lower BDFS was also reported by Prada et al. after 1x19Gy whole-gland HDR-brachytherapy: 66% for low-risk and 63% for intermediate-risk patients after 6 years(22). In contrast, BDFS after 1x20.5Gy whole-gland HDR-brachytherapy was much higher (82% at 6 years), even though a higher proportion of intermediate-risk patients were treated (57% in the 20.5Gy study vs. 27% in the 19Gy study)(23). Although the α/β ratio of prostate cancer is thought to be low (approximately 1.5)(24), which is an argument for hypofractionation, single-dose 19Gy might be a suboptimal therapeutic dose.