08 Brachytherapy Flashcards
Brachytherapy in PCa per NCCN 2023
EAU LDR-Brachytherapy
LDR BT uses seeds permanently implanted into the prostate. In pts declining or unsuitable for AS LDR monotherapy can be offered to those with low-risk or favourable intermediate-risk and good urinary function defined as an IPSS < 12 and maximum flow rate > 15 mL/min on urinary flow tests.
Pts having had a previous TURP can undergo BT without an increase in risk of urinary toxicity. A minimal channel TURP is recommended, leaving at least 1 cm rim of prostate tissue around the post-TURP urethral defect at the postero-lateral sides of the prostate and there should be at least a 3-month interval between TURP and BT to allow for adequate healing.
The only available RCT comparing RP and LDR BT as monotherapy was closed due to poor accrual. Outcome data are available from a number of large population cohorts with mature FU.
The biochemical DFS for ISUP grade 1 patients after 5 and 10 yrs has been reported to range from 71% to 93% and 65% to 85%, respectively. A significant correlation has been shown between the implanted dose and biochemical control. A D90 (dose covering 90% of the prostate volume) of > 140 Gy leads to a significantly higher biochemical control rate (PSA < 1.0 ng/mL) after 4 years (92 vs. 68%). There is no OS benefit in adding neoadjuvant or adjuvant ADT to LDR monotherapy.
EAU LDR-Brachytherapy combined with EBRT
LDR can be combined with EBRT in NCCN unfavourable intermediate-risk PCa and high-risk patients. External beam RT (total dose of 78 Gy) has been compared with EBRT (total dose 46 Gy) followed by LDR brachytherapy boost (prescribed dose 115 Gy) in intermediate-risk and high-risk patients in the ASCENDE-RT randomised trial with 12 months of ADT in both arms. The LDR boost resulted in 5- and 7-year PSA PFS increase (89% and 86%, respectively, compared to 84% and 75%). This improvement was achieved at a cost of increased late grade 3+ GU toxicity (18% compared to 8%). Toxicity resulted mainly in the development of urethral strictures and incontinence and great care should be taken during treatment
planning.
