Eenmalige plaatselijke inwendige bestraling voor de behandeling van patiënten met teruggekeerde prostaatkanker

Despite improvements in primary curative treatment modalities, prostate cancer recurrences are common. Various salvage treatments, such as radical prostatectomy, low-dose-rate brachytherapy, external beam radiotherapy, high intensity focused ultrasound and cryosurgery have been investigated. However, because of high failure and toxicity rates, these treatment modalities remain unpopular. High failure rates can be reduced by excluding patients with high risk characteristics for early distant metastases, for whom local salvage treatment has no benefit. High toxicity rates in whole-gland salvage irradiation therapies are caused by accumulation of dose to surrounding organs at risk. To reduce toxicity, focal therapy is warranted. With advancements in imaging modalities, determination of the exact tumor location has become possible, in addition to adequate exclusion of metastatic disease. Currently, the radiotherapy department in the University Medical Centre Utrecht has a 1.5T magnetic resonance imaging (MRI) high-dose-rate brachytherapy (HDR-BT) facility, allowing for optimal visualization during treatment. With this facility, focal treatment is possible by inserting catheters into the tumor under MRI-guidance. Due to the steep dose fall-off in brachytherapy, low radiation doses will be expected in the surrounding healthy tissues, while maximum dose can be applied to the tumor. Therefore, less toxicity to the organs at risk is expected, while tumor control is maintained. In earlier studies, it was shown that salvage HDR-BT is feasible. Moreover, results regarding toxicity are promising. Therefore, we expect that focal salvage MRI-guided HDR-BT will be of benefit in patients with locally recurrent prostate cancer.

The purpose of this study is to evaluate toxicity and oncologic outcomes of MRI-guided focal salvage high-dose-rate brachytherapy (HDR-BT). In earlier studies, it was shown that focal salvage HDR-BT is feasible and results regarding toxicity are promising. Therefore, it is expected that focal salvage HDR-BT will be of benefit in patients with locally recurrent prostate cancer, with respect to both toxicity and tumor control.

The treatment includes one high-dose-rate brachytherapy procedure, administering 19 Gy in a single session.
Questionnaires will be used to assess toxicity and quality of life (before treatment, one month after treatment, every 3 months the first year, every 6 months the second year, thereafter once a year for up to 10 years). For assessment of biochemical recurrence, PSA monitoring will be performed during each visit.

Follow-up time points:
4 weeks, 3 months, 6 months, 9 months, 12 months, 18 months, 24 months, 36 months, 48 months, 60 months, 72 months, 84 months, 96 months, 108 months, 120 months.

Single fraction focal high-dose-rate brachytherapy to a dose of 19 Gray