The goal of this clinical study is to evaluate the toxicity and efficacy of re-irradiation using focal stereotactic body radiotherapy (SBRT) in patients with local recurrence of prostate cancer after definitive or post-operative radiotherapy.
The main question is the tolerance of such treatment, concerning the incidence of Grade ≥ 2 and Grade ≥ 3 GU and GI toxicity. Also the efficacy of SBRT will be measured in terms of Biochemical Control with other secondary endpoints which include: Biochemical Response, Biochemical Failure-Free Survival, Metastases-Free Survival, Relapse-Free Survial, Local Control, Overall Survival and patients' reported tolerance measured with Quality of Life questionnaires (QoL C-30 and PR-25).
The evaluation of the tolerance and effectiveness of stereotactic radiotherapy (SBRT) will be performed in 3 subgroups: in patients with local recurrence after conventionally fractionated/moderately hypofractionated definitive radiotherapy (Group A) or ultrahypofractionated definitive SBRT (Group C) or after prostatectomy and post-operative radiotherapy (Group B).
The study group is planned to include 55 patients.
Local recurrence of prostate cancer after definitive radiotherapy
biopsy proven or/and
Consistent MRI and PET-PSMA results and PSA growth dynamics
Time since primary radiotherapy - at least 2 years
Polymetastatic dissemination in distant or regional lymph nodes (N1, M1) or oligometastatic dissemination, but not eligible for local forms of metastasis directed therapy (MDT)
Tumour volume (GTV) > 14 cc
Poor tolerability of primary radiotherapy (≥G3 toxicity) or persistent late toxicity ≥G2 interfering with re-irradiation
Severe dysuria before repeated SBRT (e.g., IPSS ≥19)
Single group
Stereotactic Body Radiotherapy
RadiationSalvage SBRT will be performed in three subgroups of patients with local recurrence: Group A - after conventionally fractionated/moderately hypofractionated definitive radiotherapy; Group B - after prostatectomy and postoperative radiotherapy; Group C - after ultrahypofractionated definitive SBRT Target volumes: GTV- tumour visible on MRI and PET-CT; CTV- 1-3 mm margin around GTV PTV- 3 mm around CTV\* \*- in cases in which very high accuracy and reproducibility of SBRT are ensured, and the margin overlaps the rectum and/or bladder, it is possible to reduce the margin from these organs to 1 mm. Dose constrains: The criteria for limiting the dose in nearby organs are not well-defined for repeated irradiation - the following doses should be aimed: * Maximum rectal dose ≤103% of the prescribed dose (optimal ≤100%) * Maximum bladder dose ≤105% of the prescribed dose (optimal ≤103%) Dose-volume constrains: Rectum: • D30% \<15Gy Bladder: • D30% \< 15 Gy
Tolerance of salvage SBRT
Assessment of early and late radiation toxicity: Grade ≥ 3 radiation-induced bladder/urethral (GU) and bowel/rectal (GI) adverse events toxicity or other, according to CTCAE criteria
Tolerance of salvage SBRT
Rate of moderate or worse early and late radiation toxicity: Grade ≥ 2 radiation-induced bladder/urethral (GU) and bowel/rectal (GI) adverse events toxicity or other, according to CTCAE criteria
Biochemical Control
Biochemical Control will be defined as observations without biochemical recurrence defined as PSA concentration: a. \>2 ng/mL above the nadir (according to Phoenix) for groups A and C b. \>0.2 ng/ml (according to AUA) for group B
Biochemical Response
Decrease in PSA level below baseline (pre-SBRT)
Biochemical Failure-Free Survival (BFS)
Biochemical Failure Free Survival (BFS) is defined as the time interval between SBRT and biochemical, local, regional failure, distant metastasis or death irrespective of the cause
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