To report the outcome of hypo-fractionated radiotherapy after radical prostatectomy (RP) for prostate cancer (PCa) using IMRT-SIB. 124 patients with PCa at high risk of relapse after RP or diagnosis of biochemical relapse were included. Patients received 62.5 Gy to the prostate bed (PB) and 45 Gy to pelvis nodes in 25 fractions. Androgen suppressive therapy was prescribed based on NCCN risk categories. Median follow-up was 30 months.

To report the outcome of hypo-fractionated radiation therapy after radical prostatectomy (RP) for prostate cancer (PCa) using intensity-modulated radiation treatment with simultaneous integrated boost (IMRT-SIB).

One hundred and twenty-four patients with PCa at high risk of relapse after RP or diagnosis of biochemical relapse were included in this phase II study (adjuvant: 106 patients, salvage: 18 patients). All patients received 62.5 Gy to the prostate bed (PB) and 45 Gy to pelvis nodes in 25 fractions. Androgen suppressive therapy was prescribed based on NCCN risk categories. Acute and late toxicities were recorded and evaluated according to RTOG (Radiation Therapy Oncology Group) criteria and RTOG-EORTC (European Organization for Research and Treatment of Cancer) scale, respectively.

Median follow-up was 30 months (13-92).

Inclusion Criteria:

• > 18 years
• prior radical prostatectomy with or without lymphadenectomy
• high-risk patients (positive surgical margins, and/or extracapsular extension, and/or seminal vescicle invasion, and/or probability of nodal metastasis > 7% calculated by the Roach formula after pelvic lymph node dissection with ≤ 13 nodes removed, and/or presence of any positive pelvic nodes) or patients with biochemical relapse (initial post-surgery serum PSA equal or above 0.2 ng/mL with a second confirmatory PSA of the same value)
• ECOG performance status 0-1
• adequate bone marrow function (hemoglobin concentration > 8 g/dl, white blood cell count > 3,000/ mm³, platelet count > 75,000/ mm³)
• pre-treatment computed tomography (CT) scan or magnetic resonance imaging (MRI) of the abdomen and pelvis
• bone scan
• informed consent

Exclusion Criteria:

• prior pelvic radiotherapy
• distant metastases
• macroscopic residual tumor
• pelvic or para-aortic nodes at re-evaluation imaging after surgery
• secondary malignancies
• genetic syndromes of hyper-radio-sensitivity
• chronic inflammatory bowel disease
• previously treated with androgen deprivation therapy
• previously treated with chemotherapy for prostate cancer