SBRT With Focal Dose Escalation on DIL in Localized Prostate Cancer

Fractionated Stereotactic Ablative Body Radiotherapy (SBRT) With FOcal Dose Escalation on Dominant Lesion in Localized Prostate Cancer

Stereotactic ablative Body Radiotherapy (SBRT) is an advanced radiation technique that allows for precise delivery of higher radiation doses in fewer treatment sessions, resulting in a shorter overall treatment duration. The available clinical evidence suggests that SBRT is highly effective in controlling localized prostate cancer (PCa) with acceptable side effects.

On the other side, dose escalation is a commonly employed strategy in radiotherapy for prostate cancer. Recent studies have confirmed a dose-response relationship, demonstrating improved biochemical control with focal dose escalation to the identified dominant intraprostatic lesion (DIL) on multiparametric magnetic resonance imaging (mpMRI) of the prostate.

The hypothesis of this study is that the combination prostate SBRT with focal dose intensification on the DIL with preservation of the prostatic urethra, would lead to a higher probability of local control without a significant increase in toxicity compared to standard clinical practice.

This is a prospective single-arm phase II study designed to evaluate the effectiveness, safety and impact on quality of life of focal dose intensification using SBRT technology and extreme hypofractionated radiotherapy.

Inclusion Criteria:

• Histologically confirmed adenocarcinoma of the prostate
• Primary localized PCa, cN0 and cM0, intermediate or high-risk disease according to NCCN 2023
• Signed written informed consent for this study
• T2-T3a clinical stage with visible DIL on mpMRI
• ECOG 0-1
• Desirable prostate volume (not mandatory) < 80 cc or > 80 cc if urinary function is preserved and dosimetrically feasible
• IPSS ≤ 18 (International Prostate Symptom Score)

Exclusion Criteria:

• Unresolved previous prostatitis, symptomatic urethral stenosis
• Bilateral hip prosthesis
• T3b-4 clinical stage or N1
• M1 (presence of distant metastases)
• Previous surgery at the prostate level (Transurethral Resection of the Prostate) within the last 6 months