Prospective Cohort Study for Identifying Factors Predicting Long-term Outcomes of Prostate Cancer Patients Who Received Ultrahypofractionated Proton Beam Therapy
The goal of this prospective observational cohort study is to evaluate the long-term efficacy and safety of ultrahypofractionated proton beam therapy in patients with localized prostate cancer and to identify clinical and treatment-related factors associated with oncologic outcomes and treatment-related toxicity. The main questions it aims to answer are: What are the long-term biochemical recurrence-free survival, clinical progression-free survival, overall survival, and acute and late treatment-related toxicity outcomes following ultrahypofractionated proton beam therapy? Which clinical characteristics, treatment planning parameters, and patient-reported outcomes are predictive of long-term oncologic outcomes and treatment-related toxicity? Participants will: Receive protocol-based ultrahypofractionated proton beam therapy (35-40 Gy\[RBE\] in 5 fractions). Undergo routine clinical evaluation, laboratory testing including prostate-specific antigen (PSA), and imaging studies according to the institutional follow-up schedule. Complete patient-reported outcome questionnaires (EPIC-CP and Visual Analog Scale \[VAS\]) before treatment and during follow-up. Be followed prospectively to assess biochemical recurrence, clinical progression, survival outcomes, and acute and late treatment-related toxicities.
• Histologically confirmed localized adenocarcinoma of the prostate.
• No evidence of distant metastasis (M0).
• Eastern Cooperative Oncology Group (ECOG) performance status of 0-2.
• Eligible to receive definitive image-guided ultrahypofractionated pencil beam scanning proton beam therapy according to the study protocol.
• Ability to complete study questionnaires and comply with scheduled follow-up assessments.
• Provision of written informed consent before study enrollment.