Prostate radiotherapy biomarker review found timing more limiting than assay choice

KEY POINTS

• The scoping review screened 3,499 records from PubMed, Scopus, and Web of Science and included 45 human studies evaluating blood-accessible biomarkers within prostate radiotherapy pathways.
• Four prespecified domains were examined: γ-H2AX and DNA-damage response, IL-6 and inflammatory mediators, galectin-1/3 immune–stromal biology, and testosterone or endocrine recovery.
• Testosterone had the largest evidence base with 28 studies, followed by inflammatory mediators with 12 and γ-H2AX with five. No eligible study evaluated repeated circulating galectin-1 or galectin-3 kinetics anchored to prostate radiotherapy.
• γ-H2AX studies generally sampled blood within minutes to hours of a radiotherapy fraction, sometimes extending to 24 hours. Interpretation was limited by inconsistent blood processing, cell selection, fixation, scoring, and reporting of exact post-fraction intervals.
• IL-6 and related inflammatory studies mainly sampled during radiotherapy or soon afterward and linked changes to acute toxicity, fatigue, symptoms, or inflammatory phenotypes. None directly validated serial inflammatory trajectories against biochemical control, metastasis-free survival, or overall survival.
• Testosterone studies provided the most developed longitudinal literature, but radiotherapy-only kinetics and recovery after radiotherapy plus androgen deprivation represent different biological questions. Baseline sampling relative to androgen-deprivation initiation and cessation was often poorly defined.
• A dedicated sensitivity search found 36 galectin records, assessed seven full texts, and identified no additional eligible study. The review performed no formal risk-of-bias assessment or meta-analysis, and its proposed timing windows are study-design considerations rather than validated clinical schedules.

CLINICAL TAKEAWAY

SOURCE

Cancers