Optimising Radiotherapy for Prostate Cancer: Comparison of Treatment Schedules and Toxicities

Background Prostate cancer is one of the most common malignancies diagnosed among men worldwide, ranking second in terms of incidence, and is managed using a multimodality treatment approach. Radiotherapy remains a cornerstone in the management of localized and locally advanced disease. Although conventional fractionated radiotherapy (C-RT) has historically been the standard of care, accumulating radiobiological evidence supports the use of hypofractionated regimens. Prostate cancer exhibits a low α/β ratio (typically 1.5-3 Gy), indicating greater tumor sensitivity to larger fraction sizes and providing a strong radiobiological rationale for hypofractionated radiotherapy (hypo-RT) without escalating late toxicity to surrounding normal tissues. Aim This study aimed to compare biochemical recurrence-free survival (bRFS) and toxicity profiles between moderate hypo-RT and C-RT. Materials In our study, we analysed the data of 20 patients treated between January 2022 and January 2024. Patients received either moderate hypo-RT (70 Gy in 28 fractions) with an EQD2 of 77 Gy or C-RT (80 Gy in 40 fractions). Treatment planning involved daily cone beam CT (CBCT)-based image guidance and strict bladder-rectal protocols. Target delineation adhered to the European Society for Radiotherapy and Oncology (ESTRO)-European Organisation for Research and Treatment of Cancer (EORTC) contouring guidelines. Toxicities were assessed using the Radiation Therapy Oncology Group (RTOG) criteria and quality of life (QoL) by the International Prostate Symptom Score (IPSS). Results At a median follow-up of 24 months, bRFS was comparable between the two treatment groups. Grade ≥2 gastrointestinal (GI) and genitourinary (GU) toxicities did not differ significantly between hypo-RT and C-RT arms (p>0.05). Urinary symptom-related outcomes were similar across groups, with no statistically or clinically meaningful differences observed. Conclusion Moderate hypo-RT takes advantage of the radiobiological properties of prostate cancer with its low α/β ratio in achieving comparable oncologic outcomes with minimal early and late toxicities in intermediate-risk and high-risk prostate cancer without affecting the QoL.