Long-term Outcomes of Salvage Radiotherapy Using TomoTherapy With Image-guided Radiotherapy for Postoperative Prostate Cancer Patients.

Abstract

Background/aim: This study aimed to evaluate the long-term outcomes, treatment-related toxicity, and factors affecting postoperative prostate cancer patients treated with intensity-modulated radiation therapy and image-guided radiation therapy (IMRT-IGRT) using TomoTherapy as salvage radiotherapy (SRT).

Patients and methods: A total of 71 consecutive patients who underwent SRT after radical prostatectomy between 2011 and 2023 were included in the study. Treatment outcomes, including the progression-free rate (PFR) and overall survival, were calculated using Kaplan-Meier curves. Associations between treatment outcomes and factors were analyzed using the Cox proportional hazards regression analysis.

Results: The median follow-up time after SRT was 60 months (range=1-148 months). The 5-year and 10-year PFR were 69.05% and 54.73%, respectively. In multivariate analysis, maximum PSA >0.7 ng/ml was significantly associated with worse PFR (p<0.05). Additionally, eight patients (11.3%) experienced late grade 2 genitourinary toxicity, and one (1.4%) patient developed late grade 2 gastrointestinal toxicity. No adverse events were rated higher than grade 3.

Conclusion: Our findings demonstrate a comparable PFR at 5-year (69.05%) and 10-year (54.73%) intervals with those of previous reports, confirming the efficacy of IMRT-IGRT as a viable option for SRT. Worse PFR was associated with factors such as mass PSA >0.7 ng/ml, providing critical insights into prognostication. SRT for prostate cancer with IMRT and IGRT using TomoTherapy showed similar treatment outcomes and low toxicity rates compared with those of previous studies.