The impact of age on clinicopathological features and treatment results in patients with localised prostate cancer receiving definitive radiotherapy

Background: This study assessed the biochemical disease-free survival (bDFS), prostate cancer-specific survival (PCSS), overall survival (OS), and side effects in patients aged < 70 and >= 70 years following definitive radiotherapy (RT). It also analysed the correlation between age at diagnosis and clinicopathological characteristics of prostate cancer (PCa). Methods: The prognostic factors for bDFS, PCSS, and OS were determined through univariable and multivariable analyses. Two age groups were also compared in terms of acute and late grade >= 2 genitourinary (GU) and gastrointestinal (GI) toxicities, the predictors of which were determined through logistic regression analysis. Results: Of the 1,328 patients, 715 (53.8%) and 613 (46.2%) were aged < 70 and >= 70 years, respectively. Median follow-up time was 84.5 months. No significant differences in the 7-year bDFS (86.3% vs. 86.8%) and PCSS rates (92.9% vs. 93.3%) were found between the >= 70 and < 70 age groups. The multivariable analysis showed that advanced clinical T stage, high International Society of Urological Pathology (ISUP) grade, and high-risk disease independently predicted poor bDFS and PCSS. Metastatic lymph nodes were another bDFS prognostic factor. The multivariable analysis identified age >= 70 years, cardiac events at diagnosis, advanced stage, higher ISUP grade, and non-use of simultaneous integrated boost technique as negative factors for OS. Additionally, diabetes and transurethral resection of the prostate (TUR-P) independently predict late-grade >= 2 GU toxicity. Interpretation: Definitive RT is a safe and effective treatment for patients with localised PCa no matter their age. Although patients over 70 years have higher risk factors and comorbidities, their bDFS, PCSS, and toxicities were comparable to those of patients aged < 70 years.