Variation in radiotherapy patterns of care in the radical treatment of South Australian men with non-metastatic prostate cancer between 2005–2015

Background and purpose: To investigate associations between socio-demographic characteristics and radiotherapy patterns of care in non-metastatic prostate cancer [nmPCa] in South Australia [SA] between 2005–2015 and document practice patterns over time. Materials and methods: Men with nmPCa receiving primary curative radiotherapy were identified from SA Prostate Cancer Clinical Outcomes Collaborative database. Adjuvant, salvage and palliative therapies were excluded. Associations between socio-demographic factors (age, residence, socio-economic status, diagnostic period) and radiotherapy mode (external beam radiotherapy [EBRT] vs. brachytherapy [BT]) and technique (low-dose-rate vs. high-dose-rate brachytherapy) were investigated using multivariable logistic regression with separate models for clinical risk categories. Results: Of the 1874 men who underwent primary RT, 80% received EBRT and 20% BT. For low and intermediate risk disease, likelihood of receiving EBRT was higher among older men (OR_low = 3.08; 95% CI 1.82–5.22 and OR_intermediate = 3.48; 2.28–5.31 for 65–74 yrs vs. <65 yrs) and lower among regional/remote compared with metropolitan residents (OR_low = 0.34; 0.17–0.67 and OR_intermediate = 0.57; 0.34–0.94). For intermediate and high risk disease, more recent diagnosis was associated with decreased likelihood of EBRT (OR_intermediate = 0.22; 95% CI 0.15–0.33 and OR_high = 0.50; 0.29–0.88, respectively). Among men receiving BT, low-dose-rate BT use decreased over time for low (OR = 0.19; 0.04–0.89) and intermediate risk disease (OR = 0.32; 0.12–0.84). Dose escalation and intensity modulation for EBRT increased after 2010. Conclusion: Over the last decade substantial changes in RT for nmPCa were observed. Older age and more remote residence may be barriers to accessing specific types of RT. Further research to understand how these factors affect access is warranted to improve service provision.