Geographic differences in population rates of interventional treatment for prostate cancer in Australia

Background Treatment decisions for men diagnosed with prostate cancer depend on a range of clinical and patient characteristics such as disease stage, age, general health, risk of side effects and access. Associations between treatment patterns and area-level factors such as remoteness and socioeconomic disadvantage have been observed in many countries but have not been investigated in Australia. Methods Hospital separations data for interventional treatments for prostate cancer (radical prostatectomy, low dose rate and high dose rate brachytherapy) were modelled using spatial models, generalised linear mixed models, maximised excess events tests and k -means statistical clustering. Results Geographic differences in population rates of interventional treatments were found (p<0.001). Separation rates for radical prostatectomy were lower in remote areas (12.2 per 10 000 person-years compared with 15.0-15.9 in regional and major city areas). Rates for all treatments decreased with increasing socioeconomic disadvantage (radical prostatectomy 19.1 /10 000 person-years in the most advantaged areas compared with 12.9 in the most disadvantaged areas). Three groups of similar areas were identified: those with higher rates of radical prostatectomy, those with higher rates of low dose brachytherapy, and those with low interventional treatment rates but higher rates of excess deaths. The most disadvantaged areas and remote areas tended to be in the latter group. Conclusions The geographic differences in treatment rates may partly reflect differences in patients’ physical and financial access to treatments. Treatment rates also depend on diagnosis rates and thus reflect variation in investigation rates for prostate cancer and presentation of disease. Spatial variation in interventional treatments may aid identification of areas of under-treatment or over-treatment. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement The study was funded by an Australian Research Council Linkage grant (LP200100468) and a Centre for Research Excellence grant from The National Health and Medical Research Council, Australia (1116334). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Human Research Ethics Committee of Griffith University gave ethical approval for this work (Reference: 2017/777). Data Custodians from the National Hospital Morbidity Database and the Australian Institute of Health and Welfare gave Consent for publication. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Area-level estimates of the standardised separation rate ratios are available in the Supplementary material. Area-level estimates of the standardised incidence ratios and excess hazard ratios for prostate cancer area available from the Australian Cancer Atlas (). * EHR : Excess Hazard Ratio HDR : High dose rate LDR : Low dose rate SA2 : Statistical Area 2 SIR : Standardised incidence ratio SSR : Standardised separation rate ratio