Collateral effects of the COVID-19 pandemic on endocrine treatments for breast and prostate cancer in the UK: implications for bone health

Background: The COVID-19 pandemic affected cancer screening, diagnosis and treatment pathways. This study examined the impact of the pandemic on incidence and trends of endocrine treatments in patients with breast or prostate cancer; and endocrine treatment-related side-effects. Methods: Population-based cohort study using UK primary care Clinical Practice Research Datalink (CPRD) GOLD database. There were 13,701 newly diagnosed breast cancer patients and 12,221 prostate cancer patients with ≥1-year data availability since diagnosis between January 2017-June 2022. Incidence rates (IR) and incidence rate ratios (IRR) were calculated across multiple time periods before and after lockdown to examine the impact of changing social restrictions on endocrine treatments and treatment-related outcomes, including osteopenia, osteoporosis and bisphosphonate prescriptions. Results: In patients with breast cancer, aromatase inhibitor prescriptions increased during lockdown compared to pre-pandemic (IRR: 1.22 [95% Confidence Interval: 1.11-1.34]), followed by a decrease post-first lockdown (IRR: 0.79 [95%CI: 0.69-0.89]). In patients with prostate cancer, first-generation antiandrogen prescriptions increased compared to pre-pandemic (IRR: 1.23 [95% CI: 1.08-1.4]). For breast cancer patients on aromatase inhibitors, diagnoses of osteopenia, osteoporosis and bisphosphonate prescriptions were reduced across all lockdown periods compared to pre-pandemic (IRR range: 0.31-0.62). Conclusion: During the first two years of the pandemic, newly diagnosed breast and prostate cancer patients were prescribed more endocrine treatments compared to pre-pandemic, due to restrictions on hospital procedures replacing surgeries with bridging therapies. But breast cancer patients had fewer diagnoses of osteopenia and osteoporosis, and bisphosphonate prescriptions. These patients should be followed up in the coming years for signs of bone thinning. Evidence of poorer management of treatment-related side-effects will allow us to determine whether there is a need to better allocate resources to patients at high risk for bone-related complications. ### Competing Interest Statement DPAs research group has received research grants from the European Medicines Agency; the Innovative Medicines Initiative; Amgen, Chiesi, and UCB Biopharma; and consultancy or speaker fees from Astellas, Amgen, and UCB Biopharma. DPA receives funding from the UK National Institute for Health Research (NIHR) in the form of a senior research fellowship and the Oxford NIHR Biomedical Research Centre. ### Funding Statement This research was partially funded by the European Health Data and Evidence Network (EHDEN) (grant number 806968), the Optimal treatment for patients with solid tumours in Europe through Artificial Intelligence (OPTIMA) initiative (grant number 101034347), and the Oxford NIHR Biomedical Research Centre. OPTIMA is funded through the IMI2 Joint Undertaking and is listed under grant agreement No. 101034347. IMI2 receives support from the European Union Horizon 2020 research and innovation programme and the European Federation of Pharmaceutical Industries and Associations (EFPIA). IMI supports collaborative research projects and builds networks of industrial and academic experts in order to boost pharmaceutical innovation in Europe. The views communicated within are those of OPTIMA. Neither the IMI nor the European Union, EFPIA, or any Associated Partners are responsible for any use that may be made of the information contained herein. The study funders had no role in the conceptualisation, design, data collection, analysis, interpretation of data, decision to publish, or preparation of the manuscript. ### 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 protocol for this research was approved by the Research Data Governance (RDG) Board of the Medicine and Healthcare products Regulatory Agency database research (protocol number 22_002331). 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 This study is based on data from the Clinical Practice Research Datalink (CPRD) obtained under licence from the UK Medicines and Healthcare products Regulatory Agency. The data is provided by patients and collected by the NHS as part of their care and support. The interpretation and conclusions contained in this study are those of the author/s alone. Patient- level data used in this study was obtained through an approved application to the CPRD RDG process (application number 22_002331). Data is only available directly from CPRD following RDG approval Details on how to apply for data access can be found at https://cprd.com/data-access. Analytical code and code lists for identifying the events are available in GitHub repositories: https://github.com/oxford-pharmacoepi/CancerCovidEndocrineTx