Surgery or radiotherapy for early-stage cancer study protocol for an emulated target trial of radical radiotherapy versus radical cystectomy, with either following neoadjuvant chemotherapy, for organ-confined muscle-invasive bladder cancer.

introductionNeoadjuvant chemotherapy (NAC) followed by definitive treatment consisting of either radical radiotherapy or radical cystectomy is the recommended treatment for patients with organ-confined muscle-invasive bladder cancer (OC-MIBC). A randomised controlled trial (RCT) aimed to compare the effectiveness of radical radiotherapy and radical cystectomy but failed to recruit. Radical radiotherapy is non-invasive and organ-preserving, and observational studies have suggested this treatment may be associated with similar outcomes compared with radical cystectomy. However, in these observational studies, the risk of confounding was high, and they did not consider the receipt of NAC. The surgery or radiotherapy (SORT) for the early-stage cancer study will assess the comparative effectiveness and cost-effectiveness of either radical cystectomy or radical radiotherapy, both after NAC for OC-MIBC. We will use a target trial emulation approach to reduce the risk of bias when assessing comparative effectiveness from observational data. METHODS AND ANALYSIS: The SORT study will use UK's National Cancer Registry to identify individuals diagnosed with urothelial OC-MIBC (T2-4aN0M0) between 1 January 2015 and 31 December 2021 who received either radical radiotherapy or radical cystectomy after NAC. The data will be linked to Hospital Episode Statistics (HES), National Radiotherapy Data Set (RTDS) and Systemic Anti-Cancer Therapy (SACT) data sets to gather information on clinical, tumour and socio-demographic characteristics and receipt of treatment. Using the target trial emulation framework, we will define the eligibility criteria and radical radiotherapy and radical cystectomy receipt. To reduce the risk of confounding, we will use advanced statistical approaches to allow for differences in measured baseline characteristics between the comparison groups.The primary outcome is 3-year all-cause mortality after radical treatment receipt. Secondary outcomes will include all-cause and bladder-cancer-associated mortality at 3 and 5 years, time to death, incremental costs and incremental cost-effectiveness reported according to net health benefits. ETHICS AND DISSEMINATION: The study was approved by the London School of Hygiene and Tropical Medicine Ethics Committee (Reference number 29717 - 1). Results will be communicated in open-access journals and conferences to clinicians, researchers, patients and policymakers.