Retrospective Cervical Cancer Oligo States (Recurrence, Metastasis) Multicentre Outcomes Study.

This is a multicentric, retrospective registry designed to evaluate clinical outcomes in patients with (induced) oligo-metastatic and oligo-recurrent cervical cancer. These patients will be identified using an adapted ESTRO-ASTRO consensus definition. The study aims to investigate the role of radiation therapy-whether high-dose, stereotactic ablative, or re-irradiation-in combination with or without systemic chemotherapy, immunotherapy, or targeted agents, in improving survival outcomes and minimizing treatment-related toxicity. Despite systemic chemotherapy being the current standard for metastatic cervical cancer, the survival benefits remain modest. Emerging evidence, including findings from the SABR-COMET trial and institutional experiences, suggests that selected patients with limited metastatic burden may derive survival benefit from integration of local therapies. However, for cervical cancer specifically, there is limited consensus on the optimal use of radiation in the oligometastatic or oligorecurrent setting.

This registry seeks to capture real-world data from EMBRACE-participating centers to explore treatment patterns, dose-response relationships, and toxicity profiles. The primary objective is to determine overall survival, with secondary endpoints including in-field and overall progression-free survival, treatment-related toxicity, and development of prognostic risk groups. The registry will also support development of a nomogram and a framework for future translational research, including tissue collection. Data will be collected through a centralized, secure electronic data capture system (Castor EDC) hosted at Erasmus University Medical Center. Each participating site will enter anonymized patient data into standardized case report forms derived from patient records. Built-in data validation rules and consistency checks will be used to ensure data quality, with each center responsible for accuracy and source verification. A central data dictionary standardizes variable definitions and coding. The data will be managed under established standard operating procedures covering data collection, quality control, and analysis. Statistical analysis will include descriptive summaries, Kaplan-Meier survival curves, Cox regression modeling, and dose-response assessments. Approximately 350-400 patients treated between 2007 and 2021 are expected to be included. The registry does not involve direct patient contact and poses minimal risk, with all ethical approvals and data protection safeguards in place, including local IRB clearance and waiver of consent where applicable. This registry aims to inform future clinical trials and guidelines for personalized treatment in oligo-metastatic and oligo-recurrent cervical cancer.