# Meta-core outcome set for randomized trials and clinical practice for curative surgical oncology: patient and healthcare consensus statement

## TL;DR

This paper describes the creation of a standardized set of outcomes for surgical cancer trials and clinical practice, developed through consensus among stakeholders.

## Contribution

The novel contribution is a meta-core outcome set applicable across all cancer types in surgical oncology, developed through stakeholder consensus.

## Key findings

- Eight core outcomes were agreed upon, including overall survival and quality of life.
- The meta-COS aims to standardize outcomes reporting in surgical oncology trials and practice.
- The process involved a Delphi survey and consensus meeting with diverse stakeholders.

## Abstract

The development and use of core outcome sets (COSs) have the potential to inform best practice in healthcare treatment options by facilitating data synthesis across studies. In surgical oncology, eight cancer-specific COSs exist, and these overlap in content. The development of a meta-COS that includes the core outcomes from existing cancer data sets would be applicable, as a minimum, across all cancer types in surgical oncology for use in effectiveness trials and clinical practice.

The process of developing a meta-COS included identification of the existing COS and their discussion with 3 different stakeholder focus groups (surgeons/oncologists, other healthcare professionals, and patients and carers). Outcomes were identified through a review of the literature and registered clinical trials. Stakeholders representing healthcare professionals (surgeons/oncologists and others) were recruited from national societies, regional cancer networks, and local trial centres, whereas patients and carers were recruited using independent representative organizations. The aim was to include at least two individuals from each group for the ten common cancers requiring surgery. These ten cancer types were regarded as the commonest based on global incidence in World Cancer Research Fund data. An agreed-upon list of outcomes was scored in a two-round online Delphi survey (March–May 2025). The results of this survey were discussed and ratified at an online consensus meeting (June 2025) by Delphi participants who completed both rounds, members of the stakeholder groups, and patients. The 80% threshold defined consensus.

Forty-five participants completed both survey rounds, and 15 participated in the consensus meeting. Of 317 outcomes initially identified, 35 were discussed with stakeholders, 32 were scored in Delphi rounds, and consensus was achieved on eight core outcomes to include in the surgical oncology meta-COS: overall survival, disease-free survival, disease-specific survival, death related to surgery, delay to further treatment, completeness of tumour removal, overall quality of life, and serious adverse events.

This meta-COS for surgical oncology offers a standard set of outcomes to be used in surgical oncology studies and clinical practice, regardless of cancer type.

This article describes the consensus-driven development process of a minimum set of outcomes that should be reported in cancer surgery trials across specialities. This does not detract from previous work within those specialities, but supplements them and, more importantly, assists in cancer trials where the cancer types are still without a core outcome set for reference.