Real-world data has become integral to sarcoma research

Given the rarity of sarcomas and the huge numbers of different histological and molecular subtypes, it is just not possible for classical clinical study design to achieve the critical numbers of patients required to generate new evidence that can inform management. Studies presented at the ESMO Sarcoma and Rare Cancers Congress 2025 (Lugano, 20–22 March) illustrate why real-world data (RWD) has had to evolve to fill the information gaps for clinical research.

As reported in an analysis encompassing 258 ongoing interventional sarcoma trials globally, relatively few sarcoma centres were represented in clinical trials even in high-income countries/regions, and access to any sarcoma trials in low-to-middle-income regions was very limited (Abstract 60MO). Stepping into the space is RWD, which was once treated somewhat with suspicion, but which is now enjoying increased trust not just among clinical researchers working in rare cancers, but also, crucially, among regulators according to a cross-sectional survey (Abstract 61MO). Is RWD finally shedding its ‘lower value’ label?

While researchers’ confidence in using RWD is increasing, real-world evidence (RWE) relies heavily on factors including the relevance of the study population, the expertise of the oncology team and access to the latest diagnostic and treatment modalities. Ideally, patients should be treated in reference centres, which have considerable experience in sarcomas, reflected in improved patient outcomes (Ann Oncol. 2024;35:351–363). However, a number of challenges need to be addressed. The first relates to diagnosis. A not-insignificant proportion of patients identified as having a sarcoma in the clinical setting are actually misdiagnosed (PLoS One. 2018;13:e0193330) and so central pathology review is essential to ensuring a correct diagnosis. It is also vital that centres follow, as closely as possible, international clinical practice guidelines for the tumour in question. I say ‘as closely as possible’, because not all countries/regions have the same access to recommended treatments. Indeed, collaboration is required to provide adapted guidelines that can be used in different regions globally.

Another hurdle is data inconsistency. Real-world studies build on patients’ existing health records, and the quality of these varies widely, between countries, between regions in a country and even between hospitals within a particular region. One way to address this is to mandate a standard set of data to be collected at all centres, according to guidelines. This does not need to be extensive: the key is that the data is collected consistently. The ESMO Guidance for Reporting Oncology real-World Evidence (ESMO-GROW) offers a detailed framework for reporting RWE, emphasising transparency in study design, consistent outcome definitions and comprehensive patient demographics.

A tangible step forward in realising the power of RWD will be the increased use of national or regional data collections. A comparison between national databases from France and Taiwan highlighted insightful differences in the incidence and clinical characteristics of soft tissue sarcoma in these two regions (Cancer. 2022;128:3360–3369). Information on the influence of genetic and environmental differences should help to drive tailored management approaches. Access to even more extensive databases, for example a pan-European database, would speed up the understanding and improved management of sarcomas, and this is something that countries should be encouraged to work towards.