P138 A national retrospective cohort study reporting the epidemiology of vascular soft-tissue sarcomas in England 2013–2020

Abstract Vascular soft-tissue sarcomas (VSTSs), while rare, are a diverse group of sarcomas that carry a poor prognosis and have limited management options. The most common subtype is angiosarcoma, but this group also includes lymphangiosarcomas, malignant haemangioendotheliomas and malignant glomus tumours. Kaposi sarcoma was not included in this dataset. Epidemiological data on incidence and survival rates are scarce. National data on VSTS and cutaneous subtypes were extracted from the ‘Get Data Out’ National Disease Registration Service programme for England, 2013–20. Confidence intervals (CIs) were measured by using the exact Poisson method. Crude incidence rates (CIRs) are reported per 100 000 person-years (PY). Incidence rate ratios (IRRs) were calculated to assess the impact of the pandemic on incidence rates between 2020 and 2019 and are reported with Poisson CIs and a χ2-statistic. From 2013 to 2020, 1587 new cases of VSTS were diagnosed, with a mean of 198 cases per year and a CIR of 0.33 PY (95% CI 0.29–0.39) in 2013, which increased to 0.37 PY (95% CI 0.32–0.43) in 2020. Of these, 174 were reported as having a cutaneous origin (not including subcutaneous), with a mean of 22 per year and a CIR of 0.04 PY (95% CI 0.03–0.07) in 2013, which increased to 0.06 PY (95% CI 0.04–0.08) in 2020. The IRR for VSTS for 2020 vs. 2019 was −2.4% (95% CI 0.80–1.19; P = 0.80). The IRR for cutaneous vascular sarcoma was not significant due to small counts. The 5-year net survival reported for 2014–2016 for VSTS was 35.7% (95% CI 31.3–40.1) and was not reported for cutaneous vascular sarcomas due to small counts. Limitations of these data include the lack of more detailed data on subtype and site of VSTS, patient demographics and stage. The 2.4% reduction in incidence rates between 2020 and 2019 is nonsignificant and a smaller reduction than that seen for many other cancers during the pandemic on the background of healthcare service disruption, which may reflect the aggressive nature of VSTS. The 5-year net survival rate is similar to that of stage IV melanoma and worse than for most other skin cancers. Analysis of these data is key in highlighting this rare group of cancers, to better understand the effectiveness of current treatments and identify the direction of further research.