Clinicopathological characteristics, long-term prognosis and follow-up recommendations of primary and secondary cutaneous angiosarcoma: A Danish nationwide population-based cohort study

Background: The prognostic impact of subclassifying tumors as primary and secondary cutaneous angiosarcoma (cAS) in terms of the risk of local recurrence, metastasis, disease-specific mortality, and overall survival has not been extensively investigated in previous studies. This study aimed to characterize the clinicopathological features and estimate the 2-, 5-, and 10-year rates of local recurrence, metastasis, disease-specific death, and overall survival for patients with primary and secondary cAS, and to propose a follow-up recommendation for these patients. Methods: All Danish patients diagnosed with cAS between 2000 and 2023 were included. The prognosis was estimated using age- and sex-standardized stratified cause-specific Cox-regression with all-cause mortality as a competing risk. Results: A total of 192 patients were included, comprising 99 patients with primary cAS and 93 with secondary cAS. The 5-year local recurrence rate was similar between primary (42 %) and secondary cAS (39 %). However, patients with primary cAS exhibited a higher 5-year rate of metastasis (50 %) compared to those with secondary cAS (33 %). Similarly, the 5-year disease-specific mortality was substantially higher in patients with primary cAS (57 %) compared to secondary cAS (35 %). Correspondingly, the 5-year overall survival rate was low in both primary (32 %) and secondary cAS (49 %). Conclusion: Primary cAS is associated with poorer 5-year outcomes of metastasis, disease-specific death, and overall survival compared with secondary cAS. Follow-up could be limited to 5 years, as >95 % of the relapses occurred within this period and may include clinical examinations and local MRI to detect local recurrences, and cross-sectional imaging to detect regional and distant metastases.