Liposarcoma subtype recurrence and survival: A UK regional cohort study.

BACKGROUND:Clinical outcome data in the United Kingdom, Europe, and the United States have yet to facilitate appropriately specific surveillance for liposarcoma histological subtypes, despite being one of the most common soft tissue sarcomas. Therefore, this study aims to demonstrate histologic-specific differences in liposarcoma recurrence, disease progression, and survival and discuss the implications. METHODS AND FINDINGS:This cohort study involves patients from a regional sarcoma service in the UK who have had a primary surgical excision of liposarcoma between October 2002 and September 2019. The median follow-up is five years. Confirmed histopathological diagnoses of liposarcoma (n = 193) are organised according to the World Health Organisation recognised subtypes: atypical lipomatous tumours (ALT), myxoid, pleomorphic, and dedifferentiated liposarcomas. In addition, retroperitoneal variants (n = 34) are included to illustrate the broader spectrum of phenotypes. The primary outcomes were local recurrence, distant disease progression, and disease-specific death, and compared using Kaplan-Meier analyses and tumour variables using Cox proportional hazard analyses. All three primary outcomes significantly differed (P < 0.0001, n = 193). There were no metastases or disease-specific death in patients with ALT (n = 92) and no metastases of their retroperitoneal counterparts (n = 17). Amongst the metastasising cases of rarer subtypes, there were pulmonary spread of pleomorphic (8/9, n = 20), dedifferentiated (4/5, n = 18), and myxoid (2/3, n = 29) liposarcomas. CONCLUSION:An absence of metastases of ALT should be considered alongside global evidence. Surveillance protocols could better differentiate between these subtypes and, in doing so, save patients a considerable amount of irradiation, time, fear, and anxiety.