The Impact of Histology Subtype and Size of Giant Retroperitoneal Liposarcomas on Their Risk of Recurrence: A...

Introduction: Giant retroperitoneal liposarcomas (GRPLs) are rare tumors that often reach considerable size before diagnosis due to their indolent growth and deep anatomical location. Surgery represents the only potentially curative treatment, yet recurrence rates remain high. While histological subtype is a recognized predictor of recurrence, the prognostic role of tumor size, particularly in giant tumors, remains controversial. This study evaluates the impact of tumor size and histological subtype on recurrence risk in a literature-based retrospective cohort. Materials and Methods: Data were extracted from a literature-based database of GRLPs published between 2004 and 2023. Only tumors >20 cm treated without positive surgical margins were included; patients receiving adjuvant therapy or with missing follow-up were excluded. Histological subtype (well-differentiated vs. other) was the main variable of interest. Recurrence-free survival (RFS) was defined as the primary endpoint and estimated using the Kaplan-Meier method. The association between histological subtype and recurrence risk was evaluated using a Cox proportional hazards model. A sensitivity analysis was performed to explore the potential interaction between tumor size and histological subtype. Results: Our final cohort yielded a total of 81 patients, of whom 47 (58%) had a well-differentiated GRLPs. The median tumor size was 38 cm and median follow-up was 16 months, with 24 recurrences observed. At 24 months, RFS was higher in well-differentiated tumors than in other histological subtypes (81% vs. 41%). In multivariable Cox analysis, histology was independently associated with recurrence risk (HR 3.2, 95% CI 1.28-8.17, p = 0.01), whereas tumor size showed no association with recurrence. Interaction analysis confirmed no differential effect of tumor size across histological subtypes. Conclusions: In this literature-based cohort of GRLPs treated with surgery, histological subtype independently predicted recurrence, whereas tumor size showed no prognostic value, either overall or within individual histological subtypes.