Abstract 127P
Background
There is an unmet need of new effective therapies for patients (pts) with DDLPS. To date, the most important prognostic factor is the anatomical location. A few studies found myogenic differentiation correlated with worse survival in retroperitoneal DDLPS. However, specific prognostic molecular markers have not yet been identified.
Methods
We reviewed data of pts with DDLPS treated between 2018 and 2023 at Veneto Institute of Oncology. The impact of age, gender, tumor location, grading, differentiation, size, surgery and chemo/radiation-therapy on disease-free survival (DFS) and overall survival (OS) was analyzed for pts who underwent surgery. The effects on progression-free survival and OS of the tumor location, grading and differentiation were studied for pts treated with first-line chemotherapy. The primary objective was the identification of clinical and morphological biomarkers, that may then guide research of the underlying molecular mechanisms.
Results
A total of 61 pts were eligible (Table). Of these, 58 pts underwent surgery. Median follow-up was 28 months (range 22-46 months). In pts who underwent surgery, a high tumor grade was associated with worse survival (p=0.001). Also, poorer prognosis was observed when a rhabdomyosarcomatous component was present, with a median DFS of 3 months (median DFS: NA, 3, 25 and 62 months for myogenic, rhabdomyoblastic, NOS and other types of differentiation, respectively; p=0.002), even after adjusting for the anatomical location (OR 23.95, 95% CI 3.26-175.7; p=0.002). Table: 127P
Patient characteristics
| VARIABLES | TOTAL: 61 (100%) |
| Median age at diagnosis (months) | 67.8 (43-88) |
| Anatomical Location Retroperitoneum Extremities Other sites | 36 (59) 15 (24.6) 10 (16.4) |
| Histologic Differentiation Myogenic Rhabdomyoblastic Other types of differentiation NOS | 11 (18) 2 (3.3) 12 (19.7) 36 (59) |
| Tumor Grade G3 G2 NOS | 27 (44.3) 32 (52.4) 2 (3.3) |
Conclusions
Our study confirms certain morphological features, such us the type of differentiation, may have a prognostic value. Next steps include the identification of molecular biomarkers, in order to improve prognostic stratification and therapeutic planning for pts with DDLPS.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.