1956P - Neoadjuvant chemoradiotherapy in locally advanced soft tissue sarcoma: NASAR prospective study

Background

Patients with locally advanced soft tissue sarcomas (ASTS) have a poor prognosis. Several studies attempt to analyze the role of neoadjuvant chemotherapy (NACT) and radiotherapy (NART).

Methods

Prospective unicentric study in ASTS with neoadjuvant treatment based on epirubicin (60 mg/m² day 1 and 2) and ifosfamide (1800 mg/m² d1-5), every 3 weeks for 3 cycles, concurrently with NART (46-50 Gy) starting on day 22th. Adjuvant boost of NART may be administered after surgery. ASTS greater than 5 cm, high grade and deep localization, and those initially considered as unresectable were included. Patients were evaluated by radiology before and after of neoadjuvant treatment.

Results

From 2017 until 2022, 22 patients with a median age of 43 years (range, 15-78) were enrolled in the study. 17 were men and 5 women. 13 of them were diagnosed of undifferentiated pleomorphic sarcoma, 2 angiosarcoma, 3 liposarcoma, 2 leiomyosarcoma and 2 other. 17 tumours were located in the extremities, 2 in the scapula and the other in the pelvis. The median size was 10 cm (4- 20 cm). The dose of ASTS and NART was completed in all patients. 13 patients received RT boost after surgery. The response was: 31,8% (7/22) obtained clinical response; 13,6% (3/22) partial response according to RECIST criteria; 76% (13/17) achieved a response by PERCIST criteria; and 73,3% (11/15) achieved a response by DIFUSSION criteria. The surgery was an en bloc complete resection in 95,5% patients (21/22). The histological response was ≥ than 90% of necrosis in 63,6% (14/22), with 36,4% complete response (8/22). The most frequent toxicity was delay in wound healing and 59,1% patients with skin toxicity grade 2. With median follow up of 50,1 months (range, 18-96), 10 patients remain without disease (45,5%) and 12 have had pulmonary relapses (54,5%) and only 3 local relapse (13,6%). 7 deaths were registered. Median of progression free survival is 26,1 months (95%IC 8,2 – 44,0) and median overall survival not reached.

Conclusions

Neoadjuvant treatment with ASTS concurrent with NART achieves a very high rate of pathological responses and local control. Nonetheless, systemic relapses remain. PERCIST and DIFUSSION criteria have better correlation with necrosis than the RECIST criteria.

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.