(P 318) NEOADJUVANT CHEMORADIOTHERAPY IN ADVANCED SOFT TISSUE SARCOMA. UPDATED NASAR STUDY

Objective: Patients with 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 now, 22 patients with a median age of 43 years (range, 15-78) were enrolled in the study. 17 were men and 5 women. We show results with median follow up of 36,5 months (range, 8-85).
13 of them were diagnosed of undifferentiated pleomorphic sarcoma, 2 angiosarcoma, 3 liposarcoma, 2 leiomyosarcoma and 2 other.
20 patients had histological grade 3 and 2 patients grade 2.
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 median number of cycles was 3 (range, 2-5).
The dose of RT was completed in all patients. 13 patients received RT boost after surgery.
The clinical response was only obtained in 31,8% (7/22) of the patients.
According to RECIST criteria, only 13,6% patients achieved a partial response (3/22), 72,7% a stabilization (16/22) and 13,6% a progression (3/22).
According to PERCIST criteria, 76% patients achieved a response (13/17), with complete response in 2 patients, 12% a stabilization (2/17) and only 12% a progression (2/17).
According to DIFUSSION criteria, 73,3% patients achieved a response (11/15) and 26,7% achieved no response (4/15).
The surgery was an en bloc resection, reaching complete resection in 95,5% patients (21/22).
The histological response was equal to or greater than 90% of necrosis in 63,6% (14/22), with 36,4% of the patients with a complete response (8/22) and 40,9% partial response (9/22).
The most frequent toxicity was delay in wound healing, requiring repair surgery in 2 patients, and 59,1% patients with skin toxicity grade 2.
Until now, 11 patients remain without disease (50%) and 10 have had pulmonary relapses (45,5%) and only 1 local relapse (4,5%).
7 deaths were registered (6 due to metastatic tumor progression and 1 due to another problem).
Median of progression free survival is 26,1 months (95%IC 10,9-41,3) and median overall survival not reached.

Conclusion: Neoadjuvant treatment with chemotherapy based on anthracyclines and ifosfamide concurrent with radiotherapy 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.

TABLE.docx