ESTRO 2022 - Abstract Book

S1215

Abstract book

ESTRO 2022

Results The median age of 55 years (range 19-86). In term of histology, 26,6% were GII and 73,3% GIII. Patients were treated in 3D/IMRT 8/37. GTV: defined MRI; CTV: GTV +2,5cm. Patients received 50 Gy in 25 fractions at 5/week, with 3 cycles of Epirubicin 60mg/m2/d d1-2 + Ifosfamide 3g/m2/d d1-3 each 3 weeks. 66,6% patients had no acute Radiodermitis G>3. No dose-reductions or interruptions (>2 days) were registered. All patients completed RT, and 32 were evaluated for response. By RECIST: 11 achieved PR (34,3%), 15 SD (46,8%), 6 PD (18,7%). By Choi: 19 achieved PR (59,3%), 10 SD (31,2%), 3 PD (9,3%). Median time from the end radiotherapy to surgery was 33 days (range, 11-74 days). Median pathological response was 87% (range 15-100%). With a median follow-up of 30 months (4 - 51 months), there were 10 progression and 4 death events Conclusion RT-CT preoperative have shown relevant clinical activity in ASTS, favorable safety profile and antitumor activity in the preoperative setting of patients affected by ASTS J. VELASCO JIMÉNEZ 1 , J. Velasco Jiménez 2 , M. López Valcárcel 3 , P. Sánchez Rubio 4 , M. Hernández Miguel 3 , A. Valcárcel Diaz 3 , L. Paisan Palacio 3 , S. Santana Jimenez 3 , B. Gil Haro 3 , O. Engel 3 , C.A. Regueiro Otero 5 , J. Romero Fernández 5 1 PUERTA DE HIERRO MAJADAHONDA HOSPITAL, RADIATION ONCOLOGY, MAJADAHONDA, Spain; 2 CEU San Pablo, Medicina, MADRID, Spain; 3 Puerta de Hierro Majadahonda Hospital, Radiation Oncology, Majadahonda, Spain; 4 Puerta de Hierro Majadahonda Hospital, Physics, Majadahonda, Spain; 5 Puerta de Hierro Majadahonda Hospital , Radiation Oncology, Majadahonda, Spain Purpose or Objective In-transit metastases (ITM) of melanoma are locoregional recurrences confined to superficial lymphatics. Occurrence is 3.4– 6.2%. Disproportionately in lower limbs due to gravity and greater lymphatic network. We present a retrospective review of an innovative technique. Materials and Methods Five consecutive patients treated between April 2011-august 2018 with tomotherapy using hypofractionated regimen of 30 Gy in 6 fractions at 2 fractions/week over 3 weeks. First patient received 3 x 8 Gy and last patient an integrated boost (SIB) to the macroscopic lesions 5 x 7 Gy with concomitant Nivolumab. The last patient received concomitant Ipilimumab. PTV30 was defined as all GTV including the primary and superficial lymphatics up to the proximal lesion leaving a corridor with at least a band free from the circumference (first patient PTV had donut shape thus corridor was inside PTV). RECIST was used to assess primary outcomes. Adverse Events assessed using CTCAE V5.0 Results Patients and responses shown Table 1. Mean follow-up was 31.9 (2.1-40) months. Mean CTV/ PTV volume were 658cc (106- 1389) and 1270 cc (241-1693). PTV mean V30, V28,5 and V27 were 54.7%, 89.5% and 98,3%. Mean corridor volume was 1566cc (243-5008). Corridor mean dose V20, V15 and V10 were 15.6%, 18% and 40%. AEs are shown in Table 2. Of note is acute edema in the first patient and skin toxicity in the patient who received an integrated boost with nivolumab both resolved. PO-1434 Innovative radiotherapy technique for the treatment of in-transit or metastatic lower limb melanoma