ESTRO 2024 - Abstract Book

S1895

Clinical - Mixed sites, palliation

ESTRO 2024

consecutively observed at our Radiotherapy Unit matching the inclusion criteria were enrolled. Each enrolled subject was included in a different phase I study arm, according to the lesion site (lung, liver, bone, metastatic), and sequentially assigned to a particular dose level, as detailed in Table 1. Toxicity profile, lesion response at 4 months, and early local control (LC) were investigated and reported.

Results:

227 lesions in 164 consecutive patients (male/female: 97/67, median age: 68 years; range: 29-92) were treated. The main primary tumours were: breast cancer (39 patients), colon cancer (47 patients), and prostate cancer (60 patients). More details are shown in Table 2. The prescribed dose ranged from 12 (BED(2Gy, α/β:10) = 26.4 Gy) to 28 Gy (BED(2Gy,α/β:10) = 106.4 Gy) to the planning target volume. Twenty -seven patients (16.4%) experienced grade 1 2 and only one grade 3 acute toxicity, which was a pulmonary one. In terms of late toxicity, we registered only 5 toxicity>G2: a G3 gastro-intestinal one, three G4 bone toxicity, and a G3 laryngeal toxicity. For tumour response, only 199 lesions were evaluable: 107 (53.8%) complete responses, 50 (25.1%) partial responses, 31(15.6%) stable responses, and 11 (5.5%) progressions, obtaining an ORR of 94.5%. Regarding LC, the overall 1-,2-, and 5-years LC were 90.7%, 81.7%, and 69.5% respectively.