Radiotherapy in palliation of thoracic tumors: a phase I-II study (SHARON project).

The main clinical goal for patients with advanced or metastatic thoracic cancer is palliation of tumor-related symptoms and improvement of quality of life. The aim of this phase I-II trial was to define the maximum tolerated dose (MTD) of a short-course of palliative radiotherapy (RT) and to evaluate its efficacy in terms of palliative response. A phase I trial was planned with escalating dose increments. Total doses ranged from 16 to 20 Gy delivered (BID) in two consecutive days. Dose limiting toxicity was defined as any acute grade ≥ 3 toxicity based on the RTOG scale. MTD was used in the phase II trial to evaluate the efficacy of this regimen using a two stage Simon's design. Fifty-four patients were enrolled. The upper dose level of 20 Gy was defined as the MTD. In patients treated with this dose, the overall palliative response rate was 96.5% (CI 0.95: 81.3-99.9%). Complete pain relief rate was 50.0%. Median survival without symptomatic progression was 3 months. The tested short course accelerated regimen was well tolerated and effective in the palliative setting of metastatic or locally advanced chest cancer. A phase III trial is ongoing to validate this RT schedule.Trial registration: NCT03465553.