Managing Pulmonary Oligometastatic Disease with Stereotactic Body Radiation Therapy—Moving the Field Forward 1 Organ at a Time
Mené en Australie et en Nouvelle-Zélande entre 2015 et 2018 sur 90 patients présentant des oligométastases pulmonaires, cet essai randomisé multicentrique de phase II évalue l'efficacité et la toxicité d'une radiothérapie stéréotaxique d'ablation en fonction du type de fractionnement des rayonnements ionisants (à fraction unique : 1*28 Gy ; à multifraction : 4*12 Gy)
The landscape for radiation oncologists treating patients with metastatic disease has drastically changed during the past decade. With multiple seminal works in the arena of oligometastatic disease, the combination of stereotactic body radiation therapy (SBRT)/stereotactic ablative radiation therapy (SABR) became an important treatment modality for patients with metastatic disease. We learned that we can improve progression-free and overall survival and potentially begin flattening Kaplan-Meier curves in metastatic disease through the combination of SBRT/SABR and promising systemic therapies. In this issue of JAMA Oncology, Siva and colleagues report findings from the Trans Tasman Radiation Oncology Group (TROG) 13.01, a phase 2 randomized clinical trial that compared single-fraction vs multifraction SABR in patients with pulmonary metastases (Stereotactic Ablative Fractionated Radiotherapy Versus Radiosurgery for Oligometastatic Neoplasia to the Lung [SAFRON] II). The study included 90 patients with a total of 133 pulmonary oligometastases (defined as ≤3 cm) with a maximum size of 5 cm and a noncentral location who were randomized to a single-fraction treatment of 28 Gy or a multifraction treatment of 48 Gy delivered at 12 Gy per fraction, with biologic effective doses at 10 Gy (BED10) of 106 Gy in the single-fraction arm and 105 Gy in the multifraction arm. The primary end point was grade 3 or higher treatment-related adverse events within 1 year of treatment completion. The study found no difference in grade 3 or higher toxic effects, which were overall relatively low at 3% for the multifraction arm and 5% for the single-fraction arm. Οne grade 5 toxic effect occurred in a patient who had underlying, unrecognized interstitial lung disease and had 3 lesions treated with multifraction SABR and unfortunately developing pneumonitis 3 months after treatment. The investigators additionally found no difference in freedom from local failure, disease-free survival, and overall survival between the 2 fractionation schemes. An additional novelty of this work is their analysis on the immunogenic effects of SABR in which they demonstrated expected changes in T-regulatory cells, cytotoxic T-lymphocyte–associated antigen, and programmed cell death 1 expression, which all had increased expression levels after SABR; differences of expression between the single-fraction and multifraction arms appeared to be similar. Finally, patient-reported outcomes appeared similar between the 2 groups. The authors concluded that both single-fraction and multifraction treatments are safe and effective, with the single-fraction treatment potentially being more convenient for patients.
JAMA Oncology , éditorial en libre accès, 2020