A Phase II Study of Stereotactic Body Radiotherapy and Stereotactic Body Proton Therapy for High-Risk Medically Inoperable Early-Stage Non-Small Cell Lung Cancer
Mené sur 19 patients atteints d'un cancer du poumon non à petites cellules, de stade précoce, à haut risque de récidive et inopérable (durée médiane de suivi : 32 mois), cet essai de phase II compare l'efficacité, du point de vue du contrôle de la maladie et de la survie globale à 3 ans, et la toxicité d'une radiothérapie corporelle stéréotaxique (radiothérapie conformationnelle 3D ou radiothérapie avec modulation d'intensité) et d'une protonthérapie corporelle stéréotaxique
Purpose : To report the feasibility of conducting a randomized study to compare the toxicity and efficacy of stereotactic body radiotherapy (SBRT) versus stereotactic body proton therapy (SBPT) for high-risk medically inoperable early-stage non-small cell lung cancer (NSCLC). Methods and Materials : We randomly assigned patients with medically inoperable NSCLC with high-risk features (centrally located or <5 cm-T3 tumor or isolated lung parenchymal recurrences) to SBRT or SBPT. Radiation dose was 50 Gy(RBE) in four 12.5-Gy(RBE) fractions prescribed to the planning target volume. SBRT was given using 3-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT), and SBPT was given using passive scattering. Consistency in patient setup was ensured with on-board cone-beam computed tomography for the SBRT group and with orthogonal X-rays for the SBPT group. Results : The study closed early owing to poor accrual, largely because of insurance coverage, and lack of volumetric imaging in the SBPT group. Ultimately, 21 patients were enrolled, and 19 patients who received 50 Gy in 4 fractions were included for analysis (9 SBRT, 10 SBPT). At a median follow-up time of 32 months, median overall survival (OS) time was 28 months in the SBRT group and not reached in the SBPT group. Three-years OS was 27.8% and 90%, 3-year local control (LC) was 87.5% (8/9) and 90.0% (9/10) and 3-years regional control (RC) was 47.6% (5/9) and 90% (9/10) in SBRT and SBPT respectively. One patient in the SBPT group developed grade 3 skin fibrosis. No patients experienced grade 4/5 toxicity. Conclusion : Poor accrual, due to lack of volumetric image and insurance coverage for proton therapy led to early closure of the trial and precluded accurate assessment of efficacy and toxicity. Comparable maturity of two radiotherapy modalities, particularly on-board image, and better insurance coverage for SBPT should be considered for the future studies.
http://www.redjournal.org/article/S0360-3016(18)30316-X/fulltext 2018