Tumor control and toxicity for common SBRT dose-fractionation regimens in Stage I NSCLC
A partir de données portant sur 600 patients atteints d'un cancer du poumon non à petites cellules de stade I, cette étude évalue l'efficacité, du point de vue du contrôle de la tumeur, et la toxicité d'une radiothérapie stéréotaxique en fonction de la dose biologique équivalente délivrée
Résumé en anglais
Purpose : While a biologically equivalent dose (BED) of 100-105 Gy10 has historically been considered adequate for optimal local control with stereotactic radiation (SBRT) in early stage non-small cell lung cancer (ES-NSCLC), randomized data is lacking. We sought to examine the impact of SBRT dose on outcomes in a large single-institution series.
Methods and Materials : We reviewed 600 patients treated from 2003-2012 for ES-NSCLC. SBRT dose was at physician discretion based on tumor size and location. Peripheral tumors were treated to 60 Gy in 3 fractions (homogeneous planning), 48-50 Gy in 4-5 fractions, or 30-34 Gy in 1 fraction. Central tumors were treated to 50 Gy in 5 fractions, 60 Gy in 8 fractions, or 50 Gy in 10 fractions. Patient, tumor, and treatment factors were assessed for their impact upon patterns of failure, toxicity, and survival.
Results : SBRT dose of 54-60 Gy in 3 fractions was associated with a statistically significant lower local failure (LF) (4.3% at 2-years) compared to 30-34 Gy in 1 fraction (21%), 48-50 Gy in 4-5 fractions (15.5%), and 50-60 Gy in 8-10 fractions (13.3%). Lower pre- SBRT hemoglobin and higher PET SUV were also associated with LF. Nodal failure, distant failure, and overall survival were similar between fractionation groups. Pulmonary toxicity (crude rate, any grade) was slightly higher for 3 fractions (5.0%) compared to 1 (3.2%) or 4-5 fractions (3.8%). Chest wall toxicity was also higher for 3 (23.7%) compared to 1 (8.6%) or 4-5 (7.7%) fraction regimens.
Conclusions : While higher BED SBRT (150-180 Gy10) may be associated with slightly lower LF, it was also associated with mildly increased toxicity, and no difference in other patterns of failure or overall survival.
