Dose-per-Fraction Escalation of Accelerated Hypofractionated Three-Dimensional Conformal Radiotherapy in Locally Advanced Non-small Cell Lung Cancer

Abstract

To determine the efficacy of accelerated hypofractionated three-dimensional conformal radiotherapy (3D-CRT) with dose-per-fraction escalation for treatment of stage III non-small cell lung cancer (NSCLC). Between 2001 and 2007, 173 patients with stage III NSCLC were treated using accelerated 3D-CRT and the simultaneous boost technique. Initially, the total dose of 56.7 Gy (including 39.9 Gy to the elective area) was delivered over 4 weeks in fractions of 2.7 Gy (1.9 Gy to the elective area). The dose-per-fraction escalation study commenced after the outcomes of 70 patients had been evaluated. The dose per fraction was increased from 2.7 through 2.8 Gy (level 1 escalation) to 2.9 Gy (level 2 escalation); the total dose increased, respectively, from 56.7 Gy through 58.8 Gy to 60.9 Gy. The dose to the elective area and the overall treatment time remained unchanged. Fit patients received two to three courses of chemotherapy before radiotherapy. The 2- and 3-year overall survival rates were 32 and 19%, respectively (median survival = 17 months). Of the patients, 7% had grade III acute esophageal toxicity and 6% had grade III or greater late pulmonary toxicity. Two of the nine patients who received the level 2 escalation (60.9 Gy) died of pulmonary toxicity. The study was terminated at a dose of 58.8 Gy and this schema was adopted as the institutional policy for treatment of stage III NSCLC. Although dose escalation with accelerated hypofractionated 3D-CRT was limited, the results and toxicity profiles obtained using this technique are promising.