A Phase II Trial of Midtreatment PET-CT Adapted Radiation Therapy With Concurrent Chemotherapy in Patients With Inoperable/Unresectable Non-Small Cell Lung Cancer (NSCLC)

Abstract

Purpose/Objective(s): We hypothesized that adapting radiation therapy (RT) by targeting high dose radiation to the FDG‐avid tumor identified by mid‐treatment FDG‐PET would improve local tumor control of non‐small cell lung cancer (NSCLC). Materials/Methods: This was a phase II trial for patients with inoperable/ unresectable, stage I‐III NSCLC. Conformal RT was given in 30 daily fractions. RT dose was individualized to a fixed risk of lung toxicity (grade >2) and adaptively escalated to the residual tumor defined on mid‐treatment FDG‐PET up to a total dose of 86 Gy. Selected patients with stage IIIII disease also received concurrent weekly carboplatin plus paclitaxel followed by three cycles of consolidation carboplatin plus paclitaxel. The primary endpoint was local tumor control, measured as overall localregional tumor control (LRTC) and local‐regional progression free survival (LR‐PFS). The trial was designed to achieve 2‐year local tumor control of 54%, which would be a 20% improvement from our prior clinical trial experience with 63‐69 Gy in a similar patient population. Results: The trial reached its accrual goal of 42 patients: median age 63 years (range 45‐83); male 28 (67%); smoker/former smoker 39 (93%); stage III 39 (92%). Median physical tumor dose delivered was 83 Gy (range 63‐86 Gy) in 30 daily fractions. Minimum and median follow‐up amongst patients who did not progress or die, were 24 and 47 months, respectively. The 2‐year rates of overall LRTC and LR‐PFS were 62% (43‐77%), and 38% (24‐52%), respectively. Median overall survival was 25 months (95% CI: 12‐32%) and the 2‐year overall survival rate was 52% (36‐66%). Conclusion: Adapting RT by targeting high‐dose radiation to the FDGavid region detected by mid‐treatment PET provides favorable localregional tumor control. RTOG 1106 is an ongoing trial to validate this finding in a randomized fashion.