In this new era of three-dimensional treatment planning, more precise delivery methods are available allowing for dose escalation to the target volume without excessive dose being deposited in normal tissues. The RTOG has completed an extensive dose escalation study of conventionally fractionated three-dimensional conformal radiotherapy (3D-CRT) for NSCLC for stages I, II, and III disease as long as all detectable tumor can be encompassed by the radiation therapy fields including both primary tumor and regional lymph nodes.22 No mechanism for minimizing lung and tumor movements was utilized. One hundred and seventy-nine patients were treated with radiation doses escalated to as high as 90.3 Gy. Patients were stratified within each dose level according to the percentage of the total lung volume that received >20 Gy with the treatment plan (V20). For patients receiving radiation alone or radiation following induction chemotherapy, data from RTOG 9311 established that the radiation dose could be safely escalated using 3D-CRT techniques to 83.8 Gy for patients with V20 values of <25% and to 77.4 Gy for patients with V20 values between 25% and 36%, using fraction sizes of 2.15 Gy. Excess mortality was observed at 90.3 Gy with two dose-related deaths. The incidence of grade 3 or higher acute toxicity is less than 10%; however, grade 3 or higher late toxicity was approximately 15%.