Comparison of outcomes for patients with medically inoperable Stage I non–small-cell lung cancer treated with two-dimensional vs. three-dimensional radiotherapy

Purpose: This retrospective analysis was performed to assess the outcomes of three-dimensional (3D) conformal radiotherapy and two-dimensional (2D) planning.

Methods and Materials: Between 1978 and 2003, 200 patients with Stage I non–small-cell lung cancer (NSCLC) were treated with radiotherapy alone at M.D. Anderson Cancer Center. Eighty-five patients were treated with 3D conformal radiotherapy. For the 3D group, median age, radiation dose, and follow-up was 73 (range, 50–92), 66 Gy (range, 45–90.3 Gy), and 19 months (range, 3–77 months), respectively; and for the 2D group, 69 (range, 44–88), 64 Gy (range, 20–74 Gy), 20 months (range, 1–173 months), respectively. Overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS), locoregional control (LRC), and distant metastasis–free survival (DMFS) rates were analyzed.

Results: There was no statistically significant difference in patient and tumor characteristics between 2D and 3D groups, except the 3D patients were older (p = 0.006). The OS, DSS, and LRC rates were significantly higher in patients who were treated by 3D conformal radiotherapy. Two- and 5-year OS for the 3D group were 68% and 36%, respectively, and 47% and 10% in the 2D group (p = 0.001). DSS at 2 and 5 years for the 3D group were 83% and 68%, respectively, vs. 62% and 29% in the 2D group (p < 0.001). LRC rates at 2 and 5 years for patients in the 3D group were 77% and 70% and 53% and 34% in the 2D group (p < 0.001). On univariate analysis elective, nodal irradiation was associated with decreased OS, DSS, and LRC. On multivariate analysis, 3D conformal radiotherapy was associated with increased OS and DSS. Male sex, age ≥70, weight loss ≥5%, and tumor size ≥4 cm were associated with decreased OS and DSS.

Conclusions: This study demonstrates that 3D conformal radiotherapy improves outcomes in patients with medically inoperable Stage I NSCLC compared with 2D treatment and is an acceptable treatment for this group of patients.

Keywords:  Non–small-cell lung cancer , Three-dimensional conformal radiotherapy , Two-dimensional radiotherapy , Medically inoperable , Stage I