The Outcomes of Three-Dimensional Conformal Radiotherapy for Early-Stage Non-Small-Cell Lung Cancer Patients Eligible and Ineligible for Stereotactic Body Radiotherapy

Introduction: Stereotactic body radiotherapy (SBRT) in early-stage non-small-cell lung cancer (NSCLC) results in promising outcomes, comparable with the outcomes of surgery. However, not all such patients are good candidates for this treatment. We conducted a retrospective evaluation of the outcomes of three-dimensional conformal radiotherapy (3D-CRT) in patients with stage I/II NSCLC with a special focus on the outcomes of patients who were eligible for SBRT but received 3D-CRT due to the unavailability of the former. Material and methods: We evaluated 132 consecutive patients with stage I/II NSCLC who had received radical 3D-CRT between 1998 and 2009. As various radiotherapy schedules had been used, biologically equivalent doses (BEDs) were calculated for all the patients. A total of 68 patients were eligible for SBRT (peripheral T1-3 N0 tumours < 5 cm in diameter). Overall survival (OS) and local progression free survival (LPFS) were estimated using Kaplan-Meier methodology for the entire study population and for the groups eligible and ineligible for SBRT. Univariate and multivariate analyses were performed for the prognostic factors. Results: Median BED in the study population was 74 Gy (58–82 Gy). Patients eligible for SBRT had a significantly lower gross tumour volume (GTV) than the other patients (p < 0.00001). Three-year OS and LPFS were 37% and 50%, respectively. When we compared patients eligible for SBRT and those ineligible for SBRT the only significant difference was for three-year LPFS (58% v. 35%, p = 0.04). Multivariate analysis showed that only GTV, performance status and tumour stage were significantly correlated with local curability. Conclusions: We showed an improved local control following 3D-CRT in patients eligible for SBRT compared to the other patients. However, also in these cases, local control was inferior compared to the outcomes of SBRT reported in the literature.