Feasible Optimization of Stereotactic Ablative Radiotherapy Dose by Tumor Size for Stage I Non-small-cell Lung Cancer.

Sumin Lee; Si Yeol Song; Su Ssan Kim; Wonsik Choi; Hyoung Uk Je; Geum Mun Back; Byungchul Cho; Seong-Yun Jeong; Eun Kyung Choi; Lee, Sumin; Song, Si Yeol; Kim, Su Ssan; Choi, Wonsik; Je, Hyoung Uk; Back, Geum Mun; Cho, Byungchul; Jeong, Seong-Yun; Choi, Eun Kyung

<bold>Introduction: </bold>The purpose of this study was to assess the effect of dose escalation of stereotactic ablative radiotherapy (SABR) by investigating the long-term clinical outcomes of SABR for stage I non-small-cell lung cancer (NSCLC).<bold>Methods: </bold>A retrospective analysis was performed on a total of 169 patients with 178 lesions of stage I NSCLC treated with SABR at a single institution from June 2000 to May 2015. The standard dose scheme for SABR was 48 Gy in 4 fractions during the early period of the analysis, but it was escalated to 60 Gy in 4 fractions from June 2009. All failures were recorded over the follow-up period.<bold>Results: </bold>Median follow-up time was 32 months. The 5-year overall survival rate was 46.7%, and the actuarial local control rate was 79.3%. Tumor size was an independent prognostic factor for survival. No relapse occurred in tumors ≤ 2 cm irrespective of SABR dose. Escalated doses of approximately 60 Gy in 4 fractions (biologically effective dose [BED] = 150 Gy10) achieved higher local control compared with 48 Gy in 4 fractions (BED = 106 Gy10) (76.2% vs. 60.6%) at 5-year follow-up (P = .022) in tumors > 2 cm. There were no differences in treatment-related toxicities between the dose groups. Major failures consisted of distant metastasis to another lung parenchyma.<bold>Conclusion: </bold>SABR provides satisfactory long-term local control and high overall survival in medically inoperable stage I NSCLC. Tumors ≤ 2 cm had no local recurrence regardless of dose; whereas for tumors > 2 cm, an escalated BED of approximately 150 Gy10 provided significantly higher local tumor control.

SOUTH Korea; CANCER relapse; ANTHROPOMETRY; COMPARATIVE studies; LUNG cancer; LUNG tumors; RESEARCH methodology; MEDICAL cooperation; RADIATION doses; RADIOSURGERY; RESEARCH; SURVIVAL; TUMOR classification; EVALUATION research; RETROSPECTIVE studies; PREVENTION

Clinical Lung Cancer, 2018, Vol 19, Issue 2, pe253

1525-7304

Academic Journal

10.1016/j.cllc.2017.11.001