Xiaoqin Ji,1,* Xuebing Shi,2,* Jun Hu,3 Wanrong Jiang,3 Bin Zhou,3 Houlong Zhou,3 Xi Yuan,3 Yikun Li,3 Hua Huang,3 Jiasheng Wang,3 Wei Ding,3 Yong Wang,4 Xiangdong Sun3 

1Department of Radiation Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, People’s Republic of China; 2Department of Radiation Oncology, Nanjing Jiangbei Hospital, Nanjing, People’s Republic of China; 3Department of Radiation Oncology, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, People’s Republic of China; 4Department of Outpatient Clinic, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Yong Wang; Xiangdong Sun, Email 292917354@qq.com; sunxd_81@126.com

Purpose: The objective of this study was to compare the clinical outcomes of stereotactic body radiation therapy (SBRT) in elderly patients aged 65 or older with clinical stage I–II non-small-cell lung cancer (NSCLC), specifically examining the differences between centrally located lung tumors and peripherally located lung tumors.
Methods: From April 2009 to January 2020, a total of 136 patients with 136 tumors (65 central, 71 peripheral; NSCLC) at an early stage (T1-3N0M0) were treated with SBRT at a single institution. Central/peripheral location was assessed retrospectively on planning CT scans. A propensity score matching analysis was utilized to compare the two groups. In addition, the prognosis and related toxicity were compared between the two study arms.
Results: A total of 33 central tumors and 33 peripheral tumors were matched and analyzed. The results showed no significant differences in overall survival (OS) and progression-free survival (PFS) between the two groups. The 2-year OS was 71.88% (95% CI, 57.87%-89.27%) in the central lung cancer group, while it was 93.94% (95% CI, 86.14%-100.00%) in the peripheral lung cancer group (P=0.462). The 2-year PFS was 43.75% in the central lung cancer group, while it was 78.79% in the peripheral lung cancer group (P=0.279). Further subgroup analysis indicated that the location of peripheral tumor have a positive impact on OS in patients with adenocarcinoma. The occurrence of local failure, regional failure, or distant failure was comparable between central and peripheral tumors. There was no statistically significant difference in toxicity between the central and the peripheral tumor groups.
Conclusion: The outcomes of SBRT for central tumors versus peripheral lung tumors in elderly patients with early-stage NSCLC were similar. SBRT demonstrated a similar level of safety in terms of toxicity for both central and peripheral lung tumors.

Keywords: Non-small cell lung cancer, stereotactic body radiation therapy, central lung cancer, elderly patients, propensity score matching