Tumor Size, Histology, and Survival After Stereotactic Ablative Radiotherapy and Sublobar Resection in Node-negative Non-small Cell Lung Cancer

Background: Although SABR is increasingly emerging as an alternative to surgery for node-negative non-small cell lung cancer, there is poor understanding of patients who may most benefit SABR compared to surgery. Objective: This study examined the relationship between tumor size and the comparative outcomes of SABR and sublobar resection in patients with node-negative non-small cell lung cancer. Results: A total of 59,949 patients met study criteria: 19,888 (33%) underwent SABR, 33,052 (55%) wedge resection, and 7009 (12%) segmental resection. In multivariable regression, a significant 3-way interaction was found between histology, tumor size, and type of treatment. After stratification by histology, a significant interaction between tumor size and treatment was preserved for patients with adenocarcinoma and squamous cell carcinoma. Sublobar resection was associated with greater survival compared to SABR for tumor sizes greater than 6 and 8 mm for patients with adenocarcinoma and squamous cell carcinoma, respectively. SABR was associated with similar survival compared to sublobar resection for patients with papillary and large cell histology. Conclusions: In this National Cancer Database analysis, sublobar resection was associated with greater survival compared to SABR for lesions >6or 8 mm in patients with adenocarcinoma or squamous cell carcinoma; however, SABR was associated with similar survival compared to sublobar resection in patients with aggressive tumors including papillary and large cell histology. Histologic diagnosis in patients with even small tumors may enable better treatment selection in those who cannot tolerate lobectomy.