This study evaluated the clinical outcomes of stereotactic body radiotherapy (SBRT) for both pathologically diagnosed (PD) and clinically diagnosed (CD) early-stage non-small cell lung cancer (NSCLC) and explored the significance of accurate expert computed tomography (CT) interpretation.

We retrospectively analyzed 95 patients with early-stage NSCLC who received SBRT at our institution. Patients were classified into CD and PD groups. Two chest radiologists retrospectively interpreted the pre-SBRT CT images to determine the tumor subtype and probability of malignancy (PM). Clinical findings, CT features, and treatment outcomes were compared between the two groups. The survival rate of the CD group was analyzed separately according to the PM grade.

Median overall survival for the CD and PD groups was 6.0 and 5.4 years (P = 0.57), respectively. Median cause-specific survival was 10.2 years in the CD group and not reached in the PD group (P = 0.76). In the CD group, lung cancer mortality was lower in the low PM group (25% [1 of 4]) than in the high PM group (47.4% [9 of 19]).

It may be desirable to evaluate the PM of the nodule using expert CT interpretation to decide whether SBRT is indicated in CD early-stage NSCLC.