Impact of Corticosteroid Administration on Outcomes Following Stereotactic Ablative Radiotherapy for Non–small-cell Lung Cancer

Introduction: Radiotherapy produces immune-promoting effects, which may be blunted by the delivery of corticosteroids (CS). We thus aimed to evaluate the impact of CS use on recurrence and survival outcomes of patients with early stage non–small-cell lung cancer treated with stereotactic ablative radiotherapy (SABR). Materials and Methods: A prospectively registered database of patients with stage I to II (T1-3N0M0) stage non–small-cell lung cancer treated with SABR from 2004 to 2015 was queried. Concurrent CS administration was defined as receipt of CS within 2 days of the SABR course. Statistics included Kaplan-Meier survival analysis, Cox proportional hazards modeling, and cumulative incidence analysis utilizing death as a competing risk. Results: Of 912 patients, 87 (9.5%) received CS with their SABR course. The most common agent was prednisone (64.4%). Indications for CS use were chronic obstructive pulmonary disease in 53 cases (60.9%), chemotherapy in 7 (8.0%), arthritis in 7 (8.0%), chronic pain in 4 (4.6%), transplant-related in 3 (3.4%), and “others” in 13 (14.9%; pneumonia, asthma, anemia, etc.). The median follow-up time was 59.3 months. Compared with patients who did not receive CS, receipt of CS was associated with poorer overall survival (P = .004). However, CS administration was not associated with worse time to progression (P = .766) or any recurrence when using death as a competing risk (local P = .119, regional P = .449, distant P = .847, and any recurrence P = .708). Toxicity rates were not statistically different between cohorts. Conclusions: These data do not suggest increased recurrence rates when patients undergoing SABR are administered corticosteroids. However, owing to limitations of retrospective analyses, individualized judgment is still recommended. Radiotherapy produces immune-promoting effects, which may be blunted by the delivery of corticosteroids. When analyzing 912 patients with T1-3N0M0 non–small-cell lung cancer treated with stereotactic ablative radiotherapy, corticosteroid administration (defined as within 2 days of the stereotactic ablative radiotherapy course) was not associated with an increased recurrence rate.