Acute phase response before treatment predicts radiation esophagitis in non-small cell lung cancer

Background and purpose: Radiation esophagitis (RE) represents an inflammatory reaction to radiation therapy (RT). We hypothesized that aspects of the physiologic acute phase response (APR) predicts RE.

Material and methods: We retrospectively analyzed 285 patients with non-small cell lung cancer (NSCLC) treated with definitive radiation. The primary analysis was the association of pretreatment lab values reflective of the APR with symptomatic (grade ⩾ 2) RE. Univariate and multivariate odds ratios (ORs) were calculated to test associations of clinical and pretreatment lab values with RE. Optimal cutpoints and multivariable risk stratification groupings were determined via recursive partitioning analysis.

Results: Pretreatment platelet counts were higher and hemoglobin levels lower in patients who developed RE (P<0.05). Based on these two pre-treatment risk factors, an APR score was defined as 0 (no risk factors), 1 (either risk factor), or 2 (both risk factors). APR score was significantly associated with RE in both univariate (OR = 2.3 for each point, 95% confidence interval [CI] 1.5-3.4, P = 0.001) and multivariate (OR = 2.1, 95% CI 1.3-3.4, P = 0.002) analyses.

Conclusions: The APR score may represent a novel metric to predict RE. However, pending validation in an independent dataset, caution is advised when interpreting these results given their retrospective and thus exploratory nature.