Prospective Assessment of Patient-Reported Dry Eye Syndrome after Whole Brain Radiation

Abstract

Dry eye is not typically considered a toxicity of whole brain radiation (WBRT). We analyzed dry eye syndrome as part of a prospective study of patient-reported outcomes after WBRT. Patients with adequate mental status receiving WBRT (25-40 Gy in 10-20 fractions) for any diagnosis were enrolled on a study with dry mouth as the primary endpoint and dry eye syndrome as a secondary endpoint. Patients received 3-dimensional WBRT using opposed lateral fields. Per standard practice, the lacrimal glands were not prospectively delineated. Patients completed the Subjective Evaluation of Symptom of Dryness (SESoD, scored 0-4, higher representing worse dry eye symptoms) at baseline, immediately after WBRT (EndRT), one month (1M), three months (3M), and six months. Patients with baseline SESoD score of ≥3 (moderate dry eye) were excluded from this analysis. The dry eye endpoints analyzed were ≥1 point and ≥2 point increase in SESoD score at 1M. Lacrimal glands were retrospectively delineated with the aid of fused MRI’s and considered a single structure for dosimetric analysis. 100 patients were enrolled, 70 were eligible for analysis (30 patients were excluded, including 18 with baseline xerostomia, 4 who did not complete WBRT, 5 who did not complete any post-WBRT questionnaires, and 3 with baseline SESoD score of ≥3), and 54 were evaluable at 1M. Median bilateral lacrimal V20Gy was 79%. At 1M, 17 patients (32%) had a ≥1 point increase in SESoD score, and 13 (24%) a ≥2 point increase. At 3M, SESoD score was higher than baseline in 34% of evaluable patients. Lacrimal doses appeared to be associated with an increase in SESoD score at 1M of both ≥1 point (V10Gy: p=0.042, OR 1.09/Gy, V20Gy: p=0.071, OR 1.03/Gy) and ≥2 points (V10Gy: p=0.038, OR 1.15/Gy, V20Gy: p=0.063, OR 1.04/Gy). The proportion with increase in dry eye symptoms at 1M for lacrimal V20Gy ≥79% vs. <79% was 46% vs 15%, respectively, for ≥1 point SESoD increase (p=0.02), and 36% vs 12%, respectively, for ≥2 point SESoD increase (p=0.056). Dry eye syndrome appears to be a previously-unreported acute toxicity of WBRT. These data provide further support for the minimization of dose to secretory organs in patients receiving WBRT.