reported symptoms, while negative scores indicated more severe physician reported symptoms. Descriptive statistics, chi-square test, and Wilcoxon rank-sum test examine factors associated with discordance. Results: There were 499 symptom surveys from 44 patients. Concordance between PRO-CTCAE and CTCAE was associated with symptom severity (as reported by patients) for all domains (P < .001). Average PRO-CTCAE/CTCAE concordance was 91% for no symptoms, 29% for mild symptoms, 21% for moderate symptoms, and 7% for severe symptoms. Symptom assessment concordance was high at baseline due to lack of symptoms and decreased 37e83% during treatment. Posttreatment concordance was high (50%e92%), with the exception of xerostomia (36%). The majority of discordance was attributable to physician underreporting. Physician underreporting of symptom severity was statistically significant for patients older than 65 and for African Americans (Table). Conclusion: There is significant under-ascertainment of symptom severity by physicians for patients receiving head and neck radiation therapy. Age 65 and African American race were associated with discordance of patient physician symptom assessment. Author Disclosure: A. Falchook: Training course tuition fee waived;

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