Survival outcomes in primary orbital diffuse large B-cell lymphoma.

e19075 Background: Orbital diffuse large B-cell lymphoma is a rare entity accounts for less than 1% of all non-Hodgkin lymphoma cases. Large-scale studies describing and evaluating the effect of different type of treatments on survival outcome are lacking. Methods: The National Cancer Database (NCDB) was queried for patients diagnosed with primary orbital DLBCL between 2004 and 2020. All patients aged ≥ 18 years diagnosed with primary orbital DLBLC were included. We excluded patients with unknown chemotherapy and radiation therapy status or lost to follow-up (unknown vital status of last contact). Kaplan-Meier and multivariate Cox regression were used in the analyses. Results: The total cohort consisted of 404 patients with primary orbital DLBCL. Out of whom 233 (58%) were females, 326 (81%) were White non-Hispanic, 29 (7%) were White Hispanic and 16 (4%) were African Americans. 113 (28%) received chemotherapy only, 76 (19%) received radiation only, 113 (28%) received chemoradiation, 79 (20%) did not receive any treatment and 23 (6%) had unknown treatment status. The median age at diagnosis was 71 years (range 28-90). The median follow-up time was 132 months (95%CI 117-147), the median overall survival (mOS) for the whole cohort was 110 months (95%CI 82-138). Among patients with known treatment status and vital status of last contact (N=381), patient who received chemoradiation had significantly better mOS compared to patients who received radiation only (169 vs 67 months, P=0.002), but there was no statistically significant difference in mOS between chemoradiation and chemotherapy only (169 vs 124 months, P=0.068) or between chemotherapy only and radiation only (124 vs 67 months, P=0.213). On multivariate analysis, older age and Charlson-Deyo score of 2 were associated with worse OS (HR 1.072 95%CI 1.055-1.089; P<0.001, HR 2.292 95%CI 1.099-4.778; P=0.027, respectively). Compared to no treatment, only chemoradiation was associated with better OS (HR 0.509 95%CI 0.332-0.778; P=0.002), whereas chemotherapy only and radiation only did not add a survival benefit (HR 0.909 95%CI 0.598-1.381; P=656 and HR 0.766 95%CI 0.496-1.185; P=0.231). Conclusions: This large real-world analysis shows a survival benefit with combined treatment of chemoradiation in primary orbital DLBCL compared to single treatment modality.