Local Disease Control in Ocular Adnexal Lymphoproliferative Disorders: Comparative Outcomes of MALT Versus Non-MALT Histologies

The efficacy of involved field radiotherapy (IFRT) in the outcomes of patients with different subtypes of ocular adnexal lymphoproliferative disorder is lacking. We retrospectively analyzed and compared the outcomes of patients with mucosa-associated lymphoid tissue (MALT) and non-MALT ocular adnexal lymphoproliferative disorder after being treated with IFRT. Our results reveal that IFRT provided excellent disease control with superior failure-free survival in the MALT cohort when compared with the non-MALT cohort. Introduction Ocular adnexal lymphoproliferative disorders (OALDs) are almost exclusively of B-cell origin, with the majority being extra-nodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT). The comparative efficacy of involved field radiation therapy (IFRT) in MALT vs. non-MALT OALDs is not known. Materials and Methods We present a single-center, large cohort, retrospective study of the efficacy of IFRT in OALDs. Failure-free survival (FFS), complete remission, and local, regional, and distant failure were determined for 112 patients with MALT OALDs (n = 71) and non-MALT OALDs (n = 41) cohorts. Results Fifty-six patients with MALT OALD and 26 patients with non-MALT OALD received IFRT only (without any planned concurrent or sequential systemic chemothereapy or chemo-immunotherapies). Among the OALD cohorts treated with only IFRT, complete remission was achieved in 49 (87.5%) patients in the MALT cohort and 23 (88.4%) in the non-MALT cohort (P = .99). Clinically, resolution of symptoms occurred in 83.3% and 93.3% of the patients in the MALT and non-MALT cohorts, respectively. Local failure occurred in 4 (7.1%) patients in the MALT cohort, compared with 4 (15.3%) patients in the non-MALT cohort (P = .24). Regional failure (or extra-orbital failure) occurred in 5 (8.9%) patients in the MALT cohort and in 3 (11.5%) patients in the non-MALT cohort (P = .71). Distant failure was reported in 1 (1.7%) and 2 patients (7.6%) in the MALT and non-MALT cohorts, respectively (P = .18). The median follow-up of survivors was 5.1 years (range, 0.1-22.5 years) in the MALT cohort and 3.9 years (range, 0.1-22.9 years) in the non-MALT cohort. The 5-year and 10-year FFS was 95% (95% confidence interval [CI], 88%-100%) and 83% (95% CI, 70%-98%) for the ocular MALT and 67% (95% CI, 48%-94%) and 56% (95% CI, 34%-91%) for the non-MALT cohorts, respectively (log rank for P = .025). On multivariate analyses, age (hazard ratio [HR], 1.06; 95% CI, 1.10-1.12; P = .03), presence of non-MALT histology (HR, 13.9; 95% CI, 2.05-94.4; P = .007), and radiation dose < 30.6 Gy (HR, 5.27; 95% CI, 1.14-24.3; P = .03) were associated with worse FFS. The 5-year and 10-year overall survival was 92% (95%, CI 83%-100%) and 80% (95% CI, 66%-96%) for the MALT and 78% (95% CI, 61%-100%) and 62% (95% CI, 38%-100%) for the non-MALT cohorts, respectively (P = .80). Conclusion Our results reveal that IFRT provided excellent disease control with superior FFS in the MALT cohort when compared with the non-MALT group.