Orbital Non-Hodgkin Lymphoma: a single institution analysis on therapy outcomes and therapy induced Second Primary Malignancies

Introduction: Primary non-Hodgkin´s Lymphoma (NHL) of the orbit is a rare presentation and radiation therapy (RT) is considered the standard treatment for initial stage disease and low-grade NHL. Radiation therapy side effects include cataracts, dry eye, retinopathy, and others. Another concern when using Radiation therapy is the risk of development of Second Primary Malignancies (SPM). Objective: To evaluate prognostic factors, outcomes and complications including SPM development of patients treated for orbital primary NHL with Chemotherapy (CT), RT or Combined modality. Methods: From 01/04 to 12/19, we identified 30 patients diagnosed with primary orbital NHL treated at HSP/UNIFESP. Inclusion criteria were: age ≥ 18 years with biopsy-proven diagnosis of orbit NHL with a minimum follow-up of six months. RT dose ranged from 20 to 36 Gy. CT was delivered with different multidrug chemotherapy. Data on Progression free-survival (PFS), SPM free-survival (SPMFS) and Overall Survival (OS) were analyzed using the Kaplan-Meier method. Prognostic factors were compared using Pearson Chi-square or Fisher’s exact test. Results: The median follow up was 54 months and median age was 63,5 years. Five and10 year PFS was 86,4% and 71,28%, respectively. OS was 91,58% and 83,94% in 5 and 10 years, respectively. The prognostic factors that impacted on OS on univariate analysis were disease stage (log-rank: p=0,002) (Fig. 5), Age ≥ 65(log-rank, p=0,008) and site of disease (log-rank: p=0,042). SPM incidence was 26,7%, with a median time for SPM appearance of 53,5 months. SPMFS was 71,55% in 5 and 63,6% in 10 years. Neither RT (p=0,440) and CT (p=0,226) were associated with higher SPM incidence. Higher disease stage (stages III-IV) was associated with augmented SPM incidence (p=0,037). SPMs did not impact on OS (p=0, 065). Conclusion: Orbital NHL are adequately treated with RT and CT with good results and acceptable toxicity. Age, disease stage and eyelid as the site of the disease were the main predictors for overall survival. RT and CT were not associated with increased rate of SPMs, although we observed a higher than expected SPM incidence in our population. We believe more studies with larger number of patients would be helpful to elucidate the predictive factors associated with SPM development and the impact of SPM on survival in patients treated for NHL of orbit.