Background: Differentiation between primary ocular adnexal mucosa-associated lymphoid tissue (POA-MALT) lymphoma and reactive lymphoid hyperplasias sometimes may be difficult. We have examined the treatment-associated mortality of POA-MALT lymphoma after confirmed diagnosis and evaluated their proper treatments.
Patients and methods: From 1991 through 2016, cases of POA-MALT lymphoma were retrospectively analyzed based on their pathological and molecular/immunological diagnoses.
Results: A total of 78 cases with POA-MALT lymphoma with a median age of 66 years were analyzed over median/mean observations of 6.4/7.1 years. Forty-four patients (56%) were diagnosed with IgH gene clonality and 10 patients (13%) were diagnosed with flow cytometric analysis in addition to the pathological decision. The rest (24 patients, 31%) were diagnosed employing pathological decisions of hemato-pathologists and clinical decisions. All patients, except cases of watchful waiting, achieved complete remission. After initial treatment, 68 patients (87%) presented disease-free during the observation period. As treatment, a radiotherapy-based strategy was followed with 15 patients (19%, group A). Immuno-chemotherapy was administered to 24 patients (31%, B). Surgical extraction only was selected for 36 patients (46%, C). Watchful waiting was selected with three patients (4%). Recurrence after the initial treatment was found in one patient (7%) out of A, in three patients (13%) out of B, and in six patients (17%) out of C, respectively. Progression-free survivals at 5 and 10 years were 100 and 100% in A, 95 and 75% in B, and 88 and 81% in C, respectively. The recurrence rates between the patients who were diagnosed with only pathological decision (n = 24) and the patients who were diagnosed with molecular and immunological procedures (n = 54) did not show any statistical differences.
Conclusion: Our results indicate that radiotherapy-based treatment strategies for patients with POA-MALT lymphoma show a low rate of recurrence and may improve their prognosis even after the accurate diagnosis. However, contamination of the cases with reactive (polyclonal) lymphoid hyperplasia into those with MALT lymphoma should be carefully removed to avoid unnecessary treatment for malignancies that do not exist.
Keywords: Monoclonality; Non-Hodgkin lymphoma; POA-MALT lymphoma; Radiotherapy; Treatment-associated mortality.