Diagnosis, treatment, and prognosis of primary intraocular lymphoma: Single‐center real‐world clinical experience

BACKGROUND: The diagnosis and management of primary intraocular lymphoma (PIOL) remain challenging. This study identified factors indicative of PIOL, described treatment outcomes, and determined modalities to prevent relapse. METHODS: We included 21 PIOL‐diagnosed patients, seven via cytology, 12 via genetic evaluation, and two via interleukin (IL) level measurements, who underwent vitrectomy and received local intravitreal methotrexate (IV‐MTX) injection. Clinical outcomes, including treatment response and relapse, were compared between patients receiving IV‐MTX alone (n = 13) or IV‐MTX with systemic high‐dose methotrexate (HD‐MTX) as prophylaxis (n = 8). RESULTS: Twelve ophthalmologic and eight central nervous system (CNS) relapse cases within a median of 20.3 and 11.6 months were shown, regardless of the treatment modalities, with a median progression‐free survival of 21.3 (95% confidence interval, 9.5–36.7) months. There was no difference in demographic characteristics between the two groups, except with the poorer performance status in patients in the HD‐MTX prophylaxis group. Furthermore, patients demonstrated rapid elevations in the vitreous fluid IL‐10/IL‐6 cytokine ratio before ophthalmologic and CNS relapse. Therefore, diagnosis should be based on clinical signs and assisted by vitrectomy, cytologic, molecular, and cytokine studies. CONCLUSION: For PIOL, aggressive systemic treatment equivalent to that of primary CNS lymphoma (PCNSL) is recommended because solely HD‐MTX did not prevent or delay CNS relapse. To prevent PIOL relapse in the CNS efficiently, prospective trials with large numbers of patients and advanced therapeutic regimens are necessary. Furthermore, regular clinical follow‐up is crucial, and the IL‐10/IL‐6 ratio can help evaluate relapse promptly.