Ultra-low-dose Radiotherapy in the Treatment of Ocular Adnexal Lymphoma: a Prospective Study

Purpose: This single-arm, prospective, exploratory study investigated the effectiveness of ultra-low-dose radiotherapy in the treatment of ocular adnexal lymphoma (OAL).

Patients And Methods: Patients with pathologically confirmed ocular adnexal low-grade non-Hodgkin lymphoma (predominantly mucosa-associated lymphoid tissue, MALT or follicular lymphoma) were included and treated with ultra-low-dose radiotherapy consisting of 2 successive fractions of 2 Gy at our institution between 2019 and 2021. Disease response was assessed clinically and radiographically within 4 months and at 3 to 6-month intervals after treatment. Data collected included rates of overall response, complete response (CR), partial response (PR), lesion size, and acute/chronic ocular toxic effects.

Results: Sixteen patients with median age of 63 years (range 23-86 years) were included in the study. The histological subtypes included MALT (11 patients; 69%); follicular lymphoma (2 patients; 12%); Lymphoid hyperplasia (3 patient, 19%). At a median follow-up time of 15.5 months (range 5.0-30.0 months), the overall response rate was 88%, with a CR rate of 75% (n = 12) and a PR rate of 13% (n = 2). The average lesion area was reduced from 117.9 ± 60.4 mm before radiation therapy to 38.7 ± 46.0mm at initial evaluation post radiation therapy (P = 0.002, n = 16), and to 8.5 ± 21.2 mm (P < 0.001 compared with postoperative lesion area) in patients with response at one year (n = 11). Disease progression was noted in 2 patients (12%). The 1-year rates of local progression-free survivals (LPFS) and overall survival (OS) were 85% and 100%, respectively. No distant relapses were observed in any of the patients. No acute or late toxic effects were noted.

Conclusion: Ultra-low-dose radiotherapy in patients with OAL is associated with excellent local disease control and long-term survival with no significant acute or late toxicities.