Radiation Therapy Dose for Limited-stage Extranodal Marginal Zone Lymphomas of the Mucosa-associated Lymphoid Tissues of the Stomach: A Meta-analysis.

Purpose: To compare the outcomes of 2 standard radiation therapy (RT) doses for limited-stage gastric extranodal marginal zone lymphoma (EMZL) of the mucosa-associated lymphoid tissues.

Methods and materials: A database search was performed to identify articles published from database inception to August 31, 2023. Based on the current standard dose of 24.0 to 30.0 Gy, doses of approximately 30.0 Gy were classified as standard dose (SD), while those of approximately 24.0 Gy were classified as low dose (LD). Pooled estimates of the complete remission (CR) and local recurrence (LR) rates were calculated and compared.

Results: Data from 1072 patients across 30 included studies were analyzed. SD was used in 28 studies (n = 987), while LD was used in 6 studies (n = 85), and both regimens were used in 4 studies. In all included studies, the CR rate was 0.96 (95% CI, 0.94-0.97), and the LR rate was 0.05 (95% CI, 0.04-0.06), showing no significant between-study heterogeneity (τ² = 0 and I² = 0% for both; P = .8447 and .9998, respectively). SD and LD resulted in no significant differences in the CR rates (0.96 [95% CI, 0.94-0.97] vs 0.96 [95% CI, 0.89-0.99]; P = .9174) or LR rates (0.05 [95% CI, 0.04-0.06] vs 0.03 [95% CI, 0.01-0.10]; P = .5495).

Conclusions: Both the SD and LD groups achieved excellent CR and LR rates. These results indicate that the RT dose for limited-stage gastric EMZL may be safely de-escalated without compromising local tumor control.