The Significance of Anatomic Sites in Diffuse Large B-Cell Lymphoma Recurrence

Objective: This study aimed to investigate the anatomic patterns and outcomes of first relapse in patients with diffuse large B-cell lymphoma (DLBCL). Materials and Methods: Between January 2015 and October 2024, a total of 1,047 newly diagnosed patients were evaluated, of which 139 patients who initially achieved complete remission (CR) but subsequently experienced relapse during follow-up were included in the analysis. Histological and imaging data were reviewed to determine the involvement of nodal regions, extranodal locations, and Waldeyer’s Ring at the time of relapse. Results: Our findings indicated that 112 patients (80.4%) presented with clinical manifestations that led to the diagnosis of recurrence. Two-thirds of patients relapsed within 18 months, and 85% within two years, with a median time to relapse of 9 months. Notably, 43.2% of patients experienced a change in the anatomic site of recurrence, which correlated with poorer clinical outcomes. The overall CR rate after relapse was 36.7% for those relapsing at previously involved sites, compared to just 10.0% for those with new site relapses. Higher CR rates were also observed in patients with relapses at previously involved sites from Waldeyer’s Ring (50% CR; 8 of 16) and extranodal lymphomas (40% CR; 8 of 20), compared to those relapsing at new sites (P=0.019 and P=0.006, respectively). Overall survival(OS) was significantly lower in patients with relapses at new sites (23.0 ± 4.2 months) compared to those at previously involved sites (41.8 ± 6.1 months). Kaplan-Meier analysis revealed significant differences in OS and progression-free survival(PFS) based on the site of relapse (P=0.043 and P=0.004, respectively). Patients experiencing relapses at new sites, particularly involving Waldeyer’s Ring and extranodal origins, had significantly poorer outcomes, with two-year OS rates of 16.7% and 8.3%, respectively (P=0.032 and P=0.006). Conclusions: Relapsed DLBCL tends to primarily affect previously involved sites, especially in patients with nodal origins. Recurrences at new sites are associated with poor outcomes, particularly when the initial anatomic sites were Waldeyer’s Ring and extranodal.