Improved outcomes of localized diffuse large B‐cell lymphoma at the Waldeyer ring in comparison to the sinonasal area in the rituximab era

Abstract

BackgroundDiffuse large B‐cell lymphoma (DLBCL) of the head‐and‐neck area primarily involves the Waldeyer ring (WR) and sinonasal area (SN). However, the differential clinical outcomes between patients with WR‐DLBCL and those with SN‐DLBCL in the rituximab era remain unclear.MethodsTo avoid confounding factors contributed by advanced DLBCL with WR and SN involvement, we assessed the clinical outcomes of patients with stage I/II WR‐DLBCL and SN‐DLBCL and compared them with those having corresponding stages of DLBCL in the lymph nodes but without other extranodal involvement (LN‐DLBCL) in the same period. We compared the patients' clinical characteristics, treatment modalities, event‐free survival (EFS), and overall survival (OS) among the three subgroups.ResultsWe analyzed 67, 15, and 106 patients with WR‐DLBCL, SN‐DLBCL, and LN‐DLBCL, respectively, between January 2000 and December 2019. All patients received front‐line rituximab‐based regimens, and > 80% received rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone‐based regimens. More patients with SN‐DLBCL had revised International Prognostic Index (R‐IPI) score 3 (27%) when compared with those with WR‐DLBCL (7%) and those with LN‐DLBCL (10%, p = 0.181). Patients with WR‐DLBCL, LN‐DLBCL, and SN‐DLBCL had 5‐year EFS and OS rates of 80.7%, 59.5%, and 41.9% (p = 0.021) and 83.7%, 70.8%, and 55.8% (p = 0.032), respectively. Compared to patients with LN‐DLBCL, those with WR‐DLBCL also had a significantly favorable 5‐year EFS rate (p = 0.021) and 5‐year OS rate (p = 0.023). Three of the 15 patients with SN‐DLBCL experienced lymphoma recurrence in the brain after front‐line treatment. In multivariate analyses, R‐IPI scores of 1–2 and 3 served as significantly poor prognostic factors for patients with poor EFS and OS.ConclusionsCompared to patients with LN‐DLBCL, patients with WR‐DLBCL receiving front‐line rituximab‐based treatments had favorable clinical outcomes; however, patients with SN‐DLBCL had worse clinical outcomes. Further studies on molecular prognostic factors and treatment strategies for SN‐DLBCL are warranted.