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

ABSTRACT

BACKGROUND: Diffuse 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. METHODS: To 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. RESULTS: We 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. CONCLUSIONS: Compared 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.