A comparative population-based analysis of sinonasal diffuse large B-cell and extranodal NK/T-cell lymphomas.

OBJECTIVE/HYPOTHESIS: Diffuse large B-cell lymphoma (DLBCL) and extranodal natural killer/T-cell lymphoma (ENKTL) are aggressive tumors. ENTKL is very rare in the United States and often affects the nasal cavity and paranasal sinuses; DLBCL, although more common, rarely occurs in these locations. Our study aims to compare incidence and survival of these lymphomas in the sinonasal cavity.

STUDY DESIGN: Retrospective analysis of the United States National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) registry.

METHODS: The SEER database was searched for patients diagnosed with sinonasal ENKTL and DLBCL between 1973 and 2011. Data analyzed included patient demographics, incidence, treatment modality, and survival.

RESULTS: Three hundred and twenty-eight sinonasal ENKTL (SN-ENKTL) cases and 1,054 sinonasal DLBCL (SN-DLBCL) cases were identified. The mean ages at diagnosis for SN-ENKTL and SN-DLBCL were 51.7 and 67.8 years, respectively (P = 0.0001). Overall 1-, 5-, and 10-year disease-specific survival (DSS) rates for SN-DLBCL were 85.5%, 63.5%, and 44.0%, compared to 66.4%, 30.9%, and 9.2% for SN-ENKTL, respectively (P < 0.0001). For patients matched for stage, age, and treatment modality, the 1-, 5-, and 10-year DSS for the SN-DLBCL group was 94.4%, 72.8%, and 46.8%, respectively, whereas the respective survival rates for the SN-ENKTL group were 77.6%, 38.4%, and 13.9%, respectively (P < 0.0001 at each time interval).

CONCLUSIONS: To our knowledge, this study represents the only population-based comparison between SN-DLBCL and SN-ENKTL. SN-DLBCL has a better prognosis regardless of gender, stage, treatment modality, and age.

LEVEL OF EVIDENCE: 2b.