When do we need central nervous system prophylaxis in patients with extranodal NK/T-cell lymphoma, nasal type?

The incidence and risk factors of central nervous system (CNS) invasion is still unclear in extranodal natural killer (NK)/T-cell lymphoma, nasal type.

We analyzed 208 patients to study the clinical features and outcomes of CNS disease in extranodal NK/T-cell lymphoma.

Twelve patients (5.76%, 12/208) experienced CNS disease during treatment or follow-up period (median 11.62 months, range 0.2-123.2 months). The clinical variables associated with CNS disease were Ann Arbor stage III/IV (15.87%, P <0.001), regional lymph node involvement (10.41%, P = 0.006), group III/IV of NK/T-cell lymphoma prognostic index (NKPI; 10.20%, P = 0.003), high/high-intermediate international prognostic index (9.30%, P = 0.072) and extra-upper aerodigestive primary sites (9.75%, P = 0.008). In multivariate analysis, NKPI retained the strongest statistical power to predict CNS disease (P = 0.007, relative risk 9.289, 95% confidence interval 1.828-47.212) in extranodal NK/T-cell lymphoma.

Despite extranodal NK/T-cell lymphoma frequently involves paranasal sinus, a routine CNS evaluation and prophylaxis do not seem to be necessary in NKPI group I or II patients due to a very low incidence. Nevertheless, CNS prophylaxis should be considered in NKPI groups III and IV.