Analysis of risk factors for late relapse in early-stage extranodal nasal-type NK/T-cell lymphoma after treatment

Objective: To analyse the late relapse rate of stage I_E and II_E upper aerodigestive tract natural killer/T-cell lymphoma (UADT-NKTCL) in patients with a disease-free survival (DFS) of at least 5 years after treatment and the risk factors for late relapse. Methods: Between January 1983 and October 2007, 114 patients with stage I_E and II_E UADT-NKTCL received radiotherapy, chemoradiotherapy, or chemotherapy and had a DFS of at least 5 years after treatment. Of the 114 patients, 32 received radiotherapy alone, 80 received chemoradiotherapy, and 2 received chemotherapy alone. The Kaplan-Meier method was used to calculate the relapse rate, and the logrank test was used for survival difference analysis and univariate analysis of risk factors; the Cox regression model was used for multivariate analysis. Results: The follow-up rate was 100%. The number of patients followed-up were 79 at 10 years time. Twelve patients had late relapse (10.5%). 50%(6/12) patients with late relapse developed first locoregional relapse without systemic failure. The 10-year cancer-specific survival and cumulative probabilities of late relapse for entire patients were 92.2% and 8.4%, respectively. In univariate analysis, B symptoms, ECOG ≥ 2, chemotherapy alone and the dose of RT < 50 Gy were risk factors to incidence of late relapse (χ² = 4.00-11.14, P = 0.004-0.045). In multivariate analysis, B symptom was identified as independent correlative factor to incidence of late relapse (HR = 4.74 (95% CI = 1.33-16.93), χ² = 5.73, P = 0.017). Conclusions: Relapse occurs in a small proportion of patients with early-stage UADT-NKTCL who have a DFS of at least 5 years. Systemic symptoms at initial diagnosis is the independent risk factor for late relapse in UADT-NKTCL. (authors)