Extranodal natural killer/T-cell lymphoma, nasal type: the significance of radiotherapeutic parameters.

BACKGROUND The objective of this study was to investigate the correlation between local recurrence and radiotherapeutic parameters, including dose and RT radiotherapy (RT) field. METHODS The current study included 35 patients who were diagnosed with immunohistochemically confirmed nasal natural killer (NK)/T-cell lymphoma between 1976 and 2004. There were 21 males and 14 females, and they ranged in age from 18 years to 76 years (median, 51 yrs). The primary tumor originated in the nasal cavity in 28 patients, and 32 patients had Stage I disease. Seventeen patients received treatment solely with RT, and the remaining 18 patients received a combination of chemotherapy and RT. The median tumor dose was 50 grays (Gy) (range, 22–60 Gy). Twenty-seven patients received RT to include all macroscopic lesions, all paranasal sinuses, the palate, and the nasopharynx. Eight patients received RT to all macroscopic lesions with generous margins. RESULTS A complete remission (CR) or a CR/unconfirmed was achieved in 28 patients (80%). The 5-year overall survival (OAS) rate, disease-free survival (DFS) rate, and local control probability (LCP) were 47.3%, 42.9%, and 65.2%, respectively. Patients who received RT only to macroscopic lesions fared less well in terms of LCP (LCP 5 years, 71.9% vs. 41.7%; P = 0.007). The difference in RT field also affected both the OAS rate and the DFS rate. Patients who received RT doses ≥ 50 Gy tended to achieve favorable local control. CONCLUSIONS In the management of nasal NK/T-cell lymphoma, the RT field affected treatment outcomes. RT doses ≥ 50 Gy resulted in favorable local control. Cancer 2006. © 2005 American Cancer Society.