Preliminary results of a phase n prospective clinical study of early-stage nasal NK/T-cell lymphoma with extended involved-field intensity-modulated radiotherapy

Objective: To investigate the feasibility of the scheme of target volume delineation with extended involved-field intensity-modulated radiotherapy (IMRT) for patients with early-stage nasal NK/T-cell lymphoma (NC-NKTL). Methods: Twenty-one patients with stage I_E-II_E NC-NKTL were treated with short-course chemotherapy combined with radiotherapy from 2011 to 2013. The majority of patients received the GELOX regimen. All patients received extended involved-field IMRT with a dose of 54.6 Gy in 26 fractions for gross tumor volume, 50.7 Gy in 26 fractions for high-risk clinical target volume (CTV), and 45.5 Gy in 26 fractions for low-risk CTV. The dose distribution, short-term treatment outcomes, and adverse reactions were analyzed. Results: The 2-year sample size was 12. The 2-year follow-up rate was 100%. The 2-year local control rate (LRC) was 100%. The 2-year overall and progression-free survival rates wee 90.5% and 90.5%, respectively. The median coverage rates of planning target volumes with 90% of the prescribed doses of 54.6 Gy, 50.7 Gy, and 45.5 Gy were 99.8%, 99.6%, and 99.7%, respectively. No grade 3 or 4 adverse reactions were observed in patients. Conclusions: The scheme of target volume delineation and dose configuration in our study not only achieves excellent target volume coverage, but also reduces adverse reactions in patients, which achieves a 2-year LRC ideal for patients with early-stage NC-NKTL. (authors)