Efficacy of extended-field intensity-modulated radiotherapy for early-stage NK/T cell lymphoma / 中华放射肿瘤学杂志

ABSTRACT

Objective To evaluate the efficacy of extended-field intensity-modulated radiotherapy (IMRT) in the treatment of patients with early-stage NK/T cell lymphoma (NKTCL),and to examine the clinical characteristics and the effect of treatment factors on the prognosis of these patients.Methods The clinical data of 165 patients with early-stage NKTCL who underwent extended-field IMRT with (n=158,95.8%) or without chemotherapy (n=7,4.2%) were reviewed.Of these 165 patients,140(84.8%) received a radiation dose of ≥50 Gy to the primary lesion,and 25 patients (15.2%) received a radiation dose of<50 Gy.Most patients (n=147,89.1%) were treated with L-asparaginase-based chemotherapy regimens,whereas only 11 patients (6.7%) were treated with doxorubicin-based CHOP/CHOP-like regimens.In addition,109 patients (66.1%) received ≥4 cycles of chemotherapy.Locoregional control (LRC),overall survival (OS),and progression-free survival (PFS) rates were calculated using the Kaplan-Meier method,and the log-rank test was used for survival comparison and univariate prognostic analysis.A multivariate prognostic analysis was performed using the Cox model.Results The 5-year sample size 55.The 5-year OS,PFS,and LRC rates of all patients were 74.2%,72.5%,84.4%,respectively.The patients who received a dose of ≥50 Gy had a significantly higher 5-year LRC rate than those with<50 Gy (91.8% vs.39.7%,P=0.000).The 5-year OS was significantly higher in the low-risk early-stage group than in the high-risk early-stage group (P=0.002).For the high-risk early-stage NKTCL group,patients who received ≥4 cycles of chemotherapy had significantly higher 5-year OS and PFS than those who received<4 cycles of chemotherapy (5-year OS:71.3% vs.59.5%,P=0.032;5-year PFS:70.4% vs.54.4%,P=0.009).In addition,multivariate analysis showed that ECOG≥2,primary tumor invasion (PTI),and Ann Arbor stage Ⅱ were associated with poor OS (P=0.006,0.002,0.014),and ECOG≥2 and PTI were associated with reduced LRC (P=0.004,0.016).Furthermore,ECOG≥2,PTI,Ann Arbor stage Ⅱ,and extranasal primary site were associated with lower PFS (P=0.045,0.003,0.030,0.032).Conclusions Extended-field IMRT at a dose of ≥50 Gy can lead to favorable LRC,OS,and PFS in patients with early-stage NKTCL.However,it is less effective against distant early-stage NKTCL in patients with poor prognosis.Nevertheless,≥4 cycles of chemotherapy can significantly improve the OS and PFS of patients with early-stage NKTCL.