Chemoradiotherapy for localized extranodal natural killer/T-cell lymphoma, nasal type, using a shrinking-field radiation strategy: multi-institutional experience.

PURPOSES: The prognosis of localized extranodal natural killer/T-cell lymphoma, nasal type (ENKTL), has improved with the development of chemoradiotherapy. However, conventional extended-field radiotherapy may cause optic disorders. Our group has employed smaller radiation fields in an attempt to avoid toxicity. The efficacy and toxicity of treatments were evaluated. MATERIALS AND METHODS: Chemoradiotherapy was delivered with a shrinking-field radiotherapy strategy. The endpoints of this study were overall survival (OS), local control (LC), progression-free survival (PFS), and toxicity. RESULTS: Fifteen patients with localized ENKTL were treated. After irradiation (median, 40 Gy) to the tumor plus a prophylactic volume, a reduced treatment volume to the tumor was boosted (median, 10 Gy). Twelve patients underwent chemoradiotherapy and 3 patients received radiotherapy alone. A complete response was achieved in 12 and a partial response in 3 patients. The 5-year OS, PFS, and LC rates were 80, 67, and 93 %, respectively. Distant recurrence occurred in 4 patients and locoregional and distant recurrence in 1 patient. Cataract (grade 3) and dry eye (grade 2) were observed as late adverse events in 1 patient each. CONCLUSIONS: Sufficiently high OS and LC were achieved with acceptable toxicities. Appropriate target volumes may be smaller with newer chemotherapy regimens.