Application of modified shrinking field radiation in RT-DeVIC chemoradiotherapy for treating localized extranodal natural killer/T-cell lymphoma

[ABSTRACT] Concurrent chemoradiotherapy (CRT) is the recommended treatment for localized extranodal natural killer/T-cell lymphoma, nasal type (ENKL). In 2009, the Japan Clinical Oncology Group first documented the safety and efficacy of a regimen involving radiotherapy (RT) plus dexamethasone, etoposide, ifosfamide, and carboplatin (DeVIC) in their phase I/II trials (JCOG0211 study). The application of this regimen has drastically improved outcomes of patients with localized ENKL. In 2013, the current guidelines were made to the cost in JCOG0211 study. We retrospectively investigated the outcomes of three patients who received CRT for stage localized ENKL at the Kawasaki Medical School Hospital between August 2007 and March 2011. Our CRT protocol differed from that used in the JCOG0211 study as we used a different shrinking field RT method. A recent report on shrinking or extended-field RT raised questions regarding which fields are appropriate. Thus, we compared our clinical results with those of the JCOG0211 study and analyzed the effect of the differences in field size on clinical results. The median follow-up of the three patients in the present study was 9 months (range, 5-106 months), two and one of whom achieved complete and partial responses, respectively. Regarding adverse events, no severe acute side effects (e.g., mucositis) higher than Grade 4 were observed. We reviewed cases and the JCOG0211 study which we experienced in the past about fields of the RT. The present study described our experiences with three patients receiving shrinking field RT.