Comparisons of skin toxicity in patients with extranodal nasal-type natural killer/T-cell lymphoma after treatment with intensity-modulated radiotherapy and conventional radiotherapy

Background: Intensity-modulated radiation therapy (IMRT) has been more widely used in extranodal nasal-type natural killer/T-cell lymphoma (NKTCL) because it can maximally improve the local control rate of tumor and reduce the radiation dose received by surrounding normal tissues. However, there has been no consensus on whether IMRT can help to lower the toxic and adverse reactions caused by radiation therapy. The aim of this study is to compare skin toxicity caused by IMRT and conventional radiotherapy in Stage I-II NKTCL. Methods: A total of 93 patients with Stage I-II NKTCL, nasal-type arising in the nasal cavity were consecutively treated using curative radiotherapy between April 2005 and August 2014. These patients received radiotherapy without chemotherapy. Definitive radiotherapy was conducted using conventional radiotherapy in 33 patients and IMRT in the other sixty patients with a regional field and a total dose of 50 Gy. Dosimetric parameters of radiation treatment plans and skin toxicity were analyzed and compared between conventional radiotherapy and IMRT. Results: From the dosimetric analysis, IMRT demonstrated significantly improved dose coverage and homogeneity than conventional radiotherapy. Meanwhile, the Grade 1, 2, and 3 skin toxicity incidences in conventional radiotherapy group were 42.4%, 39.4%, and 18.2%, and in IMRT group were 25.0%, 31.7%, and 43.3%, respectively. Our data suggested that the severity of skin toxicity in IMRT group was statistically higher than that in conventional radiotherapy group. Conclusions: IMRT provided improved dose coverage than conventional radiotherapy. However, IMRT failed to lower patients' risks for skin toxicity and may have the potential to increase skin toxicity.