The emerging role of radiotherapy for desmoplastic melanoma and implications for future research.

The National Comprehensive Cancer Network (NCCN) 2014 guidelines are unclear about the role of radiotherapy in the management of desmoplastic melanoma. The guidelines specify that radiotherapy can be 'considered' for select patients with desmoplastic melanoma with narrow surgical margins. Patient selection criteria, including margins, are not well defined, causing considerable differences in practice patterns across the country. There are also several conflicting reports about the role of radiotherapy in improving postsurgical outcomes when other adverse pathological risks factors, such as increased Clark level, head and neck involvement, perineural invasion, positive margins, or recurrent disease, are also present. Recent data provide further clarification and insights into the role of radiotherapy. Thus, in light of the NCCN guidelines and the recently published series, we critically review the role of radiotherapy for desmoplastic melanoma. In our review, we highlight the published risk factors that predict for increased risk of recurrence after surgery. We also provide a comparison of surgical and radiation outcomes data, and then address areas for further research.