Definitive radiotherapy for a head and neck Merkel cell carcinoma and comprehensive nodal volumes: a case for using a computer-designed variable-thickness compensator to reduce risk and severity of mucositis.

When contemplating how to treat head and neck primary cancers and regional lymph nodes with radiotherapy, we often select the contemporary intensity-modulated radiotherapy (IMRT) without much consideration of older methods that may give fewer side effects and be more cost-effective. For an 87-year-old female with a 1.5-cm Merkel cell carcinoma (MCC) located 1.5 cm lateral to the orbital rim, we were challenged to deliver 50 Gy to comprehensive elective nodal regions and 70 Gy to the primary. We were particularly concerned about the potential adverse acute effects of radiotherapy to mucosal structures in this elderly female. Acute mucositis could impair nutrition, quality of life, and treatment intensity especially given her age. We compared 3 techniques that are appropriate for this target: step-and-shoot IMRT, matched electron fields (MEF), and electron conformal therapy (BolusECT™). We selected and treated her with BolusECT™ because of better sparing of larynx, pharynx, oral cavity and lips, and shortest treatment time. This is a reasonable option for treating ipsilateral head and neck target volumes at centers where only these 3 techniques are available.