HyperArcTM volumetric modulated arc therapy for hypopharyngeal cancer with solitary recurrence in the cervical vertebra: A case report and literature review.

RATIONALE: It is difficult to reirradiate head and neck cancers because of the toxicity from previous radiation dose delivery. Conventional volumetric modulated arc therapy (VMAT) and intensity-modulated radiation therapy often have poor target coverage. The new HyperArcTM VMAT (HA-VMAT) planning approach reportedly has better target coverage, higher conformity, and can spare normal organs compared to conventional VMAT; however, research on recurrent head and neck cancers is limited. Here, we report the clinical outcomes of HA-VMAT for previously irradiated hypopharyngeal cancer with solitary recurrence in the first cervical vertebra (C1). PATIENT CONCERNS: A 52-year-old Asian male was diagnosed with a hypopharyngeal cancer. The patient received concurrent chemoradiotherapy with a radiation dose of 70 Gy in 33 fractions and achieved complete clinical response. Two years later, solitary recurrence was observed in the C1 vertebra. DIAGNOSES: Solitary recurrence in the C1 vertebra. INTERVENTIONS: Owing to concerns regarding the toxicity to adjacent organs, we decided to use HA-VMAT to achieve better tumor coverage and critical organ sparing. OUTCOMES: Tumor regression was observed on the imaging. At 9 months follow-up, the patient was disease-free and had no late toxicities. LESSONS: This is the first report regarding the clinical outcomes of HA-VMAT for previously irradiated hypopharyngeal cancer with solitary recurrence over the C1 vertebra. HA-VMAT achieves highly conformal dose distribution and excellent sparing of critical organs. There was a favorable initial clinical response with no toxicity. Long-term follow-up is essential in such cases.