Radiation-induced nausea and vomiting in head and neck cancer: Is it something worth considering in the intensity modulated radiotherapy era? "A narrative review"

Radiation therapy is one of the cornerstones in the treatment of head and neck squamous cell carcinomas (HNSCC), alone or in combination with chemotherapy or surgery. Technological advances which occurred over the last few decades have increased the efficacy of radiotherapy (RT), particularly, intensity-modulated RT (IMRT). IMRT can deliver treatments on complex tumoral targets with dose escalation while sparing organs at risk; anyway IMRT deposits dose in unpredictable patterns outside of the target volume with the purpose of improving conformality. Radiation-induced nausea and vomiting (RINV) is a frequent albeit neglected side effect of RT that can lead to delays in treatment with serious consequences on cure rates. According to several guidelines (MASCC 2016, NCCN 2018), RT for HNSCC has traditionally been regarded as a low emetic risk treatment. Nevertheless, several works suggest that IMRT could increase RINV. Further studies are needed to define the exact incidence and the detailed pathophysiology of RINV in patients with HNSCC treated with state of art IMRT techniques, with and without concurrent chemotherapy.