Nasopharyngeal Cancer Stage

This clinical trial tests the effect of induction chemotherapy response-guided radiation (de-escalated intensity-modulated radiation therapy \[IMRT\]) compared to standard IMRT in patients with Epstein-Barr virus (EBV)-associated nasopharyngeal cancer. Intensity-modulated radiation therapy (IMRT) is an advanced form of 3-dimensional radiation therapy that uses computer-generated images to show the size and shape of the tumor. Thin beams of radiation of different intensities are aimed at the tumor from many angles. This type of radiation therapy reduces the damage to healthy tissue near the tumor. Radiation therapy sometimes causes unwanted symptoms or side effects, including late effects such as hearing loss and dental problems. The severity of the side effects is related to the radiation dose received and the amount of tissue that received radiation. De-escalation IMRT uses lower doses of radiation based on a good response to induction chemotherapy. Giving de-escalated IMRT may be as effective as standard doses of IMRT in treating patients with EBV-associated nasopharyngeal cancer.