The purpose of this study is to determine whether bacterial decolonization of the nares prior to treatment with radiotherapy (RT) for patients with nasopharyngeal carcinoma, can prevent high-grade radiation-induced oral mucositis (RIOM) and improve quality of life.

This study is being conducted because a randomized clinical trials form Yana Kost et al. have found bacterial decolonization in the nose prior to initiation of RT was effective for prevention of acute radiation dermatitis.

Patients in the treatment arm will receive pretreatment with mupirocin ointment to the nares while patients in the control arm will receive standard of care treatment. Bacterial cultures will be taken from the nares and mouth, and participants will also complete a quality of life questionnaire before and after RT.

Inclusion Criteria:

1. Patients with newly histologically confirmed nasopharyngeal carcinoma
2. No evidence of distant metastasis (M0)
3. ECOG (Eastern Cooperative OncologyGroup) scale 0-1
4. 18-70 years old

Exclusion Criteria:

1. Previous or existing mental or cognitive impairment;
2. Patients with other malignant tumors at the same time;
3. Have received bacterial decolonization therapy;
4. Oral mucositis or ulcers existed before radiotherapy.
5. Prior RT to the region of interest