Transnasal photoimmunotherapy with cetuximab sarotalocan sodium: Outcomes on the local recurrence of nasopharyngeal squamous cell carcinoma.

Photoimmunotherapy for head and neck cancer (HNC-PIT) is a newly developed locoregional treatment targeting the epidermal growth factor. This treatment consists in administering cetuximab sarotalocan sodium that conjugates cetuximab with the dye IRdye700DX, which is activated by near-infrared ray illumination at 690 nm. HNC-PIT has been conditionally approved in Japan in September 2020 for the treatment of unresectable locally advanced or unresectable locoregionally recurrent HNC. However, its outcomes on the local recurrence of the nasopharyngeal squamous cell carcinoma (NPSCC) remain undetermined. In this report, we assessed the effects of HNC-PIT assisted by transnasal endoscopy on the local recurrence of NPSCC. A 77-year-old male presented with a local recurrence of NPSCC. The initial diagnosis revealed a squamous cell carcinoma, T2N2M0 stage III, positive for Epstein-Barr virus-encoded small RNA by in situ hybridization, which was treated with concurrent chemoradiotherapy (CRT). However, local recurrence was detected 14 months after CRT. We performed HNC-PIT under transnasal endoscopy. Seven months have passed since the HNC-PIT treatment, and the patient is alive without delayed adverse events and evidence of recurrence. Local recurrence of NPSCC, which is difficult to treat with minimally invasive surgery, is considered a potential candidate for HNC-PIT.