Long-term survival after immunotherapy for uncontrolled locally advanced temporal bone squamous cell carcinoma followed by chemoradiotherapy: A case report.

Temporal bone squamous cell carcinoma (TBSCC) is a rare and invasive malignant tumor. The common predisposing factors include a history of local radiotherapy and chronic suppurative otitis media. The current treatment approach for TBSCC primarily involves surgery, followed by adjuvant radiotherapy and chemotherapy, based on T staging and high-risk factors. Although patients with early-stage TBSCC have a high survival rate after treatment, the majority of patients are diagnosed in the intermediate to advanced stages, with extensive tumor involvement, posing challenges for surgical intervention. Definitive chemoradiotherapy (CRT) serves as a viable alternative for unresectable tumors. Constraints in administering curative radiation doses, due to the tolerance of surrounding organs, can lead to uncontrolled tumor growth. Although programmed cell death 1 inhibitors have demonstrated efficacy in head and neck squamous cell carcinoma and cutaneous squamous cell carcinoma, their application in TBSCC remains underexplored. Herein, we report a case of a 47-year-old man diagnosed with unresectable advanced and localized TBSCC. Following inadequate tumor control with primary chemoradiotherapy, immunotherapy was initiated, resulting in disease remission within a follow-up period of > 4 years.