Pseudoprogression in the era of immunotherapy-based strategies for recurrent head and neck squamous cell carcinoma achieving complete response: A case report

Rationale:In the last few years, treatment of head and neck squamous cell carcinoma (HNSCC) has been enhanced by the emergence of immunotherapy. A biological phenomenon unique to immunotherapy is pseudoprogression, an increase in tumor burden or the appearance of a new lesion subsequently followed by tumor regression. Patient concerns:A 78-year-old man complaining of a lump (6*4 cm) gradually swelling on the right side of his neck with recurrent buccal mucosa squamous cell carcinoma presented to our institution. Two months prior, he received resection of the buccal lesion but refused suggested adjuvant chemoradiotherapy after the operation. Diagnoses:Recurrent buccal mucosa squamous cell carcinoma. Interventions:Induction immunotherapy was initiated, followed by a new node appearing on the surface of the neck mass. We considered the presence of pseudoprogression and continued with immunotherapy. The patient received immunotherapy combined with chemotherapy and intensity-modulated radiation therapy (IMRT) consecutively. Outcomes:The patient experienced an excellent recovery with the disappearance of pain and the lump, along with return of a healthy appetite, weight gain and positive outlook. Complete response (CR) was also noted by magnetic resonance imaging (MRI) scan, with the upper right neck mass significantly retreated to unclear display. The patient is still alive with stable, asymptomatic disease at the time of this writing. Lessons:These results provide confidence in the safety and efficacy of radical chemo-radio-immunotherapy for the treatment of recurrent, unresectable or metastatic HNSCC.