Cutaneous squamous-cell carcinoma of the head-neck area refractory to chemo-radiotherapy: benefit from anti-PD-1 immunotherapy.

Objective: Radiotherapy provides excellent results in locally advanced cutaneous squamous-cell carcinoma of the head and neck area (cSCC-HN), with a 2-year local progression-free interval obtained for about 80% of patients. Overexpression of immune checkpoint co-inhibitory molecules, like PD-L1 (programmed death ligand 1), by cancer cells may define local immunosuppression, tumour escape from immune surveillance and reduced radiotherapy efficacy.

Methods: A 65-year-old female, with a large exophytic cSCC-HN invading adjacent soft tissues, was treated with hypofractionated accelerated chemo-radiotherapy. The patient received four bi-weekly cycles of chemotherapy concurrently with eight fractions of 5.5 Gy (two fractions per week). Two months after the end of chemo-radiotherapy, the tumour was stable in dimensions, without any signs of symptomatic relief. The patient was, after that, treated with anti-PD-1 immunotherapy (nivolumab). The tumour gradually regressed, reaching partial response after four cycles and complete response after 16 cycles of nivolumab. No side-effects related to immunotherapy were recorded. The patient is alive and without evidence of disease 28 months after radiotherapy.

Conclusions: Treatment of patients with chemo- and radio-resistant cSCC-HN with immunotherapy may optimize the efficacy of radiotherapy by stimulating immunological tumour rejection mechanisms. cSCC-HN patients who fail to respond to chemo-radiotherapy completely are expected to benefit the most from immunotherapy because of the radio-vaccination effect expected from the preceded radiotherapy.