The impact of introducing cemiplimab as adjuvant treatment in high-risk cutaneous squamous cell carcinoma on NHS services and facilities.

Abstract

e18031 Background: The recently published C-POST phase 3 trial has shown improved disease-free survival and reduced locoregional recurrence with adjuvant cemiplimab in high-risk locally advanced cutaneous squamous cell carcinoma (CSCC). Incorporating adjuvant cemiplimab into current standard-of-care regimes will represent a significant shift in practice. Our aim was to assess the impact of this change by calculating the number of potentially eligible patients treated in a busy tertiary head and neck cancer (HNC) centre and estimating the effect on resources for future service planning. Methods: With institutional approval (The Clatterbridge Cancer Centre NHS Foundation Trust), we identified HNC patients with cutaneous squamous cell carcinoma referred for radiotherapy after ablative surgery between October 1, 2024, and September 30, 2025. All radiotherapy referrals were captured. A retrospective case-note review identified patients meeting nodal and non-nodal high-risk criteria from the C-POST trial. Additional variables included age, gender, primary diagnosis, ethnicity, demographics, TNM staging, histology, radiotherapy site and dose, and reasons for not receiving radiotherapy. Results: 164 patients were referred, of whom 84.14% (138) were referred for adjuvant radiotherapy, 6.7% (11) for radical radiotherapy, 6.1% (10) for palliative radiotherapy, and 3.04% (5) were inappropriate referrals. Mean age was 80.5 years (SD 9.68) and M:F was 4:1. Overall, 90.85% (149) were eligible for adjuvant or radical radiotherapy. Among eligible patients, 65.8% (n=98) received radiotherapy, 20.1% (n=30) opted for surveillance, 8.7% (n=13) for surgical excision, 2.7% (n=4) declined treatment, and 2.7% (n=4) were unsuitable due to poor PS. In total, 54.87% (n=90) had high-risk nodal or non-nodal disease and were eligible for adjuvant cemiplimab. Within this group, 74.2% (n=66) had perineural invasion, 15.7% (n=14) recurrent CSCC with ≥N2b, ≥T3 or poorly differentiated histology, 5.7% (n=6) nodal disease with ECE, 2.2% (n=2) T4 lesions, and 1.1% (n=1) in-transit metastases. Based on C-POST, the cohort requires ~2849 hospital visits for adjuvant cemiplimab. Each patient needs an initial radiological assessment, 10 pretreatment assessment/blood visits, 10 treatment visits, 4 visits for surveillance scans, and 6 visits for consultant review. Immune-related toxicity management adds ~59 visits, assuming 20% experience one toxicity episode requiring ≥3 attendances plus ~5 additional visits for imaging or blood tests. Conclusions: Introducing adjuvant cemiplimab in high-risk cutaneous squamous cell carcinoma at a busy NHS tertiary cancer centre is feasible but will lead to major changes in treatment protocols and service provision. This audit provides a benchmark to aid service development and quantify the need for future departmental expansion.