Locally advanced and metastatic Cutaneous Squamous Cell Carcinoma (cSCC)

Authored by Open Medicine, published on 2026-08-03 19:17:53.0

The algorithm is broadly aligned with contemporary management of locally advanced/metastatic cSCC, particularly the prioritization of PD-1 blockade for unresectable or metastatic disease and use of surgery and adjuvant RT for appropriate resectable high-risk cases. Inclusion of neoadjuvant PD-1 for borderline resectable disease reflects an evidence-supported but still evolving area. The adjuvant systemic immunotherapy component is appropriately flagged as emerging, with practice variation depending on guideline updates, approvals, and trial maturation.

  1. Confirmed locally advanced or metastatic cutaneous squamous cell carcinoma
    Confirm cutaneous origin, extent of disease, treatment intent, and eligibility for surgery, radiotherapy, or systemic therapy.
    • MDT Review
      Confirm cutaneous origin, extent of disease, resectability, radiation feasibility, immune risk, transplant/immunosuppression status, and treatment intent through MDT review. MDT review should include dermatology, surgical oncology or Mohs surgery, head and neck surgery when relevant, radiation oncology, medical oncology, pathology, radiology, and transplant/immunology teams when relevant.
      • Special population: transplant, immunosuppression, or active autoimmune disease
        Use individualized risk–benefit assessment with oncology and the relevant transplant or organ specialist. Checkpoint inhibition may increase the risk of allograft rejection or autoimmune-disease exacerbation. Consider alternative local or systemic strategies and clinical-trial participation when appropriate. Selected kidney-transplant recipients have received cemiplimab with protocolized modification of immunosuppression, but these limited data should not be generalized to all transplant types or immunosuppressive regimens. Consider Clinical Trials for immunosuppressed patients: Study of Intralesional Cemiplimab in Adult Patients With Early Stage Cutaneous Squamous Cell Carcinoma A Randomized Phase II Study of Amivantamab (JNJ-61186372) and Hyaluronidase (rHuPH20) Versus Cetuximab in Immunocompromised Participants With Recurrent Inoperable or Metastatic Cutaneous Squamous Cell Carcinoma
        • Patient specific MDT pathway
      • Resectability and Curative Local-Therapy Assessment
        Is the disease clearly resectable, borderline resectable with potentially morbid surgery, or unresectable / not amenable to curative local therapy?
        • Borderline Resectable / Function-Threatening Surgery
          For disease that is technically resectable but would require morbid, disfiguring, function-threatening, or organ-threatening surgery, discuss neoadjuvant immunotherapy in MDT. Best fit: - Resectable stage II–IV disease where surgery is feasible but high morbidity is expected. - Head and neck cSCC where surgery may compromise function, cosmesis, eye/ear/nose structures, facial nerve, swallowing, or quality of life. - Patient is fit for immunotherapy and can be monitored closely. - No urgent need for immediate definitive local control. Important caveat: Neoadjuvant immunotherapy may downstage disease and improve surgical feasibility, but omission of surgery should not be presented as routine standard care outside clinical trial or expert MDT context.
          • MDT-selected neoadjuvant cemiplimab approach
            Consider neoadjuvant cemiplimab in selected patients with resectable cSCC when standard surgery would cause major functional, cosmetic, or organ morbidity. Plan definitive surgery before treatment and reassess resectability after the neoadjuvant course. Routine omission of surgery after response is not established and should be considered only in a clinical trial or an exceptional expert-MDT setting.
            • Reassess after neoadjuvant cemiplimab
              Reassess clinical and radiographic response, resectability, anticipated surgical morbidity, and the feasibility of definitive local treatment through MDT review.
              • Resectable / Definitive Surgery Appropriate
                • Surgery
                  • Postoperative high-risk features and adjuvant eligibility?
                    • Yes -- High-Risk Disease Eligible after Surgery and RT
                      • Postoperative RT → adjuvant cemiplimab for FDA-defined high-risk disease
                        For adults with cSCC at high risk of recurrence after surgery and radiation, adjuvant cemiplimab is FDA-approved. Confirm completion of postoperative radiation, current regional labeling, treatment eligibility, immune-risk profile, toxicity considerations, access, and shared decision-making.
                        • Ongoing response and toxicity monitoring
                    • No Current Adjuvant Indication
                      • Ongoing response and toxicity monitoring
              • Not Resectable / No Curative Local Option
                • Transition to unresectable / systemic-therapy pathway
                  If the disease is no longer amenable to curative surgery or radiotherapy after neoadjuvant treatment, proceed to the unresectable/systemic-therapy pathway for approved checkpoint inhibitor therapy and subsequent management.
                  • Approved checkpoint inhibitor options
                    FDA-approved checkpoint inhibitor options for adults with locally advanced or metastatic cSCC who are not candidates for curative surgery or curative radiation: Approved anti–PD-1 options: • Cemiplimab-rwlc. • Pembrolizumab. Approved anti–PD-L1 option: • Cosibelimab-ipdl. Select treatment according to the labeled indication, immune-risk profile, toxicity considerations, access, and patient preference.
                    • Initiate checkpoint inhibitor therapy + safety monitoring
                      Baseline assessment and ongoing monitoring/management of immune-related adverse events (including pneumonitis, colitis, hepatitis, endocrinopathies, nephritis, myocarditis, neurologic toxicities) are supported by major society guidance for checkpoint inhibitors and are applicable across PD-1/PD-L1 agents.
                      • Assess response, clinical benefit, and treatment tolerance
                        Is there meaningful clinical benefit with acceptable toxicity, or confirmed progression / unacceptable toxicity? Assess: Clinical response and symptom improvement. Radiographic response according to disease extent and treatment plan. Functional outcome and quality of life. Treatment tolerance and immune-related toxicity. Whether stable disease represents meaningful ongoing clinical benefit. Whether apparent early progression could represent pseudoprogression in an otherwise clinically stable patient. Whether local therapy could address symptomatic, threatening, or oligoprogressive disease. Do not change treatment automatically for an isolated early imaging change without reviewing symptoms, disease tempo, confirmatory imaging when appropriate, and MDT context.
                        • Clinical Benefit + Acceptable Toxicity
                          • Continue checkpoint inhibitor ± local RT when appropriate
                            Continuation of PD-1 therapy in responders aligns with how pivotal PD-1 trials administered treatment until progression/toxicity and with guideline-based principles for ongoing systemic therapy. Adding RT for consolidation/symptom control is supported mainly by guideline practice patterns and extrapolation rather than definitive randomized evidence specific to this exact sequencing in cSCC.
                            • Ongoing response and toxicity monitoring
                        • Confirmed Progression or Unacceptable Toxicity
                          • MDT reassessment and next-line strategy
                            Reassess disease distribution, prior checkpoint inhibitor exposure, treatment tolerance, performance status, local-treatment opportunities, clinical-trial eligibility, access, and goals of care.
                            • Open: Later-line / palliative management pathway
                              Select clinical trial, EGFR-directed therapy, chemotherapy, palliative local therapy, or supportive care according to prior checkpoint inhibitor exposure, disease distribution, performance status, toxicity, access, and goals of care.
        • Unresectable / Not a Candidate for Curative RT
          • Approved checkpoint inhibitor options
            FDA-approved checkpoint inhibitor options for adults with locally advanced or metastatic cSCC who are not candidates for curative surgery or curative radiation: Approved anti–PD-1 options: • Cemiplimab-rwlc. • Pembrolizumab. Approved anti–PD-L1 option: • Cosibelimab-ipdl. Select treatment according to the labeled indication, immune-risk profile, toxicity considerations, access, and patient preference.
            • Initiate checkpoint inhibitor therapy + safety monitoring
              Baseline assessment and ongoing monitoring/management of immune-related adverse events (including pneumonitis, colitis, hepatitis, endocrinopathies, nephritis, myocarditis, neurologic toxicities) are supported by major society guidance for checkpoint inhibitors and are applicable across PD-1/PD-L1 agents.
              • Assess response, clinical benefit, and treatment tolerance
                Is there meaningful clinical benefit with acceptable toxicity, or confirmed progression / unacceptable toxicity? Assess: Clinical response and symptom improvement. Radiographic response according to disease extent and treatment plan. Functional outcome and quality of life. Treatment tolerance and immune-related toxicity. Whether stable disease represents meaningful ongoing clinical benefit. Whether apparent early progression could represent pseudoprogression in an otherwise clinically stable patient. Whether local therapy could address symptomatic, threatening, or oligoprogressive disease. Do not change treatment automatically for an isolated early imaging change without reviewing symptoms, disease tempo, confirmatory imaging when appropriate, and MDT context.
                • Clinical Benefit + Acceptable Toxicity
                  • Continue checkpoint inhibitor ± local RT when appropriate
                    Continuation of PD-1 therapy in responders aligns with how pivotal PD-1 trials administered treatment until progression/toxicity and with guideline-based principles for ongoing systemic therapy. Adding RT for consolidation/symptom control is supported mainly by guideline practice patterns and extrapolation rather than definitive randomized evidence specific to this exact sequencing in cSCC.
                    • Ongoing response and toxicity monitoring
                • Confirmed Progression or Unacceptable Toxicity
                  • MDT reassessment and next-line strategy
                    Reassess disease distribution, prior checkpoint inhibitor exposure, treatment tolerance, performance status, local-treatment opportunities, clinical-trial eligibility, access, and goals of care.
                    • Open: Later-line / palliative management pathway
                      Select clinical trial, EGFR-directed therapy, chemotherapy, palliative local therapy, or supportive care according to prior checkpoint inhibitor exposure, disease distribution, performance status, toxicity, access, and goals of care.
        • Clearly Resectable
          • Surgery
            • Postoperative high-risk features and adjuvant eligibility?
              • Yes -- High-Risk Disease Eligible after Surgery and RT
                • Postoperative RT → adjuvant cemiplimab for FDA-defined high-risk disease
                  For adults with cSCC at high risk of recurrence after surgery and radiation, adjuvant cemiplimab is FDA-approved. Confirm completion of postoperative radiation, current regional labeling, treatment eligibility, immune-risk profile, toxicity considerations, access, and shared decision-making.
                  • Ongoing response and toxicity monitoring
              • No Current Adjuvant Indication
                • Ongoing response and toxicity monitoring
  2. Selective biomarkers / NGS / ctDNA — expert note
    Selective biomarkers / NGS / ctDNA Routine NGS, PD-L1 testing, or ctDNA assessment is not required before checkpoint inhibitor therapy. Consider selectively for unusual biology, refractory disease, tissue limitation, or clinical-trial matching. Testing should not delay treatment.
tosprivacyEfficacy and safety of cosibelimab 800 mg every 2 weeks for locally advanced cutaneous squamous cell carcinoma: Updated follow-up from a pivotal studyPD-1 blockade with cemiplimab in advanced cutaneous squamous-cell carcinoma (EMPOWER-CSCC-1)Pembrolizumab for locally advanced and recurrent/metastatic cutaneous squamous cell carcinoma (KEYNOTE-629 study)FDA approves cosibelimab-ipdl for metastatic or locally advanced cutaneous squamous cell carcinoma.Stratigos AJ, Dessinioti C, Garbe C, Lebbe C, Amaral T, Bataille V, et al. European consensus-based interdisciplinary guideline for invasive cutaneous squamous cell carcinoma. Part 1: Diagnostics and prevention – Update 2026. Eur J Cancer. 2026.Stratigos AJ, Dessinioti C, Garbe C, Lebbe C, Amaral T, Bataille V, et al. European consensus-based interdisciplinary guideline for invasive cutaneous squamous cell carcinoma. Part 2: Treatment – Update 2026. Eur J Cancer. 2026.Gross ND, Miller DM, Khushalani NI, Divi V, Ruiz ES, Lipson EJ, et al. Neoadjuvant cemiplimab for stage II to IV cutaneous squamous-cell carcinoma. N Engl J Med. 2022;387(17):1557-1568.Gross ND, Miller DM, Khushalani NI, Divi V, Ruiz ES, Lipson EJ, et al. Neoadjuvant cemiplimab and surgery for stage II–IV cutaneous squamous-cell carcinoma: follow-up and survival outcomes. Lancet Oncol. 2023;24(11):1196-1205.Neoadjuvant-Intent Immunotherapy in Advanced, Resectable Cutaneous Squamous Cell CarcinomaRANDOMIZED PHASE III TRIAL OF NEOADJUVANT IMMUNOTHERAPY WITH RESPONSE-ADAPTED TREATMENT VERSUS STANDARD-OF-CARE TREATMENT FOR RESECTABLE STAGE III/IV CUTANEOUS SQUAMOUS CELL CARCINOMAManagement of toxicities from immunotherapy: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up.Management of immune-related adverse events in patients treated with immune checkpoint inhibitor therapy: ASCO Guideline Update. J Clin Oncol.Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immune checkpoint inhibitor-related adverse eventsThe Mutational and Microenvironmental Landscape of Cutaneous Squamous Cell Carcinoma: A ReviewPlasma circulating tumor DNA in patients with cutaneous squamous cell carcinoma: Initial experience.Incidence and Impact of ctDNA Positivity in Cutaneous Squamous Cell CarcinomaCemiplimab for Kidney Transplant Recipients With Advanced Cutaneous Squamous Cell Carcinoma