Comparing Radical Surgery and Radical Radiotherapy as First Definitive Treatment for Primary MCC

Inclusion Criteria: General Inclusion Criteria for All Patients: 1. Patients newly diagnosed with histologically-proven MCC (either primary and/or regional nodal disease) 2. Completion of clinical and radiological staging investigations, including CT imaging (or other modality) of regional nodal basin(s) and major viscera (and SLNB if clinically appropriate) to identify regional and distant metastases 3. No confirmed distant metastases beyond the regional nodal basin (i.e. not stage IV disease) 4. Suitable for radical treatment to achieve disease control 5. Able to give valid informed consent 6. Consent for collection of data and tissue samples and follow up 7. Life expectancy six months or greater in relation to general fitness and co-morbidities Additional Inclusion Criteria for Rational Compare: 1. Patients newly diagnosed with histologically-proven primary MCC 2. In the opinion of the SSMDT, the primary MCC can be encompassed both within a wide surgical margin and within a radiotherapy field, and the SSMDT is in equipoise regarding WLE or radiotherapy as first treatment 3. A minimum margin of 1 cm surrounding the MCC achievable by either radiotherapy or surgery 4. Consent for randomisation into Rational Compare Exclusion Criteria: 1. The primary MCC has already been treated radically with WLE (surgical margins \>10 mm) or radiotherapy 2. Intended use of regional or systemic chemotherapy for MCC (including molecularly targeted agents and immunotherapy)