2026 NCCN Guidelines

The 2026 National Comprehensive Cancer Network (NCCN) guidelines for Merkel cell carcinoma (MCC) include important updates from the 2025 guidelines based on the latest research, many of which were led by MC3 Institute members and collaborators. Key changes that are most impactful to patient care include:  

• If the MCC diagnosis was made using a core biopsy, more tumor tissue should attempt to be collected before starting immunotherapy or radiation since extra tissue is needed for blood tests like the circulating tumor DNA [ctDNA] test. 

• Treatment guidelines for an alternative radiation therapy regimen called hypo-fractionated radiation therapy. This approach delivers higher doses of radiation in fewer sessions (e.g. 8Gy in one session, total 8Gy), resulting in a lower total dose overall and a shorter treatment course. Read here about a single-fraction radiation therapy study proposed by the MC3 Institute.

• Recommendations for combination ipilimumab and nivolumab as systemic treatment, particularly for patients who have PD-(L)1 refractory disease. 

These important changes will lead to improved patient outcomes and highlight the importance of the multidisciplinary clinical and translational research being done at the MC3 Institute and many other institutions across the globe. 

Access the 2026 NCCN Guidelines for Merkel cell carcinoma here: Merkel Cell Carcinoma Clinical Resources