#1: Solid Tumor Rules (2018)
#2: Multiple primaries
#3: Head & Neck
Source 1: 2018 Solid Tumor Rules
Notes: Head and Neck, January 2019 update
Source 2: WHO Class H & N Tumors
Solid Tumor Rules (2018)/Multiple Primaries--Head & Neck: How many primaries are accessioned when a patient is diagnosed with right nasal cavity (C300) invasive nonkeratinizing squamous cell carcinoma (8072/3) in 2015 treated with radiation and excision, followed by a 2019 right nasal cavity (C300) invasive squamous cell carcinoma (NOS, 8070/3)? See Discussion.
Head and Neck Multiple Primary Rule M8 appears to be the first rule that applies to this case and instructs the user to abstract multiple primaries when separate/non-contiguous tumors are on different rows in the appropriate site table (Tables 1-9) in the Equivalent Terms and Definitions. Table 1 (tumors of the nasal cavity) shows Non-keratinizing squamous cell carcinoma and squamous cell carcinoma on different rows making the 2019 case a new primary. Is this correct?
Abstract two primaries using Head and Neck Solid Tumor Rule M8 when separate/non-contiguous tumors are on different rows in the appropriate site table, in this case, Table 1 Nasal Cavity and Paranasal Sinuses.