Solid Tumor 2026

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Changes needed to the CTC matching algorithm, based on 2026 ST updates

Overall changes across all site groups
In rule statements, update references to column numbers and the site-group instructions
Example: Rule M6 Abstract multiple primaries when separate/non-contiguous tumors are two or more different subtypes/variants in Column 3 Column 2, Table 3 in the Equivalent Terms and Definitions Site-group Instructions.
In the rule: “Abstract a single primary when synchronous, separate/non-contiguous tumors… are on the same row in Table..” Remove column references in Note 2 bullets 2 and 3
Breast
Add 8470 row
Delete Rule M10 (Abstract a single primary when there are multiple tumors of carcinoma NST/duct and lobular). Renumber remaining rules.
Colon
In the 2025 Colon Table, the subtype/variant 8480 appeared twice in the 8140 row. In the 2026 update, they were combined into one entry in the subtype column.
Head and Neck
Table 1: Add subtype variant "HPV-related multiphenotypic sinonasal carcinoma 8483 (/3)” to the 8140 row
Table 1: Delete row: "HPV-related multiphenotypic sinonasal carcinoma 8483 (/3)"
Table 1: Remove subtype/variant Malignant neurilemoma/malignant schwannoma 9560/3 from "Malignant peripheral nerve sheath tumor 9540 (/3)" row
Table 1: Remove all subtypes/variants from "Olfactory neuroblastoma 9522 (/3)" row
Table 1: This may already be correct in the algorithm. 8800 row "Spindle cell rhabdomyosarcoma 8912 (/3)" should be indented under 8900
Table 1: update main term for 8044 to Small cell carcinoma, intermediate
Table 3: Add row "Neuroendocrine carcinoma 8246 (/3)"; see manual for subtypes/variants
Table 3: "Neuroendocrine tumor NOS 8240 (/3)" row: remove "Large cell neuroendocrine carcinoma 8013 (/3)" and "Small cell neuroendocrine carcinoma 8041 (/3)" as subtypes
Table 4: Add Lip primary sites (C000 – C009) ; remove C051 and C052 from Table 4
Table 4: Delete row "Adenosquamous carcinoma 8560"
Table 4: To the "Squamous cell carcinoma 8070 row", add these subtypes: "Adenosquamous carcinoma 8560" and "HPV-associated oral epithelial dysplasia, high grade 8085 (/2)"
Table 5: Add C051 Soft palate and C052 Uvula
This may already be fixed in the algorithm. Table 6: Delete row "Oncocytic carcinoma 8290". It should only appear as a subtype of 8500.
Table 6: "Adenocarcinoma 8140" row: Add subtype "Sclerosing microcystic adenocarcinoma 8407". Delete subtypes "Papillary cystadenocarcinoma 8450" and "Polymorphous adenocarcinoma (PAC)/ Polymorphous low-grade adenocarcinoma /Terminal duct carcinoma 8525" (inadvertently appeared twice in the table-this may be fixed already)
Table 7: "Odontogenic carcinosarcoma 8980" row- histology in col 1 should be changed from 8980 to “9342 (/3)”
Table 8: "Squamous cell carcinoma of the middle ear 8070" row: Add subtype "Squamous cell carcinoma, keratinizing type NOS 8071 (/3)"
Table 10: Delete row "Nasal cavity (excluding nasal cartilage, nasal septum) (C300)"
Kidney
"Neuroendocrine tumor 8240 (/3)" row: Add subtype "Neuroendocrine tumor, grade 2 8249 (/3)"; remove subtypes "Large cell neuroendocrine carcinoma 8013/3" and “Small cell neuroendocrine carcinoma 8041/3" and "Extra-adrenal paraganglioma 8693/3"
Add row "Neuroendocrine carcinoma 8246 (/3)"
paraganglioma 9700/3 row: Change code from 9700/3 to 8693/3
Lung
8250/2 and 8250/3 combined into one entry
Melanoma
Remove histology codes from all histologies except Spindle cell melanoma 8772 (/3)
Non-malignant CNS
Rule M8: change site code for bullet “Meninges of cranial nerves site code” to "C700"
Other Sites
Table 2: "Liposarcoma NOS 8850" row: change "Mixed liposarcoma 8855" to "Liposarcoma NOS 8850"
Table 2: Delete row "Teratocarcinoma 9081"
Table 3: Add rows: "Mixed neuroendocrine–non-neuroendocrine neoplasm 8154 (/3)"; and "Mixed neuroendocrine–non-neuroendocrine neoplasm 8154 (/3)". See manual for subtypes.
Table 3: "Neuroendocrine tumor 8240 (/3)" row: Remove subtypes "Large cell neuroendocrine carcinoma 8013 (/3)" and "Small cell neuroendocrine carcinoma 8041 (/3)"; Add subtype "Neuroendocrine tumor, grade 2 8249 (/3)"
Table 5: Add row "Neuroendocrine carcinoma 8246 (/3)"; see manual for subtypes.
Table 5: "Neuroendocrine tumor 8240 (/3)" row: Remove subtypes "Neuroendocrine carcinoma 8246/3" and "Large cell neuroendocrine carcinoma 8013 (/3)" and "Small cell neuroendocrine carcinoma 8041 (/3)"; Add subtype "Neuroendocrine tumor, grade 2 8249 (/3)"
Table 14: Add C481 and C488
Table 16: Add rows "Mixed neuroendocrine non-neuroendocrine carcinoma 8154 (/3)" and "Neuroendocrine tumor NOS 8240 (/3)"
Table 16: "Neuroendocrine carcinoma NOS 8246 (/3)" row: remove subtype "Mixed neuroendocrine non-neuroendocrine carcinoma (MiNEN) 8154"
Table 17: Add row: "Mixed neuroendocrine non-neuroendocrine carcinoma 8154 (/3)"
Table 17: 8246 row: remove subtype 8154
Table 19: Remove row "Adenoid cystic carcinoma 8200"