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SEER Inquiry System - Report
Produced: 02/05/2026 4:28 AM
Question 20230029
Inquiry Details
References:
ICD-O-3
Question:
Primary Site--Skin: Are perianal skin primaries within 5 cm of the anus coded as perianal skin (C44.5) or anus (C21.0). See Discussion.
Discussion:
ICD-O-3 tells us that perianal skin is C445 and we do not capture basal or squamous cell skin cancers in our registry. The AJCC manual stages perianal skin cancers within 5 cm of the anus with the anus chapter. We cannot AJCC stage them as an anus if we are not capturing them as C445. I realize we do not code a site in order to stage. We have been following the reportability rules and not capturing. Is this correct? I do not see this addressed in the new Other Sites Solid Tumor Rules.
Answer:
Code primary site based on the site of origin as determined by the physicians. If the physicians state the site of origin is anus, code anus; the same as with skin. As you state, squamous cell cancer of sites coded to C44 is not reportable. The AJCC instruction for physicians to stage perianal neoplasms within 5 cm of the anus using the Anus chapter does not change cancer registry instructions for coding primary site, nor does it affect cancer registry reportability instructions.
