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SEER Inquiry System - Report
Produced: 03/09/2026 8:10 AM
Question 20210006
Inquiry Details
References:
#1: 2018 Summary Stage, 147. September 2020
#2: AJCC Cancer Staging Manual. 8th edition
Question:
Behavior/Summary Stage 2018--Colon: What is the correct behavior and Summary Stage for a case of intramucosal adenocarcinoma arising in tubular adenoma? AJCC states this is Tis, though SEER Summary Stagie states this is Localized (code 1). The histology is 8140/2 (adenocarcinoma in situ), but the SEER Summary Stage is Locallized.
Discussion:
Answer:
Intramucosal carcinoma of the colon is assigned behavior code of /3. Intramucosal is not the same as in situ in terms of behavior. Behavior and staging are separate concepts, although there is some overlap. Use the instructions for coding behavior to code this field. Do not use stage to determine behavior in this case.
For purposes of Summary Stage, intramucosal carcinoma is a localized lesion; however, for purposes of AJCC staging, assign Tis for the stage.
