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SEER Inquiry System - Report
Produced: 11/06/2025 4:21 AM
Question 20200013
Inquiry Details
References:
Solid Tumor Rules. Colon, Updated July 2019
Question:
Solid Tumor Rules (2018)/Multiple primaries--Colon: Solid Tumor Rules 2018, Colon Rule M7, bullet 3 indicates that (if neither bullet 1 or 2 apply) a new tumor at the anastomotic site must be stated to arise in the mucosa (confirmed in SINQ 20190096) to qualify as a new primary. However, there is often no clear statement of tumor arising from or involving mucosa (unless the new tumor is limited to the mucosa) noted by pathologists in our region. Do any of the following examples imply a new tumor arising in mucosa per Rule M7, bullet 3? See Discussion.
Discussion:
Examples:
1) New tumor at the ileocolic anastomosis, described as a, Circumferential centrally ulcerated mass with raised borders. Tumor extension: Tumor invades through muscularis propria into subserosal adipose tissue, no involvement of the serosal surface identified. The only mention of mucosa on the resection is the uninvolved enteric mucosa or uninvolved colonic mucosa in the otherwise uninvolved portions of the ileum/colon. If neither bullet 1 or 2 apply, is this a new primary per M7 bullet 3?
2) Right colon with anastomosis site. Tumor site: Anastomosis. Tumor extension: Tumor invades through the muscularis propria. Gross description does not describe mucosa, only noting, at the central area of anastomosis is an ill-defined, slightly raised, tan-brown to purple mass measuring 2.2 x 2 cm, which is nearly circumferential, causing obstruction at the site of anastomosis. If neither bullet 1 or 2 apply, is this a new primary per M7 bullet 3?
3) Polyp at ileocolonic anastomosis, polyp biopsy final diagnosis was, Invasive moderately differentiated colonic adenocarcinoma in association with adenoma. No mention of mucosa on the biopsy final diagnosis or gross description. Clinical info indicates, There is an ulcerated 5 cm mass at the ileo-colonic anastomosis that was biopsied. If neither bullet 1 or 2 apply, is this a new primary per M7 bullet 3?
Answer:
Following the 2018 Colon Solid Tumor Rules M7 and M8:
Example 1: Assuming the first and second tumors are not different histologies or they occurred less than or equal to 24 months apart (M7 Bullets 1 and 2 do not apply), abstract a single primary as the pathology states uninvolved enteric mucosa or uninvolved colonic mucosa (no involvement noted).
Example 2: Assuming the first and second tumors are not different histologies or they occurred less than or equal to 24 months apart (M7 bullets 1 and 2 do not apply), abstract a single primary as there is no mention of mucosal involvement.
Example 3: Assuming the first and second polyps/tumors are not different histologies or they occurred less than or equal to 24 months apart (M7 bullets 1 and 2 do not apply), abstract a single primary as there is no mention of mucosal involvement. Of note in the case of the polyp, tumors coded as adenocarcinoma in a polyp, should be treated as adenocarcinoma (8140) for cases prior to 2018. Also, if the pathologist states the new tumor/polyp originated in the mucosa, it is a new primary.
The rules which address "recurrence or new tumor at the anastomosis were created with the input of several gastrointestinal expert pathologists (CAP, AJCC, and WHO). Pathologists should be following CAP reporting guidelines and include information such as mucosal involvement in the final diagnosis and/or synoptic report. We can revisit this question that all polyps start in the mucosa and if needed, revise the rules to state this.
