SEER Inquiry System - Question 20160001 Details

Rectal polyp excised in June, 2012, found to have adenocarcinoma in situ in a tubulovillous adenoma. Additional colorectal biopsies in November; all were negative. Another rectal polyp removed in December 2012 showing a tubulovillous adenoma with focal carcinoma in situ. Then, in February, 2013 another rectal polyp removed. This was diagnosed as mod. diff. adenocarcinoma with mucinous features, infiltrating into submucosa, seen in a background of tubulovillous adenoma. Surgical margins free (mucin %=40%). Finally, in May, 2013, a low anterior resection with no residual adenocarcinoma.

This appears to be adenocarcinoma in multiple adenomatous polyps (8221/3), although the final path from May 2013 described one benign polyp and said, 'no other masses, suspicious lesions or polyps are identified.' Going through the MP/H rules, both M13 and M14 result in this being a single primary, and come before the rule about an invasive tumor following an in situ tumor more than 60 days later is a new primary. The original abstract was coded C209 and 8263/2. If this is a single primary, should it be changed to 8221 with a behavior code of 3? Is this scenario another example of when to change the original diagnosis based on subsequent information?