What the Standard Pathology Lab Can Provide in Terms of Markers: Not All Stage II Colon Cancers Are Equal

摘要

Standard gross and histologic examination of the resection specimen for a colon cancer can demonstrate ways in which stage II colon cancers are different from each other, many of which are associated with differences in recurrence risk and/or prognosis. The first is the depth of invasion, or the pathologic T descriptor. Stage II tumors may invade through the muscularis propria but not reach the serosa (pT3, stage IIa), they may invade the serosa (pT4a, stage IIb), or they may invade adjacent organs (pT4b, stage IIc). pT4 has been reported to be a bad prognostic factor. It should be noted, however, that T4a (invasion of the serosa), may be difficult to recognize histologically and/or be associated with inter-observer variability. This may be due to undersampling or failure to recognize that serosal involvement may manifest itself by other findings besides tumor cells directly on the serosa, such as an inflammatory reaction or mesothelial hyperplasia. Also, what looks like T4b at the gross level may be due to inflammatory adhesions rather than tumor extension. It should also be noted that a clinical presentation of obstruction or perforation is also a bad prognostic feature.