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pT1 invasive colorectal adenocarcinoma

Friday 15 February 2013

pT1 colorectal adenocarcinoma; pT1 colon adenocarcinoma

In the colorectum, submucosal invasion is required for the diagnosis of a pT1 tumor.

Nota bene: It should be noted that when a diagnosis of pT1 invasive carcinoma is rendered, it means that carcinoma has at least invaded into the submucosa of the colorectum. This differs from the concept of invasion in other parts of the gastrointestinal tract (esophagus, stomach and small intestine), where the presence of mucosal invasion is sufficient for the diagnosis of invasive carcinoma (pT1).

Intramucosal vesus in situ WHO Tis

In the colorectum, submucosal invasion is required for the diagnosis of a pT1 tumor.

For reasons that are not entirely clear but generally thought to be due to the relative paucity of lymphatics, invasion confined to the lamina propria and muscularis mucosae has no risk of nodal or distant metastasis.

Thus, intramucosal carcinoma is preferably called "high grade dysplasia" (discussed later) by pathologists in order to avoid unnecessary surgical intervention.

In the American Joint Committee on Cancer (AJCC) Cancer Staging Manual, mucosal invasion is classified as carcinoma in situ (Tis).

Nevertheless, the term of "intramucosal carcinoma" may still be used by some pathologists.

No matter what term is used by pathologists, the identification of "high grade dysplasia" or "intramucosal carcinoma" in a biopsy or polypectomy specimen should not affect the decision-making for patient management.

The decision to perform surgical resection should be ultimately determined by the gross appearance of the lesion, endoscopic ultrasound findings, and endoscopic resectability.