sessile polyp

Invasion in sessile polyp

Haggitt defined the submucosal invasion in all sessile polyps as level 4 and therefore associated with bad outcome, independently of the affection or not of the resection margins.

Despite Haggitt’s classification has been widely used to evaluate the resection quality of endoscopic polypectomies, this is less useful in non-pedunculated, flat or depressed lesions.

The most accepted classification for them is Kikuchi’s one, quantifying the grade of vertical and horizontal submucosal invasion: submucosa is divided into superior third (Sm1), medium third (Sm2) and lower third (Sm3).

Superior third is subdivided into 3 subtypes depending on horizontal spread in relation with the tumoral size.

Referring to the outcome, Sm1 is equivalent to Haggitt’s level 1, Sm 2 to levels 2 and 3, and Sm3 may correspond with a level 4. Sm1a or Sm1b lesions without invasion never develop metastases.

Lesions with deeper or more extent affection are able to develop metastases, determining the necessity of aggregating a surgical treatment after finishing the endoscopic one.

Open references

 Endoscopic resection as unique treatment for early colorectal cancer. Revista Española de Enfermedades Digestivas. Rev. esp. enferm. dig. v.102 n.7 Madrid jul. 2010. http://dx.doi.org/10.4321/S1130-01082010000700006