Objective: a) to evaluate the appropriateness of histological criteria as proposed by Morson as indicators for surgery; and b) to compare the adequacy of Morson s criteria with Haggitt s levels as indicators for surgery in the case of malignant sessile lesions.
Material and methods: we carried out a prospective, protocolized study of 42 patients with polyps with invasive carcinoma (IC) who underwent colonoscopic polypectomy from 1979 through 2008. We applied the histological criteria proposed by Morson to all the patients included in the series.
Results: we treated 24 polyps with IC and favorable histological criteria (FC) and 18 polyps showing unfavorable histological criteria (UC). All polyps with FC were treated by means of colonoscopic polypectomy. None of the patients showed signs of disease after a mean follow-up period o f 9.67 yrs. Patients with polyps with UC were recommended to undergo surgery. The presence of unfavorable histological criteria in the polypectomy sample was clearly associated with an unfavorable patient outcome and showed a 100% sensitivity level, a negative prognostic value (NPV) of 100%, and a false negative (FN) percentage of 0% for the prognosis of the disease. We found 12 sessile polyps (Haggitt s level 4). Colonoscopic polypectomy was the treatment employed in 9 out of 12 cases. All patients are free from disease (mean follow-up 7.3 yrs). If Haggitt s level criteria had been applied, all 12 patients would have undergone surgery. This means 58% more patients than following Morson s criteria.
Conclusions: Morson s criteria are considered an adequate diagnostic tool for the indication of surgery in patients with malignant adenomas. Haggitt s invasion levels do not accurately discriminate the necessity for surgery in case of malignant sessile lesions.