[High-grade dysplasia as a risk factor of metachronous advanced colorectal neoplasms in patients with advanced adenomas].

Background: Patients with advanced adenomas (AA) have a high risk of developing advanced colorectal neoplasms. Therefore, shorter monitoring intervals have been recommended in this patient subgroup. High grade dysplasia (HGD) is the main marker of cancer transformation. However, its predictive value for developing advanced neoplams in patients with advanced adenoma is unknown.
Aim: To investigate if HGD increases the risk for developing advanced neoplasms in patients with AA.
Methods: Between January 1996 and December 1997 every patient with an AA endoscopically resected were considered for inclusion. Patients with a history of colorectal cancer (CRC), inflammatory bowel disease, familial adenomatous polyposis or patients who met the Amsterdam criteria, and those without colonoscopic monitoring were excluded. We assessed the development of advanced neoplasms during the study period.
Results: 71 patients were included and classified into 2 groups, depending on the presence (n = 49) or lack (n = 22) of HGD in the initial colonoscopy. The probability of developing advanced neoplasms (log rank, p = 0.47; Breslow, p = 0.58) or AA with HGD (log rank, p = 0.47; Breslow, p = 0.53) in the study period was similar between both groups. The number of metachronic polyps (p = 0.67), adenomas (p = 0.73), AA (p = 0.93) and AA with HGD (p = 0.88) was also similar.
Conclusion: The risk of developing advanced neoplasms is not different between AA with HGD and those with other characteristics of AA (villous pattern and larger than 1 cm). Therefore, changes in monitoring intervals are not warranted.