[Risk factors for lymphatic metastasis from pT1 colorectal adenocarcinoma]

During the last 20 years, endoscopic removal of colorectal adenoma has become widely accepted as a replacement for removal by open surgery. Even colorectal adenocarcinomas are not excluded. The key question is when surgical treatment should still be preferred over endoscopic removal as the primary treatment. One good indicator is the frequency of lymph node metastasis, which should be compared with the overall risk involved in the surgical procedure itself. Histological examination allows subdivision of early colorectal adenocarcinomas into low-risk and high-risk groups. Classical parameters for a high-risk situation are lymphatic invasion, poor differentiation, and incomplete removal (R1). Additional risk factors that have recently been discussed are infiltration into the lower third of the submucosal layer (sm3) and dissociation (budding) of the tumour cells at the invasion front. Drawing on the literature and an analysis of our own patients, we demonstrate a positive correlation between these new markers and an elevated risk of the presence of lymph node metastasis.