The number of potential gateways determines prognostic value of tumour deposits in colon cancer.

Tumour deposits (TD) are a crucial biomarker in colorectal cancer, closely associated with nearby structures such as blood vessels, lymphatic vessels, and peripheral nerves. These anatomical structures serve as pathways that facilitate the spread of tumour cells throughout the body. This study aims to investigate how TD access these anatomical gateways and how these variations impact patient survival. We analysed colon carcinoma patients who underwent surgery at Radboud University Medical Centre between 1986 and 2012 for the presence of TD. Using serial sections and immunohistochemistry with four different antibodies (CD34, D2-40, S100, and elastic van Gieson), we examined the presence and distribution of TD access to surrounding anatomical structures, including blood vessels, lymphatic vessels and peripheral nerves. In 127 patients, 280 TD were examined. Of these, 112 TD (40%) had multiple access points, 109 TD (39%) had a single access point, and 59 TD (21%) had no discernible access point. More than half of the TD (57%) demonstrated haematovascular invasion. Patients with TD featuring a single access point had a better prognosis compared to those with multiple access points (5-year overall survival, p=0.025; 5-year disease-free survival, p=0.005). TD are a heterogeneous biomarker characterised by various access points, with haematovascular invasion being the most common. Our study highlights a direct correlation between the number of TD access points and patient outcomes, indicating that an increase in access points is linked to a poorer prognosis.