Prognostic Significance of Hereditary Predisposition on the Outcome of Colorectal Cancer as Expressed by Increased in Vitro Tetraploidy

Seventy colorectal cancer patients operated on in the period 1981–1984 were consecutively investigated for in vitro tetraploidy in dermal fibroblasts, as an increased number of tetraploids is considered a marker of genetic predisposition for colorectal cancer. The difference in disease-free survival rates of increased (IVT⁺) and normal (IVT^?) in vitro tetraploidy was not statistically significant (0.1 < p < 0.2), but the decrease in the disease-free survival rate of IVT⁺ was 1.6 times that of IVT^?. To exclude the influence of other prognostic factors, a Cox multivariate regression analysis was used, with Dukes C carcinoma and poor differentiation as co-variables for IVT⁺. In this analysis IVT⁺ did not show any independent prognostic significance. A genetic predisposition for colorectal cancer, as expressed by the presence of IVT⁺ in skin fibroblasts, does not seem to influence the survival of patients with colorectal cancer.