Preliminary report on pathology of colorectal cancer in Poland in 1995 and 1975: is it still the same disease?

Abstract

Over past three decades in Poland we have seen a steady increase in the incidence of colorectal cancer. It is unclear whether this phenomenon is associated with changes in biology of the disease. In the present study we compared basic clinical data and pathological features of colorectal carcinomas submitted as resection specimens to a single institution in 1975 (n=76) and 1995 (n=106). We found a significant increase in sigmoid tumors (15.8% in 1975, 34.9% in 1995, P=0.0028), a decline in the frequency of mucinous carcinomas (22.4% in 1975, 7.5% in 1995, P=0.0041), and reversed distribution of low- and high-grade tumors (more high-grade than low-grade carcinomas in 1975, the opposite in 1995). We observed trends toward more pronounced peritumoral desmoplastic response, less prominent chronic peritumoral inflammatory infiltrate, and more frequent perineural invasion. The 1995 patients were on average significantly older at surgery (59 years in 1975, 64 years in 1995, P=0.02) and had smaller tumors (max. diameter=5.49 cm in 1975, 4.27 cm in 1995, P=0.0018). There were no differences in distribution of tumor stage, patient's sex, type of infiltrating margin formed by carcinomas, relative amount formed by the solid tumor component, invasion of veins and lymphatics, or presence of an adenoma contiguous with a carcinoma. Differences between 1975 and 1995 cases observed in our material probably reflect the changing biology of colorectal carcinoma in Poland. Mucinous, high-grade, proximal tumors, surrounded by prominent chronic inflammatory infiltrate, diagnosed in relatively younger subjects are associated with familial and sporadic cancers due to widespread genomic instability (replication error positive or RER(+) phenotype). We conclude that in Poland the APC/K-ras/p-53 carcinogenesis pathway is becoming even more important than the carcinogenesis characterized by RER(+) tumors. This study is a starting point for further investigations aimed at confirming this hypothesis.