Transitional mucosa and survival in human colorectal cancer.

The mucosa in 100 segments of colon and rectum resected for cancer were examined using light microscopy and histochemical techniques. The extent of abnormal or transitional mucosa was defined for each case. Transitional mucosa was present in 93 of 95 adenocarcinomas and one malignant melanoma. The average total length of transitional change was 3.4 cm the maximum length was 19.5 cm. An inverse correlation was observed between the survival and the length of transitional mucosa around locally invasive (Dukes' B) carcinomas (P = 0.005). This may be related to increased amounts of sialic acid in transitional mucosa and the ability of sialic acid to depress tumor immunogenicity. The raised levels of sialic acids in transitional mucosa may have practical value in assessment of prognosis in colorectal cancer.