BACKGROUND: The aim of this study was to investigate the association between plasma levels of homocysteine and the occurrence and progression of rectal cancer.

MATERIAL AND METHODS: The 320 study participants included healthy controls (n=80). and patients with rectal tumors (n=240), including 155 patients with rectal cancer, Stage I (n=32), Stage II (n=38), Stage III (n=50), and Stage IV (n=35), and patients with low-risk rectal adenomas (n=31), and high-risk rectal adenomas (n=54). All study participants had fasting blood samples taken, and plasma levels of homocysteine and carcinoembryonic antigen (CEA) were measured and compared. Receiver operating characteristic (ROC) curves were prepared to determine whether single, combined, or series levels of the two markers were diagnostic.

RESULTS: A significantly increasing trend in the plasma levels of homocysteine from the healthy controls, to the individuals with low-risk rectal adenoma, high-risk rectal adenoma, and Stage I–IV rectal cancer were found. There were no statistically significant differences in the area under the curve (AUC) between the two single factors of plasma homocysteine and CEA. The AUC showed that the use of combined or parallel measurement of plasma CEA and homocysteine had the greatest diagnostic associations.

CONCLUSIONS: Plasma levels of homocysteine were significantly associated with occurrence and progression of rectal cancer. The combined use of measurement of plasma homocysteine and CEA levels might have the potential to increase the diagnostic efficiency of screening for early rectal cancer.

Keywords: Carcinoembryonic Antigen, homocysteine, Rectal Neoplasms