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Identifying High-Risk Patients with Early-Stage Colon Cancer

The stage of colon cancer at diagnosis is the most important determinant of prognoses and of chemotherapy decisions. However, accurate staging is limited by current tissue sampling and microscopic techniques. For example, up to 50 percent of patients who, by conventional staging techniques, have stage II cancer (confined to the bowel wall) at diagnosis have recurrences even after resection. In an attempt to go beyond microscopy for staging, researchers tested whether the expression of guanylyl cyclase C messenger RNA, an intestinal cell-specific mRNA, could identify patients at higher risk of recurrence.

All subjects in this case-control study had node-negative colorectal cancer, did not receive preoperative chemotherapy or radiation therapy, and had available lymph node specimens that could be evaluated adequately by reverse transcriptase polymerase chain reaction. The 10 cases had recurrences within 3 years of surgical treatment; the 11 controls were free of colorectal cancer recurrence for at least 6 years after surgery. The guanylyl cyclase C mRNA was not detected in any nodes from control patients or in nodes from 21 patients without colorectal cancer; in contrast, the mRNA was detected in all of the nodes from case patients.

Comment: The striking results in this study suggest that patients with stage II colon cancer can be separated into groups with high and low risks for recurrence. Because of the very small sample size and the retrospective nature of the study, these results will need confirmation before the test becomes routine. This study was partially sponsored by a maker of colorectal cancer detection kits.

— R Saitz

Published in Journal Watch General Medicine January 7, 2000

Citation(s):

Cagir B et al. Guanylyl cyclase C messenger RNA is a biomarker for recurrent stage II colorectal cancer. Ann Intern Med 1999 Dec 7 131 805-812.

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