The presence of guanylyl cyclase 2C (GUCY2C) in regional lymph nodes is an independent predictor of disease recurrence in patients with colorectal cancer, according to researchers at Thomas Jefferson University. They say that GUCY2C can detect occult metastases in lymph nodes.
“One of the unmet needs in colorectal cancer is an accurate staging method to determine how far the disease has spread,” says Scott A. Waldman, M.D., Ph.D., director of the gastrointestinal malignancies program at the Kimmel Cancer Center at Jefferson. “The current standard method, histopathology, is imperfect since it only involves looking at a very small sample of the regional lymph nodes under a microscope. There is no way to know whether occult metastases are present in the rest of the tissue.”
The team examined the association of colorectal cancer recurrence with occult lymph node metastases detected by measuring GUCY2C mRNA using RT-PCR. The study included 257 patients with pN0 colorectal cancer, according to current standards, who provided 2,570 lymph nodes for biopsy and GUCY2C mRNA analysis. Patients were followed up for a midpoint of 24 months for disease recurrence or death.
The scientists found that 87.5% had lymph nodes that were positive for GUCY2C. Among those patients, 20.9% developed recurrent disease. By comparison, 6.3% of the patients whose lymph nodes were negative for GUCY2C developed recurrent disease.
Additionally, patients who expressed GUCY2C had a shorter time to recurrence and a shorter disease-free survival. The prognostic value of the marker persisted even after a multivariate analysis that took other known prognostic factors into account, according to the researchers.
“Beyond predicting disease recurrence, detecting this biomarker could be useful for identifying patients who might benefit from treatment with adjuvant chemotherapy, which is specifically given to patients with node-positive disease,” Dr. Waldman adds.
The study appears in the February 18 issue of JAMA.
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