Marker Helps Predict Response to 5-FU Chemotherapy in Early Colorectal Cancer

Marker Helps Predict Response to 5-FU Chemotherapy in Early Colorectal Cancer

According to an article recently published in the journal Gut, a molecular marker referred to as mismatch repair (MMR) deficiency may help to predict which patients will respond to chemotherapy including 5-fluorouracil (5-FU) for treatment of early colorectal cancer.

Colorectal cancer is the second leading cause of cancer-related deaths in the U.S. Stage II and III colorectal cancer refers to cancer that has spread from its site of origin, but not to distant sites in the body. Chemotherapy including the agent 5-FU remains an important component in the treatment regimen for stages II-III colorectal cancer.

Since anticancer responses vary among patients treated for cancer, researchers continue to evaluate potential “markers” that may indicate which patients benefit from certain therapies. This will ultimately allow therapeutic approaches to be individualized, providing optimal care for all patients.

Researchers from Spain recently conducted a study to evaluate the MMR marker to determine if it could help predict which patients with early colorectal cancer would benefit from treatment with 5-FU.

This study included 260 patients with stages II or III colorectal cancer who underwent surgery. A group of patients then underwent treatment with 5-FU; another group did not receive further chemotherapy. Their cancers were evaluated for the MMR marker, and they were followed for a median of nearly 730 days.

  • Among patients who did not have the MMR marker (these patients are referred to as MMR competent), overall survival among those who received chemotherapy was 87% compared to only 73.5% for those who did not receive chemotherapy.
  • Among patients who did have the MMR marker (referred to as MMR deficient), overall survival was not significantly different between those who received chemotherapy and those who did not receive chemotherapy (89.5% vs. 82.4%, respectively).

The researchers concluded that among patients with stages II-III colorectal cancer, the MMR marker can help predict which patients will achieve a benefit from treatment with the chemotherapy agent 5-FU. Those who are MMR competent have improved survival with the addition of 5-FU to their treatment regimen, while those who are MMR deficient do not appear to derive any benefit from additional treatment with 5-FU. However, it is important for each patient to discuss their individual risks and benefits of receiving treatment with chemotherapy, as further confirmatory studies are necessary to bring the MMR marker into clinical practice.

Reference: Jover R, Zapater P, Castells A, et al. Mismatch Repair Status in the Prediction of Benefit from Adjuvant Fluorouracil Chemotherapy in Colorectal Cancer. Gut. 2006; 55:848-855.

Related News: Two-Thirds of Patients with Stage III Colon Cancer Receive Recommended Chemotherapy (12/7/2005)

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