Wild-Type KRAS and BRAF Could Predict Response to Cetuximab in Chinese Colorectal Cancer Patients

Objective: To analyze the relationship between KRAS, BRAF mutations and the response toCetuximab in Chinese colorectal cancer patients.

Methods: A total of273 Chinese colorectal cancer patients were evaluated for KRAS and BRAF mutations by Sanger sequencing. Among them, 59 patients with metastatic colorectal cancer (mCRC) were treated with Cetuximab in combination with chemotherapy from August 2005 to July 2009. Statistical analysis was conducted to assess the relationship between KRAS, BRAF mutations and the response or survival of 59 mCRC patients.

Results: KRAS and BRAF mutation rates were 38.5% (105/273) and 5.1% (14/273), respectively, and KRAS/BRAF mutations were mutually exclusive. Among 59 patients treated with Cetuximab plus chemotherapy, KRAS and BRAF mutations were identified in 11and 5 patients, respectively. The response rates and median progression-free survivals (PFS) in KRAS wild-type and mutant patients were 35.4% (17/48) vs. 9.1% (1/11) (P=0.054) and 153 days vs. 99 days (P=0.01), respectively.Also, the response rates and median PFS in BRAF wild-type and mutant patients were 37.2% (16/43) vs. 20% (1/5) (P=0.016) and 138 days vs. 90 days (P=0.036), respectively.

Conclusion: Besides KRAS, assessing BRAF mutation should also be required to select patients eligible for Cetuximab. Further prospective evaluation in large samples should be performed to confirm these preliminary findings.