Purpose
Adjuvant chemotherapy with uracil- tegafur has been demonstrated to prolong survival among patients with resected lung adenocarcinomas. Epidermal growth factor receptor ( EGFR) mutations have been reported to be present in lung adenocarcinomas. The present study evaluated whether the EGFR status could be used as a biologic predictor of the outcome of adjuvant chemotherapy with uracil- tegafur.
Patients and Methods
The EGFR mutational status of 187 patients with resected lung adenocarcinomas was determined using a polymerase chain reaction - based assay for EGFR exons 19 and 21; the results were then correlated with the effect of adjuvant uracil- tegafur chemotherapy on survival. The antiproliferative effect of fluorouracil ( FU) on adenocarcinoma cell lines with EGFR wild-type or mutant type status was examined by measuring the inhibitory concentrations at 50% ( IC(50)s).
Results
Among the 187 patients, 68 received uracil- tegafur as adjuvant chemotherapy, and 119 were not treated with any chemotherapeutic agents. EGFR mutations were present in 79 patients ( 43%). Overall, the adjuvant chemotherapy with uracil- tegafur significantly prolonged survival compared with the control group ( hazard ratio = 0.38; P =.005). The survival benefit of adjuvant chemotherapy with uracil- tegafur was also examined after stratifying the patients according to EGFR mutation status. Adjuvant chemotherapy significantly prolonged survival among patients with EGFR wild- type tumors ( hazard ratio = 0.34; P =.013) but not among patients with EGFR mutant tumors. In an in vitro experiment, the IC(50)s of EGFR mutant cells to FU were higher than those of wild-type cells, indicating that EGFR wild- type cells are more sensitive to FU than mutant cells.
Conclusion
EGFR status influenced the effect of adjuvant chemotherapy with uracil- tegafur. Adjuvant chemotherapy could be customized based on EGFR status.