Usefulness of serum protein profiling for prediction of preoperative chemoradiosensitivity of esophageal cancer

We examined whether serum protein profiling is a reliable index for prediction of therapeutic efficacy of preoperative chemoradiotherapy (PCRT) in advanced esophageal cancer compared with evaluation of the efficacy of conventional clinical examination. We entered 42 patients who received PCRT and surgery between 1998 and 2002 into this study. Serum protein profiling was performed using the preoperative serum of the patient to select the marker set that enabled the efficacy of PCRT to be evaluated accurately. The efficacy of PCRT was predicted with the marker set, and the sensitivity, specificity and accuracy of the method were calculated based on evaluation of the efficacy by pathological examination. Similarly, therapeutic efficacy was also predicted based on evaluation of the efficacy of conventional clinical examination, and the results were compared with those of prediction by serum protein profiling. The correlation between each predictive examination and outcome was evaluated. The sensitivity, specificity and accuracy of prediction of therapeutic efficacy of PCRT by serum protein profiling were 90.9, 100 and 93.3%, respectively. In clinical examination, prediction of the efficacy of PCRT by three methods was as follows: by esophagography, sensitivity 76.0%, specificity 17.6%, accuracy 52.4%; by endoscopy, sensitivity 80.0%, specificity 11.8%, accuracy 52.4%; by computed tomography, sensitivity 60.0%, specificity 47.1%, accuracy 54.8%, respectively. These results demonstrated the superiority of serum protein profiling in predicting the therapeutic efficacy of PCRT compared with conventional clinical examination. Moreover, serum protein profiling was the only significant prognostic factor as regards the correlation with outcome by multivariate analysis.