Adapted Choi response criteria for prediction of clinical outcome in locally advanced gastric cancer patients following preoperative chemotherapy

Background. Tumor response to chemotherapy has traditionally been assessed by using Response Evaluation Criteria in Solid Tumors (RECIST) based on changes in tumor size alone. However, adapted Choi criteria, which incorporate volumetric tumor attenuation in addition to tumor size, have been reported more predictive of chemotherapeutic efficacy than RECIST in some studies. Purpose. To examine the usefulness of adapted Choi criteria in predicting clinical survival in locally advanced gastric cancer patients treated with cytotoxic drugs. Material and Methods. A total of 48 histologically proven gastric cancer patients who received neoadjuvant chemotherapy and surgery were involved. Pre- and post-chemotherapy short-axis diameter and volumetric mean tumor attenuation of target lymph nodes on contrast-enhanced CT images were measured. Tumor response was assessed by using both RECIST and adapted Choi criteria, and was correlated with progression-free survival (PFS) and overall survival (OS). Results. Significant decrease was observed in the sum of short-axis diameters and tumor attenuation of metastatic lymph nodes between baseline and post-chemotherapy CT images. The inter-observer agreement for both parameters was good. The PFS and OS of 17 RECIST responders were identical with that of 28 adapted Choi responders (P = 0.855 and 0.913, respectively). PFS and OS of 31 RECIST non-responders were significantly prolonged compared to that of 20 adapted Choi non-responders (P = 0.018 and 0.042, respectively). To the 11 RECIST stable disease (SD) but adapted Choi partial response (PR) patients, the PFS and OS were similar to the survival of 17 RECIST PR patients (P 0.785 and 0.838, respectively), but significantly prolonged compared to that of the 12 both RECIST and adapted Choi criteria SD patients (P < 0.001 and P 0.004, respectively). Conclusion. Adapted Choi criteria might be helpful to predict PFS and OS in locally advanced gastric cancer patients following chemotherapy