Alteration of strain ratio evaluated by transabdominal ultrasound elastography may predict the efficacy of preoperative chemoradiation performed for pancreatic ductal carcinoma: preliminary results.

Abstract We evaluated the usefulness of ultrasound-elastography (US-elastography) for prediction of therapy effect by measuring strain ratio (SR). Consecutive patients with resectable pancreatic ductal carcinoma who underwent US-elastography before and after neoadjuvant chemoradiation were included. Patients were classified into either response group or non-response group according to the histological evaluation of resected specimens. Serum carbohydrate antigen 19-9 (CA19-9), SR, and maximum standard uptake value (SUVmax) obtained from 18F-fuluoro-deoxy-D-glucose positron emission tomography and computerized tomography were measured before and after chemoradiation. Alteration rate of each parameter was compared between response group and non-response group. Seven patients met the inclusion criteria. One patient was excluded from pancreatectomy because liver metastasis was found by laparotomy. Serum CA19-9 was not elevated for 2 patients throughout the chemoradiation. Three patients were classified into response group and the remaining three into non-response group. Alteration rate of CA19-9 and SR was shown to be grater in response group (26.83 +/- 19.69 vs. 4.87 +/- 4.25, and 3.61 +/- 2.40 vs. 1.39 +/- 0.20, respectively), whereas that of SUVmax was not (1.56 +/- 0.43 vs. 2.11 +/- 0.10). Increase rate of SR may predict the therapy effect of neoadjuvant chemoradiation for patients with pancreatic ductal carcinoma, especially for patients without elevation of tumor markers.