Role of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography in predicting the pathologic response to preoperative chemoradiation therapy in patients with resectable T3 pancreatic cancer.

Abstract

The purpose of this study was to evaluate whether (18)F-fluorodeoxyglucose positron emission tomography in combination with computed tomography (FDG-PET/CT) could correctly predict the pathologic response to preoperative chemoradiation therapy (CRT) for resectable pancreatic cancer. Each of the 40 patients underwent FDG-PET/CT before and after preoperative CRT. The maximum standard uptake value (SUV) was measured for the primary tumor before and after preoperative CRT, defined as pre-CRT SUV and post-CRT SUV, respectively. The proportional alteration of the SUV decline (regression index) between post-CRT SUV and pre-CRT SUV was also calculated. These three indicators were associated with the pathologic response. Patients were classified as 21 responders and 19 nonresponders according to the histologic features. A pre-CRT SUV ≥ 4.7 was seen in 15 (71 %) of 21 responders and in 6 (32 %) of 19 nonresponders (p = 0.03). A regression index ≥ 0.46 was seen in 15 (71 %) responders and 5 (26 %) nonresponders (p = 0.01). A better pathological response can be expected for pancreatic cancer patients who have a high regression index (≥ 0.46) and a high pre-CRT SUV (≥ 4.7). The SUV measurement using FDG-PET/CT is a useful tool for predicting the pathologic response to preoperative CRT.