Predictive Value of 18-Fluoro-Deoxy-Glucose-Positron Emission Tomography (18F-FDG-PET) in the Identification of Responders to Chemoradiation Therapy for the Treatment of Locally Advanced Esophageal Cancer

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Abstract
Objective: To evaluate the utility of 18F-FDG-PET in predicting response to concomitant chemoradiation in locally-advanced esophageal cancer. Summary Background Data: Approximately 25% of esophageal cancer patients experience a pathologic complete response (pCR) to preoperative chemoradiation therapy. Computed tomography, endoscopy, and endoscopic ultrasound are unable to identify patients experiencing a pCR. Growing evidence supports the use of 18F-FDG-PET in the staging of esophageal cancer in its ability to detect occult metastatic and lymph nodal disease. The identification of patients with a pCR to chemoradiation could potentially spare those patients the morbidity associated with a resection. Methods: Eligibility criteria included T3-T4N0M0 or T1-T4N1M0 esophageal cancer. Patients underwent an initial 18F-FDG-PET before treatment and then repeated 4 to 6 weeks after chemoradiation, prior to the esophagectomy. Chemoradiation consisted of: cisplatinum, 5-fluorouracil, and radiation to a median dose of 50.4 Gy. Pathologic response was determined from a systematic review of the esophagectomy specimens. Results: Sixty-four patients have completed therapy to date. Response was as follows: pCR 27%, pathologic residual microscopic (pCRmicro) 14.5%, partial response 19%, and stable or progressive disease 39.5%. A pretreatment standardized uptake value (SUVmax1hour) ≥15 was associated with an observed 77.8% significant response (pCR + pCRmicro) compared with 24.2% for patients with a pretreatment SUVmax1hour P = 0.005). Significant response was observed in 71.4% of patients with a decrease in SUVmax1hour ≥10 compared with 33.3% when the SUVmax1hour decreased P = 0.004). Conclusions: Pretreatment and posttreatment 18F-FDG-PET can be useful for predicting significant response to chemoradiation in esophageal cancer. These data should be considered in evaluation of patients for esophagectomy after chemoradiation.