LAUSR

The incidence and mortality of esophagogastric (EG) adenocarcinoma have been progressively increasing, particularly in Western countries. Genomically, these tumors are characterized by chromosomal instability, marked aneuploidy, and a high rate of TP53 mutations, contributing to the aggressive biology and high metastatic potential of this disease. Despite aggressive multimodality perioperative therapy with chemotherapy or chemoradiotherapy, many patients experience disease recurrence, and therefore [F]fludeoxyglucose (FDG) positron emission tomography (PET) imaging plays a role in the staging of and treatment planning for patients with EG cancer. In particular, FDGPET imaging and its fusion with computed tomography (PET-CT) are helpful for ruling out metastatic disease in up to 20% of patients who are candidates for surgical resection. In a multicenter prospective study, the use of PET-CT for the staging of potentially resectable esophageal adenocarcinoma led to clinically important changes in staging in 24% of 491 patients. Several studies also have shown that early assessment of treatment response to chemotherapy or chemoradiotherapy by PET (defined as a ≥35% reduction in the standardized uptake value [SUV] between the baseline scan and a repeat scan) is highly correlated with patient survival. However, in a retrospective Memorial Sloan Kettering Cancer Center series of 192 patients with gastric cancer who completed preoperative chemotherapy, PET-CT failed to add prognostic information beyond histological tumor and lymph node status assessment performed by pathologists. Furthermore, in a multivariate analysis, the maximum SUV change on PET after the completion of chemotherapy was not found to be an independent predictor of disease-specific survival in patients with gastroesophageal junction adenocarcinoma (P = .20) or gastric adenocarcinoma (P = .66). In a series from The University of Texas MD Anderson Cancer Center of 73 patients with esophageal cancer (88% with adenocarcinomas), although the SUV of <3 on postchemoradiotherapy PET correlated with pathologic complete response (pCR) (P = .03), PET failed to rule out microscopically residual tumor in approximately 18% of patients. Accordingly, in our practice, PET is not used to select patients for nonoperative management after chemoradiotherapy. The MUNICON (Metabolic Response Evaluation for Individualisation of Neoadjuvant Chemotherapy in Oesophageal and Oesophagogastric Adenocarcinoma) trial confirmed the prognostic significance of early-assessment PET in patients with locally advanced gastroesophageal junction adenocarcinoma. Remarkably, after 1 cycle of chemotherapy, approximately 51% of patients in this cohort were PET nonresponders and were “rescued” by proceeding directly to surgery. In a previous study, the median recurrence-free period and median survival after continuing chemotherapy in metabolically nonresponsive patients with tumor stages and preoperative chemotherapy that were similar to those in the MUNICON study were 10 months and 18 months, respectively. Patients in the MUNICON study with a metabolic response (49%) continued chemotherapy for 12 weeks and then proceeded to surgery. The overall survival of PET nonresponders was significantly worse compared with that of PET responders (median, 25.8 months vs not reached; hazard ratio, 2.13 [95% confidence interval, 1.14-3.99]). Withdrawing ineffective chemotherapy does not worsen outcomes, Sebastian Mondaca, MD Department of Medicine, Memorial Sloan Kettering Cancer Center, Weill Cornell Medical College, New York, New York