[18f]-Fluorodeoxyglucose-Positron Emission Tomography for the Assessment of Histopathologic Response and Prognosis After Completion of Neoadjuvant Chemotherapy in Gastric Cancer
Daniel Vallbohmer*1, Arnulf H. HöLscher1, Paul M. Schneider1,2, Matthias Schmidt3, Markus Dietlein3, Elfriede Bollschweiler1, Stephan E. Baldus4, Jan Brabender1, Ralf Metzger1, Stefan Monig1
1Department of General, Visceral and Cancer Surgery, University of Cologne, Cologne, Germany; 2Department of Visceral and Transplantation Surgery, University Hospital Zurich, Zurich, Switzerland; 3Department of Nuclear Medicine, University of Cologne, Cologne, Germany; 4Department of Pathology, University of Dusseldorf, Cologne, Germany
Background: Neoadjuvant chemotherapy is frequently applied to improve the prognosis of patients with locally advanced gastric cancer. However, only a major histopathological response will provide a survival benefit in these patients. Recent studies suggest that [18F]-fluorodeoxyglucose-positron emission tomography (FDG-PET) significantly correlates with histopathological response and survival in patients with gastroesophageal adenocarcinomas undergoing neoadjuvant chemotherapy followed by surgical resection. Therefore, we evaluated the potential of FDG-PET) for the assessment of histopathologic response and prognosis in the multimodality treatment of patients with gastric cancer.Methods: Study patients were recruited from a prospective clinical observation trial on neoadjuvant chemotherapy for gastric cancer between 1997 and 2007. Forty-two patients with locally advanced gastric cancer (cT3-4, Nx, M0) were included (33 men, 9 women; median age 57 years). All patients received neoadjuvant chemotherapy according to the PLF-protocol (cisplatin, leucovorin, 5-FU; 2 cycles over 6 weeks) and subsequently 40 patients underwent standardized total gastrectomy while 2 patients received definitive chemotherapy because of tumor progression. Histomorphologic regression was defined as major histopathological response when resected specimens contained less than 10 % vital residual tumor cells. FDG-PET was performed before and 2 weeks after the end of neoadjuvant chemotherapy with assessment of the intratumoral FDG-uptake [pre-treatment standardized uptake value (SUV1); post-treatment standardized uptake value (SUV2); percentage change (SUVΔ%)]. These variables were correlated with histopathological response and survival.Results: Neoadjuvant chemoradiation led to a significant reduction of intratumoral FDG-uptake (p=0.0006). However, no significant correlations between SUV1, SUV2 or SUVΔ% and histopathological response or prognosis were found. Histomorphological tumor regression was confirmed as an important prognostic factor (p=0.04; log-rank test).Conclusion: Our study does not support recent reports that the metabolic response by FDG-PET is associated with histomorphological response or survival in patients with gastric cancer following neoadjuvant therapy and gastrectomy.
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