gms | German Medical Science

27. Deutscher Krebskongress

Deutsche Krebsgesellschaft e. V.

22. - 26.03.2006, Berlin

Assessment of Metabolic Response to Preoperative Short Course Radiotherapy in Locally Advanced Rectal Cancer: Value of F-18 Fluorodeoxyglucose Positron Emission Tomography

Meeting Abstract

  • corresponding author presenting/speaker Robert Siegel - Klinik für Chirurgie und Chirurgische Onkologie, Robert-Rössle-Klinik im Helios Klinikum Berlin, Charité, Universitätsmedizin Berlin, Campus Buch, Deutschland
  • Stefan Dresel - Nuklearmedizinische Klinik, Helios Klinikum Berlin-Buch
  • Bernhard Gebauer - Diagnostische und interventionelle Radiologie, Robert-Rössle-Klinik im Helios Klinikum Berlin, Charité, Universitätsmedizin Berlin, Campus Buch
  • Michael Hünerbein - Klinik für Chirurgie und Chirurgische Onkologie, Robert-Rössle-Klinik im Helios Klinikum Berlin, Charité, Universitätsmedizin Berlin, Campus Buch
  • Stephan Koswig - Strahlentherapie, Robert-Rössle-Klinik im Helios Klinikum Berlin, Charité, Universitätsmedizin Berlin, Campus Buch
  • Peter Michael Schlag - Klinik für Chirurgie und Chirurgische Onkologie, Robert-Rössle-Klinik im Helios Klinikum Berlin, Charité, Universitätsmedizin Berlin, Campus Buch

27. Deutscher Krebskongress. Berlin, 22.-26.03.2006. Düsseldorf, Köln: German Medical Science; 2006. DocPO604

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dkk2006/06dkk712.shtml

Veröffentlicht: 20. März 2006

© 2006 Siegel et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

F-18 Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) as a molecular imaging technique has been widely applied in oncology offering a complementary approach to anatomical imaging. There is increasing evidence that FDG-PET may reliably monitor response to multimodality treatment in rectal cancer. The aim of this prospective study was to evaluate the role of FDG-PET in preoperative short course radiotherapy (RT). FDG-uptake was assessed and compared to MR imaging (MRI) and endorectal ultrasound (EUS) in rectal cancer patients after RT. 17 consecutive patients (median age 64 yrs) scheduled for preoperative RT (5x 5 Gy) between July 2004 and November 2005 were included. Only patients with locally advanced rectal cancer staged uT2 N+ or uT3 Nany were eligible for RT. FDG-PET, MRI and EUS were performed before and after preoperative RT, followed by complete resection of the tumor. Maximum standardized uptake value (SUVmax) was measured and compared to both the results of MRI and EUS and to histopathological assessment. FDG-PET’s SUVmax significantly decreased by 40% (median) after RT. SUVmax was reduced from median 9.5 (SD 5.0) before commencing RT to 5.8 (SD 3.3) at the end of preoperative radiation. Using a threshold of 40% SUVmax reduction to define a meaningful decrease in FDG-uptake, 9/17 patients revealed functional response after RT. Histopathological tumor regression grade revealed a low response in all irradiated specimen. There was no correlation between SUVmax reduction and regression grade. Clinical restaging by EUS and MRI could not precisely predict histopathological features after RT. Our study suggests that FDG-PET is able to demonstrate metabolic response of rectal cancer to preoperative RT. These results are comparable to what has already been shown for the combined radiochemotherapy approach. In contrast to anatomic imaging and conventional histopathology, which are not qualified to monitor short-term radiation effects, the decrease of SUVmax may serve as a surrogate marker. Although radiation biology may not precisely explain the observed metabolic response, our results indicate that FDG-PET is able to detect early changes upon tumor specific therapy and could become a useful method in predicting response for multimodality therapy in rectal cancer. In addition to further research in establishing molecular prognostic factors, long term follow-up of these patients is warranted to correlate the FDG-PET findings with survival.