J Nucl Med. 2008; 49 (Supplement 1):256P
General Clinical Specialties: General Practice-OncologyGeneral Practice-Oncology Posters |
18F-FDG PET for evaluation of the response to concurrent chemoradiation therapy for rectal cancer
Hojin Cho1,
Arthur Cho1,
Taesung Kim1,
Wonjun Kang1,
Jongdoo Lee1 and
Mijin Yun1
1 Yonsei University Health System, Seoul, South Korea
1094
Objectives: To evaluate the potential role of PET using 18F-fluorodeoxyglucose (FDG) for evaluation of the response to concurrent chemoradiation therapy for rectal cancer.
Methods: Between July 2006 and August 2007, 26 consecutive patients with rectal cancer who underwent concurrent chemoradiation therapy were included. FDG PET was performed before and a month after the completion of chemoradiation therapy. Changes in 18F-FDG uptake were visually classified as positive or negative for residual disease. Pre- and post-chemoradiation SUVs were measured for semi-quantitative analysis. Surgery was performed after 4-5 weeks after the end of chemoradiotherapy and pathologic response was evaluated using Mandard’s criteria.
Results: Ten patients were graded as Mandard I. By visual analysis of PET images of the 10 patients, 9 showed no residual disease and one was positive for residual disease. Of the 16 patients with residual diseases on histopathology, PET correctly identified residual disease with areas of increased FDG uptake of primary tumors in all patients. By SUV analysis, there was a significant difference in SUV of primary tumors at post-chemoradiotherapy between patients with Mandard’s grade I (mean SUV 2.4±0.5) and the rest of the patients (mean SUV 4.9±2.0) (p<0.001). The reduction rate of SUVs between pre- and post-treatment scans was also significantly different between the patients with negative residual disease (mean SUV reduction rate 77.6±8.5) and those with positive residual disease (mean SUV reduction rate 58.8±16.4) (p=0.003).
Conclusions: SUV at post-treatment and a metabolic change between pre- and post-treatment FDG PET showed a high potential usefulness in the assessment of neo-adjuvant chemoradiation therapy of locally advanced rectal cancer.
