Recent chemotherapy reduces the maximum-standardized uptake value of 18F-fluoro-deoxyglucose positron emission tomography in colorectal cancer.
OBJECTIVE
The aim of this study was to evaluate the influence of recent chemotherapy on the patterns of the maximum-standardized uptake value (M-SUV) and sensitivity of (18)F-fluoro-deoxyglucose positron emission tomography/computed tomography ((18)F-FDG-PET/CT) in colorectal cancer.


METHODS
We retrospectively analyzed the FDG-PET/CT of 509 patients who underwent surgery for colorectal cancer. Subgroup analysis was performed according to chemotherapy status; 401 patients were not treated with chemotherapy and 108 patients were treated with chemotherapy within 6 months prior to surgery. Pathologic analysis of the surgical specimen was used as the gold standard.


RESULTS
The M-SUV was significantly lower in patients treated with chemotherapy than in those not treated with chemotherapy in pathologically confirmed same stages of disease. The difference in the sensitivity of the M-SUV according to chemotherapy status was greatest using a cutoff M-SUV value of 6.4 (p<0.001). The longest diameter of the primary tumor was the most important factor that correlated with M-SUV of the primary tumor irrespective of the chemotherapy effect (p<0.001). The M-SUV of the primary tumor was not an independent predictor of lymph node metastasis in colorectal cancer.


CONCLUSIONS
The results indicate that the M-SUV of FDG-PET/CT should be interpreted in the context of concurrent chemotherapy.
Department of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul, Korea.
Minjong
M
Lee
Department of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul, Korea.
Tae Sung
TS
Yeum
Department of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul, Korea, Departments of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
Ji Won
JW
Kim
Departments of Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea.
Sohee
S
Oh
Department of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul, Korea.
Shin Ae
SA
Lee
Department of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul, Korea.
Hong Ran
HR
Moon
Department of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul, Korea.
Young Hoon
YH
Choi
Department of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul, Korea.
Yoo Min
YM
Han
Department of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul, Korea.
Ji Min
JM
Choi
Department of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul, Korea.
Dong Kee
DK
Jang
D000368:Aged; D000970:Antineoplastic Agents / Q000009:adverse effects*; D059186:Chemoradiotherapy, Adjuvant / Q000009:adverse effects; D017024:Chemotherapy, Adjuvant / Q000009:adverse effects; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000494:pharmacology*; D006801:Humans; D008297:Male; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals / Q000494:pharmacology*; D012189:Retrospective Studies
D000970:Antineoplastic Agents; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
Colorectal neoplasms; Drug therapy; FDG-PET/CT