Delayed (18)F-FDG PET for detection of paraaortic lymph node metastases in cervical cancer patients.
This prospective study investigated the usefulness of dual-phase (18)F-FDG PET scans (40 min and 3 h) in detecting paraaortic lymph node (PALN) metastasis for cervical cancer.


METHODS
One hundred four consecutive cervical cancer patients (International Federation of Gynecology and Obstetrics staging Ib-IVb, recurrent or persistent tumors) were included. All patients received a whole-body (18)F-FDG PET scan at 40 min and an additional scan from the T11 level to the inguinal region at 3 h after injection of 370 MBq (18)F-FDG. The maximum standardized uptake value (SUV) and retention index (RI [%], obtained by subtracting the normalized SUV value obtained at 40 min from that at 3 h) of the lesions were determined.


RESULTS
In all, 38 of the 104 patients were confirmed to have PALN metastases. For 31 patients (81.6%) with 13 upper (L1-L2 level) and 30 lower (L3-L4 level) PALNs, these metastases were detected with the 40-min scan. In addition, for 7 patients (18.4%) with 7 lower PALNs, metastases were found with the 3-h scan (RI = 12.6%). Two patients (3.0%) had 2 false-positive lesions initially (40 min) but were classified as benign with the 3-h scan. The sensitivity, specificity, and accuracy of (18)F-FDG PET scans at 40 min were 81.6%, 97.0%, and 91.3%, respectively. These quantities were all 100% when both the 40-min and 3-h scans were taken together. Eight patients (21.1%) had their treatment planning changed. We divided the 38 patients into 2 subgroups. Subgroup A included those with either only upper or only lower PALN metastases, and subgroup B included those with both upper and lower PALN metastases. In subgroup A, the SUV values were greater in the upper than in the lower PALNs in both the 40-min and 3-h images (P = 0.077). In subgroup B, there was no significant difference of SUV values between upper and lower PALNs in the 40-min (P = 0.433) and 3-h (P = 0.937) images.


CONCLUSIONS
Our results showed that an additional 3-h scan is helpful for PALN detection of cervical cancer patients. A delayed image (3 h) is especially useful for lower PALN metastases.
Ma
Shih-Ya
SY
Department of Nuclear Medicine, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan.
See
Lai-Chu
LC
Lai
Chyong-Huey
CH
Chou
Hung-Hsueh
HH
Tsai
Chien-Sheng
CS
Ng
Koon-Kwan
KK
Hsueh
Swei
S
Lin
Wuu-Jyh
WJ
Chen
Jenn-Tzong
JT
Yen
Tzu-Chen
TC
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D011446:Prospective Studies; D013997:Time Factors; D014055:Tomography, Emission-Computed; D002583:Uterine Cervical Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology
D019788:Fluorodeoxyglucose F18