The role of PET/CT in detection of gastric cancer recurrence.
BACKGROUND
In the course of surveillance of gastric cancer recurrence after curative resection, contrast CT scan is used in general. However, new findings from CT scan are not always confirmatory for the recurrence. In this case, we usually use short-term follow up strategy or therapeutic intervention with clinical decision. Recently, the use of fusion Positron Emission Tomography/Computed Tomography (PET/CT) is increasing. The purpose of this study is to evaluate the efficacy and usefulness of PET/CT for detecting recurrence of gastric cancer after curative resection.


METHODS
Fifty two patients who received curative resection of gastric cancer and had undergone PET/CT and contrast CT for surveillance of recurrence until Dec 2006 in Seoul National University Hospital were analyzed retrospectively. Recurrence of gastric cancer was validated by histologic confirmation (n = 17) or serial contrast CT follow up with at least 5 month interval (n = 35). McNemar's test and Fisher's exact test were used to evaluate sensitivity and specificity of PET/CT and contrast CT.


RESULTS
Of 52 patients, 38 patients were confirmed as recurrence. The sensitivity was 68.4% (26/38) for PET/CT and 89.4% (34/38) for contrast CT (p = 0.057). The specificity was 71.4% (10/14) and 64.2% (9/14), respectively (p = 1.0). In terms of the recurred sites, the sensitivity and specificity of PET/CT were similar to those of contrast CT in all sites except peritoneum. Contrast CT was more sensitive than PET/CT (p = 0.039) for detecting peritoneal seeding. Additional PET/CT on contrast CT showed no further increase of positive predictive value regardless of sites. Among 13 patients whose image findings between two methods were discordant and tissue confirmation was difficult, the treatment decision was made in 7 patients based on PET/CT, showing the final diagnostic accuracy of 42.8% (3/7).


CONCLUSIONS
PET/CT was as sensitive and specific as contrast CT in detection of recurred gastric cancer except peritoneal seeding. However, additional PET/CT on contrast CT did not increase diagnostic accuracy in detection of recurred gastric cancer. Further studies are warranted to validate the role of PET/CT in detection of gastric cancer recurrence.
Sim
Sung Hoon
SH
Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea. boron@hanmail.net
Kim
Yu Jung
YJ
Oh
Do-Youn
DY
Lee
Se-Hoon
SH
Kim
Dong-Wan
DW
Kang
Won Jun
WJ
Im
Seock-Ah
SA
Kim
Tae-You
TY
Kim
Woo Ho
WH
Heo
Dae Seog
DS
Bang
Yung-Jue
YJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D014057:Tomography, X-Ray Computed / Q000379:methods
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18