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A comparison of positron emission tomography and colonoscopy for the detection of advanced colorectal neoplasms in subjects undergoing a health check-up.

Huang SW, Hsu CM, Jeng WJ, Yen TC, Su MY, Chiu CT - PLoS ONE (2013)

Bottom Line: The results of colonoscopy were taken as the gold standard, either with or without the results of the histopathological examination.An advanced neoplasm was defined as the presence of a malignant tumor, an adenoma ≥1 cm, or histological evidence of high-grade dysplasia or significant villous components.We conclude that FDG PET/CT screening of advanced colorectal neoplasms is unwarranted, especially in the presence of lesions with an endoscopic size ≤1.5 cm or low-grade dysplasia.

View Article: PubMed Central - PubMed

Affiliation: Department of Gastroenterology and Hepatology, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.

ABSTRACT

Background & aims: There is no agreement as to whether F-18 fluorodeoxyglucose positron emission tomography and computed tomography (FDG PET/CT) screening for advanced colorectal neoplasms is meaningful. This retrospective study was undertaken to determine whether FDG PET/CT may be a valuable screening tool for the detection of advanced colorectal neoplasms.

Methods: A retrospective review of the records of 1,109 FDG PET/CT scans acquired from January 2007 to December 2011 was performed. Colonoscopy and FDG PET/CT imaging were performed within two days of each other. The results of colonoscopy were taken as the gold standard, either with or without the results of the histopathological examination. An advanced neoplasm was defined as the presence of a malignant tumor, an adenoma ≥1 cm, or histological evidence of high-grade dysplasia or significant villous components.

Results: A total of 36 subjects had advanced colorectal neoplasms detected by colonoscopy (totaling 38 neoplasms). Six of the 38 neoplasms were also detected by FDG PET/CT. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of FDG PET/CT in the detection of advanced colorectal neoplasms were 15.8% (6/38), 99.1% (1063/1073), 37.5% (6/16), 97.1% (1063/1095), and 96.2% (1069/1111) respectively. The presence of lesions with an endoscopic size ≤1.5 cm (P<0.001) and low-grade dysplasia (P<0.001) were the main predictors of false-negative FDG PET/CT findings.

Conclusions: We conclude that FDG PET/CT screening of advanced colorectal neoplasms is unwarranted, especially in the presence of lesions with an endoscopic size ≤1.5 cm or low-grade dysplasia.

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Related in: MedlinePlus

Representative cases of false-negative (panel A) and false-positive (panel B) FDG PET/CT findings.(A) One polypoid cancer (1.5 cm in size) was identified by colonoscopy in the sigmoid colon. FDG PET/CT scans revealed an increased FDG uptake in the luminal air (arrowhead). This result was erroneously interpreted as a negative finding because of misregistration. (B) Colonoscopy revealed a normal mucosa. However, FDG PET/CT showed an increased FDG uptake in the sigmoid colon (arrow), which was erroneously interpreted as a positive result.
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pone-0069111-g002: Representative cases of false-negative (panel A) and false-positive (panel B) FDG PET/CT findings.(A) One polypoid cancer (1.5 cm in size) was identified by colonoscopy in the sigmoid colon. FDG PET/CT scans revealed an increased FDG uptake in the luminal air (arrowhead). This result was erroneously interpreted as a negative finding because of misregistration. (B) Colonoscopy revealed a normal mucosa. However, FDG PET/CT showed an increased FDG uptake in the sigmoid colon (arrow), which was erroneously interpreted as a positive result.

Mentions: The factors unfavorably associated with the likelihood of true-positive FDG PET/CT findings included tumor size (≤1.5 cm vs. >1.5 cm, 3.3% vs. 71.4%, P<0.001) and the degree of dysplasia (low grade vs. high grade/adenocarcinoma, 0% vs. 71.4%, P<0.001) (Table 3). The median SUVmax values of the participants with true-positive and false-positive FDG PET/CT findings were 8.6 and 5.6, respectively (P = 0.057). The median SUVmax values of subjects with adenocarcinomas and non-malignant advanced adenomas were 25.0 and 6.7, respectively (P = 0.05). The overall rate of positive FDG PET/CT results was 1.4% (16/1111). Eleven of the 16 subjects (68.8%) who had positive FDG PET/CT results also showed positive findings on colonoscopy. Figure 1 shows a representative case with true-positive FDG PET/CT results, whereas Figure 2 shows two representative cases with false-negative (panel A) and false-positive (panel B) FDG PET/CT findings. The detailed characteristics of subjects with true-positive, false-positive, and false-negative FDG PET/CT findings are reported in Table S1.


A comparison of positron emission tomography and colonoscopy for the detection of advanced colorectal neoplasms in subjects undergoing a health check-up.

Huang SW, Hsu CM, Jeng WJ, Yen TC, Su MY, Chiu CT - PLoS ONE (2013)

Representative cases of false-negative (panel A) and false-positive (panel B) FDG PET/CT findings.(A) One polypoid cancer (1.5 cm in size) was identified by colonoscopy in the sigmoid colon. FDG PET/CT scans revealed an increased FDG uptake in the luminal air (arrowhead). This result was erroneously interpreted as a negative finding because of misregistration. (B) Colonoscopy revealed a normal mucosa. However, FDG PET/CT showed an increased FDG uptake in the sigmoid colon (arrow), which was erroneously interpreted as a positive result.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3716810&req=5

pone-0069111-g002: Representative cases of false-negative (panel A) and false-positive (panel B) FDG PET/CT findings.(A) One polypoid cancer (1.5 cm in size) was identified by colonoscopy in the sigmoid colon. FDG PET/CT scans revealed an increased FDG uptake in the luminal air (arrowhead). This result was erroneously interpreted as a negative finding because of misregistration. (B) Colonoscopy revealed a normal mucosa. However, FDG PET/CT showed an increased FDG uptake in the sigmoid colon (arrow), which was erroneously interpreted as a positive result.
Mentions: The factors unfavorably associated with the likelihood of true-positive FDG PET/CT findings included tumor size (≤1.5 cm vs. >1.5 cm, 3.3% vs. 71.4%, P<0.001) and the degree of dysplasia (low grade vs. high grade/adenocarcinoma, 0% vs. 71.4%, P<0.001) (Table 3). The median SUVmax values of the participants with true-positive and false-positive FDG PET/CT findings were 8.6 and 5.6, respectively (P = 0.057). The median SUVmax values of subjects with adenocarcinomas and non-malignant advanced adenomas were 25.0 and 6.7, respectively (P = 0.05). The overall rate of positive FDG PET/CT results was 1.4% (16/1111). Eleven of the 16 subjects (68.8%) who had positive FDG PET/CT results also showed positive findings on colonoscopy. Figure 1 shows a representative case with true-positive FDG PET/CT results, whereas Figure 2 shows two representative cases with false-negative (panel A) and false-positive (panel B) FDG PET/CT findings. The detailed characteristics of subjects with true-positive, false-positive, and false-negative FDG PET/CT findings are reported in Table S1.

Bottom Line: The results of colonoscopy were taken as the gold standard, either with or without the results of the histopathological examination.An advanced neoplasm was defined as the presence of a malignant tumor, an adenoma ≥1 cm, or histological evidence of high-grade dysplasia or significant villous components.We conclude that FDG PET/CT screening of advanced colorectal neoplasms is unwarranted, especially in the presence of lesions with an endoscopic size ≤1.5 cm or low-grade dysplasia.

View Article: PubMed Central - PubMed

Affiliation: Department of Gastroenterology and Hepatology, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.

ABSTRACT

Background & aims: There is no agreement as to whether F-18 fluorodeoxyglucose positron emission tomography and computed tomography (FDG PET/CT) screening for advanced colorectal neoplasms is meaningful. This retrospective study was undertaken to determine whether FDG PET/CT may be a valuable screening tool for the detection of advanced colorectal neoplasms.

Methods: A retrospective review of the records of 1,109 FDG PET/CT scans acquired from January 2007 to December 2011 was performed. Colonoscopy and FDG PET/CT imaging were performed within two days of each other. The results of colonoscopy were taken as the gold standard, either with or without the results of the histopathological examination. An advanced neoplasm was defined as the presence of a malignant tumor, an adenoma ≥1 cm, or histological evidence of high-grade dysplasia or significant villous components.

Results: A total of 36 subjects had advanced colorectal neoplasms detected by colonoscopy (totaling 38 neoplasms). Six of the 38 neoplasms were also detected by FDG PET/CT. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of FDG PET/CT in the detection of advanced colorectal neoplasms were 15.8% (6/38), 99.1% (1063/1073), 37.5% (6/16), 97.1% (1063/1095), and 96.2% (1069/1111) respectively. The presence of lesions with an endoscopic size ≤1.5 cm (P<0.001) and low-grade dysplasia (P<0.001) were the main predictors of false-negative FDG PET/CT findings.

Conclusions: We conclude that FDG PET/CT screening of advanced colorectal neoplasms is unwarranted, especially in the presence of lesions with an endoscopic size ≤1.5 cm or low-grade dysplasia.

Show MeSH
Related in: MedlinePlus