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Comparative Study
. 2012;17(9):1146-54.
doi: 10.1634/theoncologist.2011-0449. Epub 2012 Jun 18.

A prospective comparison of 18F-FDG PET/CT and CT as diagnostic tools to identify the primary tumor site in patients with extracervical carcinoma of unknown primary site

Anne Kirstine H Møller  1 , Annika Loft, Anne K Berthelsen, Karen D Pedersen, Jesper Graff, Charlotte B Christensen, Junia C Costa, Lene T Skovgaard, Katharina Perell, Bodil L Petersen, Gedske Daugaard
Affiliations
Comparative Study

A prospective comparison of 18F-FDG PET/CT and CT as diagnostic tools to identify the primary tumor site in patients with extracervical carcinoma of unknown primary site

Anne Kirstine H Møller et al. Oncologist. 2012.

Abstract

Background: The aim of the present study was to evaluate prospectively the diagnostic value of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) and conventional CT regarding the ability to detect the primary tumor site in patients with extracervical metastases from carcinoma of unknown primary (CUP) site.

Patients and methods: From January 2006 to December 2010, 136 newly diagnosed CUP patients with extracervical metastases underwent (18)F-FDG PET/CT. A standard of reference (SR) was established by a multidisciplinary team to ensure that the same set of criteria were used for classification of patients, that is, either as CUP patients or patients with a suggested primary tumor site. The independently obtained suggestions of primary tumor sites using PET/CT and CT were correlated with the SR to reach a consensus regarding true-positive (TP), true-negative, false-negative, and false-positive results.

Results: SR identified a primary tumor site in 66 CUP patients (48.9%). PET/CT identified 38 TP primary tumor sites and CT identified 43 TP primary tumor sites. No statistically significant differences were observed between (18)F-FDG PET/CT and CT alone in regard to sensitivity, specificity, and accuracy.

Conclusion: In the general CUP population with multiple extracervical metastases (18)F-FDG PET/CT does not represent a clear diagnostic advantage over CT alone regarding the ability to detect the primary tumor site.

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Conflict of interest statement

Disclosures: The authors indicated no financial relationships.

Section Editors: O.S. Hoekstra: Philips (RF); Malik Juweid: None

Reviewers “A” and “B”: None

Figures

Figure 1.
Figure 1.
Consort diagram. Abbreviations: CT, computed tomography; CUP, carcinoma of unknown primary; 18F-FDG PET/CT, 18F-fluorodeoxyglucose positron emission tomography/computed tomography.
Figure 2.
Figure 2.
A 59-year-old man with squamous cell carcinoma in inguinal lymph nodes. The primary tumor site in the urethra was only visible on the combined positron emission tomography/computed tomography scan but not with computed tomography alone.
Figure 3.
Figure 3.
A 51-year-old woman with adenocarcinoma of the peritoneal cavity. The histopathological suggestion of the primary tumor site was the lower gastrointestinal tract. The primary tumor site in the small intestine was only visible with computed tomography alone. On the combined positron emission tomography/computed tomography scan, the primary tumor site was misinterpreted as peritoneal carcinomatosis.
Figure 4.
Figure 4.
A 61-year-old man with adenocarcinoma in multiple organs (lung, liver, bone, lymph nodes). The histopathological suggestion of the primary tumor site was the lower gastrointestinal tract. The primary tumor was not identified with either positron emission tomography/computed tomography or computed tomography alone.
See this image and copyright information in PMC

References

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