Diagnostic accuracy of 18F-FDG PET in restaging patients with medullary thyroid carcinoma and elevated calcitonin levels Journal Article

Authors: Ong, S. C.; Schoder, H.; Patel, S. G.; Tabangay Lim, I. M.; Doddamane, I.; Gonen, M.; Shaha, A. R.; Tuttle, R. M.; Shah, J. P.; Larson, S. M.
Article Title: Diagnostic accuracy of 18F-FDG PET in restaging patients with medullary thyroid carcinoma and elevated calcitonin levels
Abstract: Medullary thyroid carcinoma (MTC) is a rare endocrine tumor arising from the C-cells of the thyroid gland. Calcitonin is the principal serum tumor marker. A rising calcitonin level after total thyroidectomy for localized disease generally indicates residual, recurrent, or metastatic disease. The role of 18F-FDG PET in MTC remains somewhat unclear. We reviewed our own experience with 18F-FDG PET in postthyroidectomy MTC patients with elevated calcitonin. Methods: From our database, we identified patients with suspected residual, recurrent, or metastatic MTC and elevated calcitonin who had been referred for 18F-FDG PET between January 2000 and October 2005. 18F-FDG PET findings were classified as positive or negative on the basis of visual interpretation of the scan. Standardized uptake values (SUVs) were also calculated. The 18F-FDG PET findings were verified by histopathologic examination, when available, or other imaging studies and clinical follow-up. Any negative 18F-FDG PET result was considered false-negative. Results: Twenty-eight patients underwent a total of 38 18F-FDG PET studies. Calcitonin levels ranged from 106 to 541,000 pg/mL (median, 7,260 pg/mL). There were 23 true-positive, 1 false-positive, and 14 false-negative 18F-FDG PET scans, yielding an overall sensitivity of 62%. There was no true-positive finding when calcitonin levels were below 509 pg/mL (n = 5). Using an arbitrary cutoff of 1,000 pg/mL, we found that the sensitivity in scans with calcitonin levels greater than 1,000 pg/mL increased to 78% (21/27; 95% confidence interval, 58%-91%). The mean SUV of all lesions with 18F-FDG uptake was 5.3 ± 3.2 (range, 2.0-15.9). Among the 14 patients with false-negative 18F-FDG PET findings, 8 had concurrent anatomic imaging studies and only 2 of these had positive findings. Conclusion: 18F-FDG PET can detect residual, recurrent, or metastatic MTC with a reasonable sensitivity of 78% when the calcitonin level is above 1,000 pg/mL but appears of limited use if the calcitonin level is below 500 pg/mL. Copyright © 2007 by the Society of Nuclear Medicine, Inc.
Keywords: cancer survival; aged; middle aged; histopathology; cancer recurrence; cancer staging; positron emission tomography; methodology; cancer diagnosis; neoplasm staging; diagnostic accuracy; laboratory diagnosis; sensitivity and specificity; metabolism; metastasis; tumor markers, biological; calcitonin; tumor marker; biosynthesis; fluorodeoxyglucose f 18; fluorodeoxyglucose f18; neoplasm metastasis; thyroidectomy; thyroid neoplasms; image processing, computer-assisted; image processing; false positive reactions; radiodiagnosis; thyroid tumor; medullary carcinoma; carcinoma, medullary; thyroid medullary carcinoma; medullary thyroid cancer; 18f-fdg pet
Journal Title: Journal of Nuclear Medicine
Volume: 48
Issue: 4
ISSN: 0161-5505
Publisher: Society of Nuclear Medicine  
Date Published: 2007-04-01
Start Page: 501
End Page: 507
Language: English
DOI: 10.2967/jnumed.106.036681
PUBMED: 17401085
PROVIDER: scopus
Notes: --- - "Cited By (since 1996): 41" - "Export Date: 17 November 2011" - "CODEN: JNMEA" - "Source: Scopus"
Citation Impact
MSK Authors
  1. Ida Marie Tabangay Lim
    1 Lim
  2. Seng Chuan Ong
    3 Ong
  3. Ashok R Shaha
    633 Shaha
  4. Snehal G Patel
    365 Patel
  5. Mithat Gonen
    885 Gonen
  6. Robert M Tuttle
    439 Tuttle
  7. Heiko Schoder
    419 Schoder
  8. Steven M Larson
    918 Larson
  9. Jatin P Shah
    670 Shah