Charles Marcus MBBS, Presenter: Nothing to Disclose

Antoniou Alexander MD, Abstract Co-Author: Nothing to Disclose

Rathan M. Subramaniam MD, PhD, Abstract Co-Author: Speakers Bureau, Eli Lilly and Company

To evaluate the added value of follow-up and surveillance PET/CT to clinical assessment and survival outcome in thyroid cancer patients. 

This is a retrospective study of 258 biopsy proven thyroid cancer patients at a single tertiary center. A total of 349 follow up PET/CT scans done 6 or more months from initial treatment completion were included in this study. Median follow up from completion of primary treatment was 52.3 months (range, 6.0 – 705.0 months). Overall survival benefit was measured using Kaplan-Meier plots with a Mantel-Cox log-rank test. Multivariate Cox regression model is provided with clinical covariates. 

Of the 349 PET/CT scans, 129 were positive and 220 were negative for recurrence. A subgroup analysis demonstrated a difference in overall survival (OS) in 166 scans completed between 6-48 months (p= 0.034), but did not demonstrate a difference in 183 scans completed after 48 months (p=0.5086) between the positive and negative cohorts. PET/CT identified recurrence in 12.6% (14/111) of scans without prior clinical suspicion and ruled out recurrence in 37.0% (88/238) of scans with prior clinical suspicion. There was significant difference in OS when grouped by clinical suspicion (p=0.0010). In a multivariate Cox regression model, factors associated with overall survival were age (p=0.0005), gender (p=0.0187), histology (p=0.0487), clinical suspicion (p=0.0004) and PET/CT result (p=0.0144). An age stratified subgroup analysis demonstrated significant difference in OS by PET scan result among patients between 40 and 65 years old, but not in those younger than 40 years or older than 65 years (p=0.0130, p=0.6694, and p=0.2706 respectively). 

FDG PET/CT performed in follow-up more than 6 months from primary treatment completion adds value to clinical judgment and is a prognostic marker of overall survival in thyroid cancer patients.

Follow-up PET/CT study perfomed after 6 months of treatment completion can add value to clinical judgement and provides prognostic information in thyroid cancer patients.

Marcus, C, Alexander, A, Subramaniam, R, Patient Survival Outcome and Follow Up/Surveillance 18F FDG PET/CT in Thyroid Cancer.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14017984.html