title: Stimulated high serum thyroglobulin with negative whole body imaging do not warrant an aggressive diagnostic and therapeutic approach in differentiated thyroid cancer patients: A follow-up of 5 years or till recurrence.
abstract: OBJECTIVE
  To study the clinical significance of stimulated high serum thyroglobulin (sTg) and of normal whole body imaging (WBI) in differentiated thyroid cancer (DTC) patients during their first follow-up and in a 5 years follow-up or till recurrence.
  
  
  METHODS
  Sixty four DTC patients were retrospectively studied and were divided into two groups. Group 1, of 35 patients with disease free status on their first follow-up and group 2, of 29 patients with high sTg (>2 μg/mL), but with normal WBI, iodine-131 (¹³¹I) findings. Patients were categorized into low, intermediate and high risk patients based on the ¹³¹I WBS findings. Histology, stage and risk-categories of both groups were statistically correlated. Best sTg cut-off for predicting recurrence was generated by receiver operating characteristic (ROC). Odd ratio for sTg trend was also analyzed for risk of recurrence in group 2. Independent t test was used for progression free survival (PFS) comparison of the two groups.
  
  
  RESULTS
  No statistical differences were seen in histology, stage and risk category distributions between the groups. Group 2 patients with high sTg (range 2.5-81 μg/L, mean 20.5 μg/L) on their first follow-up had higher risk of recurrence (odd ratio 4.304) but P value was insignificant (P:0.090). Eighty six per cent of group 2 patients showed decreasing trends and in 62% of group 2 patients, high serum sTg fell to normal. Indeed, decreasing trends of sTg reduced the risk of recurrence (odd ratio 1.3939, P:0.79). Analysis by ROC showed that sTg>11 μg/L was the best cut-off in predicting recurrence with sensitivity 100% and specificity 56%. High sTg was not associated with low PFS, (P:0.232), however patients with increasing sTg had significantly shorter PFS (P<0.005).
  
  
  CONCLUSIONS
  High sTg with negative ¹³¹I WBS did not warrant an aggressive DTC disease. These patients in their 5 years or till recurrence follow-up showed downward trends of serum sTg, no higher risk or recurrence and no shorter PFS.
authors.affiliation: Department of Nuclear Medicine, Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, India. docmanojgupta@yahoo.com.
authors.forename: Manoj
authors.initials: M
authors.lastname: Gupta
authors.forename: Partha S
authors.initials: PS
authors.lastname: Choudhury
authors.forename: Sudipta
authors.initials: S
authors.lastname: Nag
authors.forename: Parul
authors.initials: P
authors.lastname: Gupta
mesh_terms: D015415:Biomarkers / Q000097:blood; D000066491:Clinical Decision-Making / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods; D018579:Patient Selection; D049268:Positron-Emission Tomography / Q000379:methods*; D012008:Recurrence; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000628:therapy*; D051598:Whole Body Imaging
chemical_list: D015415:Biomarkers; D013954:Thyroglobulin