Prognostic value of postoperative and post-ablative serum thyroglobulin levels in patients with differentiated thyroid cancer.
BACKGROUND
The study was designed to examine the value of post-operative and post-ablative serum thyroglobulin levels and diagnostic whole body scan in predicting remission in patients with differentiated thyroid carcinoma.


METHODS
Serum TG levels and diagnostic iodine-123 whole body scans performed prior to and 6-12 months after 131I ablation for DTC were evaluated in 100 consecutive patients at King Faisal Specialist Hospital Riyadh. Patients were followed up for a period of 7.6 years (range 7-10 years). All patients underwent total thyroidectomypriorto 131I ablation.


RESULTS
Patients with serum TG levels < 8 ng/ml post thyroidectomy (50 patients) also maintained low TG < 8 ng/ml after 131I ablation and had better outcome (60%) remission. On the other hand DTC subjects with higher TG > 8 ng/ml post thyroidectomy (50 patients) 40% remained in remission X2 = 4.00, p = 0.046. For the group with initial high post-operative TG, it became < 8 ng/ml in 34/50 (68%) patients after ablation with 131I and in this subgroup, remission was seen in 16/34 (47%) of patients in contrast to 4/16 (25%) remission rate in those who continue to have TG > 8 ng/ml after ablation. At the end of follow up, 123I-WBS was positive in 4% and 10% of patients with initial TG < 8 ng/ml and TG > 8 ng/ml respectively; X2 = 1.38, p= 0.24.


CONCLUSIONS
Post-operative and post-ablative serum TG levels -but not follow up diagnostic WBS- have predictive values and permit selection of patients with higher risk for persistent/recurrent disease.
Raef
H
H
Department of Medicine, King Faisal Specialist Hospital & Research Center Riyadh, Saudi Arabia.
Malabu
U H
UH
Alfadhli
E
E
Al-Hajjaj
A
A
Al-Sobhi
S
S
Rifai
A
A
Al-Nuaim
A
A
D000328:Adult; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D011184:Postoperative Period; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D012074:Remission Induction; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000601:surgery*; D013965:Thyroidectomy; D013997:Time Factors
D007457:Iodine Radioisotopes; D013954:Thyroglobulin