Endocrine Abstracts

Objective: To know the pronostic value of serum thyroglobuline (Tg), obtained before thyroid ablation with I¹³¹, in order to predict cancer recurrence risk in patients treated with total thyroidectomy due to differentiated thyroid carcinoma (DTC).

Methods: We conducted a computed search of the published literature in Medline. We included diagnostic test studies that evaluated the relationship between Tg before I¹³¹ ablation, with local or distance tumoral recurrence. Selection criteria were Tg measurement method description and the explicit exclusion of patients with positive thyroglobuline antibodies. To express the accumulate diagnostic test pronostic value, we applied likelihood ratio (LR). To obtain accumulate likelihood ratio we introduced our data in the Revman 4.2 program (Cochrane Initiative) and selected the accumulated OR function. Statistical heterogeneity across the studies was tested with the use of Cochrane Q statistic and Higgins’s I² coefficient in a randon effect model.

Results: The mean recurrence rate was 20.39%. Next table shows accumulate LR by Tg value ranges:

Conclusions: The best range of values of Tg before I131 ablation in order to predict recurrence in DTC’s thyroidectomized patients is 27.5–30.25 ng/ml.

For a recurrence rate of 20.39% the positive predictive value of Tg before ablation is 91% and the negative predictive value 0.76%.