Role of radio – iodine ablation according to risk stratification in well differentiated thyroid cancer

Abstract EN

The current study includes prospective analysis of 70 patients with well differentiated thyroid cancer to evaluate the role of I131 ablation therapy according to risk stratification.

The latter includes age, pathological type, histopathological criteria (tumor size-Capsular and vascular invasion-lymph nodal involvement).

According to these criteria patient population was divided into low risk group (30 patients) and high risk group (40 patients).

The former group received 30 mCi, while high risk group received 80 mci.

I 131 therapies was repeated every 6 months till achievement of complete ablation or for maximum of 4 doses.

Fifty five patients had complete response, while 15 patients had incomplete ablation.

The mean dose which produces total ablation in low dose therapy was 93.9 mCi versus 158.2 mCi in high dose therapy group.

There was higher response rate in the low risk group compared to the high risk group, yet, the difference is not statistically significant.

Higher incidence of incomplete ablation was found in patients with follicular carcinoma, positive capsular and vascular invasion and regional lymph nodal involvement.

Also, patients who had done hemi thyroidectomy had higher incidence of partial response compared to those who had near total thyroidectomy ± block neck dissection.

Tc99m MIBI scan in addition to estimation of serum thyroglobulin (Tg) level were useful in post ablation Group for assessment of residual, recurrent or metastatic disease.

In conclusion : In patients with well differentiated thyroid cancer, Low dose ablation therapy had better response in low risk group compared to high dose therapy in high risk group.

Also, serum Tg and Tc99m MIBI whole body scan (WBS) are greatly sensitive in follow up of patients after complete ablation for early detection of local recurrence or remote metastases.