Importance of surgical procedure in radioactive iodine ablation of differentiated carcinoma of thyroid

Objective: To evaluate surgical procedure best suited for postoperative radio-ablation. Design: A prospective study. Place and duration of Study: Study was conducted at Punjab Institute of Nuclear Medicine, Faisalabad, in collaboration with surgery and radiotherapy departments of allied Hospital from January, 1997 to December, 2000. Subject and Methods: Eighty patients,32 males and 48 females) (papillary =68, follicular = 12) from 14-60 years of age (mean age = 36.45 years). Were included in the study. The dose of I-131 was kept fixed (125-150 mCi). Response of I-131 was studied in three groups based on the surgical procedure. Group 1 comprised of 36 patients undergoing near-total/total thyroidectomy. Group II included 36 patients with lobectomy/subtotal thyroidectomy. Group III contained 8 patients with de-bulking surgery. Results: In group I, 77.7% patients showed ablation of residual thyroid tissue after single dose of radioiodine and 22.2% required second dose after six months. In group II, 33.3% showed complete ablation after single dose and the rest needed the second dose. Poor response was observed in third group where ablation was not achieved even after two doses and all patients showed radiation thyroiditis and respiratory discomfort. Conclusion: Near-total/total thyroidectomy adopted for differentiated carcinoma of thyroid is better surgical procedure than lobectomy/subtotal thyroidectomy if the patient requires postoperative I-131 ablation. De-bulking surgery gives poor results if combined with postoperative radioiodine ablation. (author)