Low-dose Radioactive I-131 Therapy after Total Thyroidectomy for Differentiated Thyroid Cancer

Korean Journal of Head & Neck Oncology 1998;14(2):214-219.
Published online November 30, 1998.

Chung Jin Choi;Sung Hoo Jung

갑상선 분화암 수술 후 저용량 방사성 옥소(I-131)요법

최정진;정성후

Abstract

Objectives: To assess the effectiveness of the low-dose(30mCi) I-131 ablation therapy for remnant thyroid tissue following total thyroidectomy for differentiated thyroid cancer.
Methods
Between March 1995 and December 1997, forty-eight patients were given ablative doses(30mCi) of I-131 after total thyroidectomy for differentiated thyroid cancer in the presence of I-131 uptake in remnant thyroid tissue. Effective ablation of remnant thyroid tissue was determined by following I-131 whole body scan. if remnant thyroid tissue remained, we repeated the same management at 6 months interval.
Results
Thirty-eight(79.1%) patients had papillary, 8(16.7%) follicular, 1(2.1%) medullary and 1(2.1%) Hurthle cell type cancer. Forty-eight patients underwent total thyroidectomy, among those central neck dissection was performed in 35 cases, and modified radical neck dissection in 14 cases. Postoperative complication developed in 8 cases, which included 4 cases of transient hypoparathyroidism, 1 case of permanent hypoparathyroidism, 2 cases of transient recurrent laryngeal nerve palsy, and 1 case of wound hematoma. There were significant remnant thyroid tissue in 46 cases(95.8%) of patients after total thyroidectomy, which could be ablated by low dose(30mCi) I-131. There were no statistical difference between operative procedures and number of treatment of I-131.
Conclusions
These results suggested that repeated low-dose(30mCi) I-131 therapy would be needed, therefore, high -dose I-131 therapy could be considered as ablation therapy for the remnant thyroid tissue after total thyroidectomy for differentiated thyroid cancer.

Key Words: Differentiated thyroid cancer, Total thyroidectomy, Low-dose I-131 therapy