Second operations for completion of thyroidectomy in treatment of differentiated thyroid cancer. Discussion

: The role of elective completion thyroidectomy after lobectomy for differentiated thyroid cancers remains controversial. The potential benefit of tumor removal by the second procedure is considered by some to be overbalanced by a prohibitive operative morbidity rate. During a 20-year period at the University of Chicago Medical Center, 26 patients underwent completion thyroidectomy within a 6-month period of the original thyroid operation. This group represents 8% of the 326 patients who underwent surgery during that time for differentiated thyroid cancer (269 papillary and 57 follicular). Of the 26 patients, 18 had papillary and eight had follicular cancers. The average size was 2.5 cm, with 24 of 26 being greater than 1 cm in diameter. At the first operation, 81% of tumors were intrathyroidal. Eight percent had lymph node metastases and 12% manifested local invasion. Tumor was found in eight (31%) of 26 of the reoperative specimens. The incidence of tumor did not vary by histologic type but did differ according to the extent of the original operation. Cancer was found in 50% (three of six) of those who had undergone previous partial lobectomy, in 33% (five of 15) of those after a total lobectomy, and in none of five who had undergone a prior bilateral (although incomplete) thyroid resection. One permanent recurrent nerve injury occurred at the first operation. No additional recurrent nerve injuries or hypoparathyroidism occurred as a result of the second operation. Finally, no disease characteristic of the initial tumor (e.g., size, clinical class, tumor capsular invasion, multifocality, thyroiditis, or extrathyroidal tumor invasiveness) predicted the presence or absence of tumor on the second side. We conclude that completion thyroidectomy is appropriate for patients with lesions 1 cm or greater who have undergone lobectomy or less at the original operation, because 40% of such patients would be expected to have residual cancer. With care, this operation can be performed with minimal morbidity.