Prophylactic completion thyroidectomy for differentiated thyroid carcinoma: Prediction of extrathyroidal soft tissue infiltrates

Controversy exists on the extent of completion surgery for differentiated t hyroid carcinoma (DTC). Between November 1994 and October 1999, 88 consecut ive DTC patients who had no evidence of residual, tumor after primary surge ry underwent completion total thyroidectomy in conjunction with a systemati c en bloc resection of the cervicocentral lymph node compartment. To identi fy individual parameters predictive of occult residual tumor, three separat e logistic regression analyses were fitted for intrathyroidal tumor, extrat hyroidal soft tissue infiltrate and cervicocentral nodal metastasis. Altoge ther, occult residual tumor was found in 22% (19/88) of patients. Occult in trathyroidal tumor, extrathyroidal soft tissue infiltrate, and cervicocentr al nodal metastasis were encountered in 11% (10/88), 6% (5/88), and 10% (9/ 88), respectively. On logistic regression analysis, patients with multifoca l DTC on primary surgery had a 17.4 times higher risk (p = 0.026) on reoper ation to harbor extrathyroidal soft tissue infiltrates within the cervicoce ntral compartment. At least in multifocal DTC, a systematic en bloc resecti on of the thyroid remnant and cervicocentral lymph node compartment is warr anted to ensure clearance of occult extrathyroidal soft tissue infiltrates, setting the stage for radioiodine therapy. Selective lymph node dissection alone does not seem capable of eliminating these soft tissue infiltrates f rom the cervicocentral compartment.