Locally invasive, well-differentiated thyroid cancer. 22 years' experience at Memorial Sloan-Kettering Cancer Center.

Our experience with 32 cases of locally invasive well-differentiated thyroid carcinoma suggests the following: (1) Thyroidectomy may be limited to the area of gross tumor involvement with little risk of recurrence in the normal opposite lobe. (2) Elective neck dissection should be considered in patients with locally invasive tumors since the incidence of nodal metastases is high. As observed in this study, occult metastases were present in five of six patients dissected electively, and nodal metastases developed later in four of eight patients observed. (3) Surgical procedures for the primary tumor should remove all gross disease. This is possible with conservative operations in most patients; the only deaths from uncontrolled local disease occurred in two patients in whom gross disease was left at the first procedure. Most deaths were caused by distant metastases, and the 5, 10 and 15 year survival rates were 86, 64 and 64 percent, respectively.