Operative strategy for follicular thyroid cancer in risk groups stratified by pTNM staging

This study determined cancer survival rates and follow-up status at different pTNM stages to stratify risk groups in follicular thyroid carcinoma. Two hundred and fourteen follicular thyroid cancer patients (167 females, 47 males) who underwent surgery and followed-up treatment at a single medical center were enrolled in this retrospective study. Tumors were staged by UICC-TNM criteria (6th edition). Low risk for follicular thyroid cancer was defined as pT1N0M0. (Moderate-risk group) was defined as all other patients in pTNM stage I, and high risk as patients in stages II-IV. After mean follow-up of 9.6+/-0.3 years, 1.6% (2/120), 21.9% (7/32), 5.6% (1/18) and 52.3% (23/44) of patients in pTNM stages I-IV, respectively, died of thyroid cancer. Of 214 follicular thyroid cancer patients, 35 (16.4%), 85 (39.7%) and 94 (43.9%) were defined as low-, moderate- and high-risk groups at the time of surgery. None of the low-risk patients died, and all achieved disease-free status. In the moderate- and high-risk groups, 2.4% (2/85) and 27.7% (26/94) died of thyroid cancer. The moderate- and high-risk groups underwent near-total thyroidectomy and (131)I therapies, and 15 of 107 (14.9%) died of thyroid cancer while 18 (16.8%) had persistent disease at the end of the study period. Multiple regression analysis demonstrated that tumor size, radioactive iodide therapy and post-operative thyroglobulin level significantly differ between the mortality and survival groups. In conclusion, the low-risk follicular thyroid cancer group as defined by pTNM staging had excellent prognosis. Total thyroidectomy and post-operative radioactive iodide therapy are mandatory in moderate- and high-risk groups. Over one-fourth of the follicular thyroid cancer patients in the high-risk group died of thyroid cancer despite aggressive treatment.