Prognostic Factors and Treatment in Follicular Thyroid Carcinoma

ABSTRACT

PURPOSE: Follicular thyroid carcinoma (FTC) and papillary thyroid carcinoma (PTC) are two main subtypes of well-differentiated thyroid cancer. Sometimes FTCs present more aggressive features such as vascular invasion. The object of this study was to investigate the clinicopathologic features, prognostic factors and treatment outcome of FTC. METHODS: This retrospective study enrolled 91 patients diagnosed with FTC between November 1994 and October 2008. The clinicopathologic characteristics, treatment outcome and follow up data were analyzed. RESULTS: The median follow-up (f/u) period was 76.1 months. Distant metastases at the time of diagnosis were detected in 12 patients. During the f/u period, one local recurrence and 4 distant metastases developed. Local recurrence or distant metastasis were noticed in 12 out of 19 patients with widely invasive type and 5 out of 36 patients with minimally invasive type with vascular invasion were also noted. The median times to local recurrence or distant metastasis were 59.0 and 34.2 months, respectively. On analysis, according to the clinocopathologic factors, presence of vascular invasion, extrathyroidal extension, invasion to structure, incomplete excision and pathological classification were independent prognostic factors for recurrence or distant metastasis. Disease specific mortality was seen in one patient. CONCLUSION: This study shows that aggressive treatments such as total thyroidectomy followed by radioiodine therapy and close follow-up of patients with minimally invasive type with vascular invasion and widely invasive type of FTC should be considered due to the chance of local recurrence and distant metastasis.