Follicular thyroid carcinoma: prognostic factors and the role of radioiodine.
BACKGROUND
The objective of this study was to investigate the patterns of recurrence, various prognostic factors, and the role of radioiodine in the treatment of patients with follicular thyroid carcinoma (FTC).


METHODS
The clinical outcomes of 215 patients with FTC who were treated at a single institution were analyzed retrospectively. The mean follow-up was 10.8 years.


RESULTS
The actuarial rates of cause specific survival (CSS), locoregional (LR) control, and freedom from distant metastasis (DM) at 10 years were 81%, 83%, and 72.3%, respectively. The independent prognostic factors for survival were metastasis at presentation (relative risk [RR], 47.7), radioiodine (RAI) treatment (RR, 0.25), extrathyroidal extension (RR, 3.8), and the postoperative absence of macroscopic disease in the neck region (RR, 0.06). In patients who were treated with RAI, both the LR failure rate (RR, 0.24) and the mortality rate (RR, 0.25) were reduced to about 25%. Subgroup analysis revealed that RAI improved the survival of patients with DM at presentation (RR, 0.17) and improved the LR control rate in patients who had no DM at presentation (RR, 0.13). For patients who underwent total thyroidectomy with negative resection margins, RAI significantly reduced the rate of LR recurrence (RR, 0.05). Patients with the minimally invasive type of FTC had a good prognosis. The 10-year rates for CSS, LR control, and freedom from DM were 97.6%, 100%, and 90.6%, respectively. The prognosis of patients with frankly invasive FTC was much poorer. The 10-year rates for CSS, LR control, and freedom from DM were 66.7%, 100%, and 45%, respectively.


CONCLUSIONS
RAI is an effective treatment for patients with FTC. It was associated with improved survival rates and fewer recurrences.
Chow
Sin-Ming
SM
Department of Clinical Oncology, Queen Elizabeth Hospital, Kowloon, Hong Kong, China.
Law
Stephen C K
SC
Mendenhall
William M
WM
Au
Siu-Kie
SK
Yau
Stephen
S
Yuen
Kam-Tong
KT
Law
Chi-Ching
CC
Lau
Wai-Hon
WH
D018263:Adenocarcinoma, Follicular / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016019:Survival Analysis; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D013965:Thyroidectomy; D016896:Treatment Outcome
D007457:Iodine Radioisotopes