Follicular Thyroid Cancer Treated at the Mayo Clinic, 1946 Through 1970: Initial Manifestations, Pathologic Findings, Therapy, and Outcome

Abstract

We retrospectively analyzed the outcome of all patients who received their primary treatment for follicular thyroid cancer at the Mayo Clinic between 1946 and 1970. The diagnosis was confirmed by reexamination of preserved tissue specimens. The 57 female and 43 male patients (mean age, 53 years) underwent follow-up for a maximum of 32 years (mean, 17.4 years). All patients were treated surgically, and total removal of primary tumor was thought to have been accomplished in all but three. Only 2 of the 88 patients without distant metastatic lesions at the time of initial diagnosis underwent ablation of the thyroid remnant. At the conclusion of the study, 52 patients had died, thyroid cancer being the cause of death in 19. On the basis of univariate survival analysis, age more than 50 years, tumor size that exceeded 3.9 cm, higher tumor grade, presence of marked vascular invasion, adjacent tissue invasion, and distant metastatic involvement at the time of initial diagnosis were associated with increased cancer mortality. Multivariate analysis (by Cox proportional hazards model), however, identified only age greater than 50 years, marked vascular invasion, and metastatic disease at the time of diagnosis to be independent predictors of follicular thyroid cancer-related mortality. Patients with two or more of these predictors were classified as being high risk. These patients had 5- and 20-year survival rates of 47% and 8%, respectively; the corresponding survival data for the low-risk group were 99% at 5 years and 86% at 20 years. The identification of these risk groups may facilitate a more rational approach to treatment of follicular thyroid cancer.

Prognostic factors for thyroid carcinoma

“…Tumor differentiation status was consistent with the results of other series. 9,34 The majority of cases diagnosed from 1973 to 1983 fell into was not reported for the majority of patients, and selective or variable reporting may have biased the surthis low-risk category with 10-year relative survival greater than 0.98. Patients with regional-or distantvival estimates.…”

“…ICD-O ogy and stage. [9][10][11][12][13][14][15][16][17][18][19][20] However, the relative importance of each of these characteristics as prognostic factors and morphology codes were used to specify histologic types. 22 Papillary histology included codes 8050, 8260, whether findings in one population can be generalized to other populations is not known.…”

Prognostic factors of minimally invasive follicular thyroid carcinoma: Extensive vascular invasion significantly affects patient prognosis

“…Previous studies showed that widely invasive FTC displays a significantly poorer prognosis than minimally invasive FTC [4,5]. To date, other conventional prognostic factors of FTC such as distant metastasis at diagnosis (M1), old age, and large tumor size have also been identified [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. However, prognostic factors of minimally invasive FTC have not been intensively investigated and, to our knowledge, only one manuscript has been published for a large series of patients [23].…”

Are prognostic scoring systems of value in patients with follicular thyroid carcinoma?

“…Its lack of frequency has made it more difficult to study and often the results of papillary carcinoma have been extrapolated to follicular carcinoma (19,20,21). Very few studies have examined the risk factors affecting the prognosis of follicular carcinoma (19,20,21), and there is great variability between them. This could be a result of fewer patients in most studies, which means that small variations in the variables analyzed can lead to a prognostic factor being significant or not.…”