Thyroid carcinoma with bone metastases: a prognostic factor study

Abstract

Objective: Occult clinical presentations usually hinder the early detection and management of patients with bone metastases from thyroid carcinoma. We retrospectively investigated the clinical outcomes of such patients from 1993 to 2004 and analyzed the prognostic parameters.

Design: The basic demographic data and manifestations of 44 patients who had thyroid carcinoma with bone metastases were reviewed. We studied the gender, age, locations of metastases, histological types, treatment methods, hypercalcemic episodes and results of treatments. We used Kaplan-Meier survival analysis and log-rank tests to access the statistical significance.

Main outcome: The incidence of bone metastasis from thyroid carcinomas in this series was 5.0%. Twenty patients (45.4%) had follicular, 16 (36.3%) had papillary, 3 (6.8%) had anaplastic, 3 (6.8%) had medullary, and 2 (4.5%) had Hurthel cell carcinomas. Twelve patients had hypercalcemic episodes, ranging from 2.6 to 2.9 mmolL(-1) (mean ± SD: 2.68 ± 0.15 mmolL(-1)). Survival time after bone metastases ranged from 2 months to 8 years (mean ± SD: 5.3 ± 1.3 years). The 5-year survival rate was 79.4% and the 10-year survival rate was 52.9%. Regarding the histological cancer type, patients with papillary and follicular cancers survived significantly longer than those with anaplastic and medullary cancers (p < 0.05). In addition, the patients presenting with hypercalcemia had the worst survival (p < 0.05).

Conclusions: Thyroid carcinoma can present with bone metastases in its early stage. We found that both tumor type and hypercalcemia were significant prognostic factors for survival time.

Keywords: bone; carcinoma; metastasis; prognosis; thyroid.

Figure 1

Survivor-ship curve as determined by Kaplan-Meier method, the 5-year survival rate was 79.4%, the 10-year survival rate was 52.9%.

Figure 2

Kaplan – Meier plot of surviving after diagnosis of bone metastasis. The results showed that both tumor type and hypercalcemia were the significant prognostic factors (p < 0.05). (A) The 5-year survival rate was 64.2% for papillary cancer, 82.0% for follicular cancer, 0% for anaplastic cancer, 100% for Hurthel cell cancer and 61.1% for medullary cancer. (B) The 5-year survival rate for single bone metastasis was 81.2% and 80.4% for multiple bone metastases. (C) The 5-year survival rate 80.2% when treated with surgical method and 70.6% when treated without surgical method. (D) The 5-year survival rate for patients who have no hypercalcemia episode noted during the course of treatment was 84.0% and only 55.0% when more than one episode of hypercalcemia was noted. (p < 0.05) (E) The 5-year survival rate was 83.1% for female and 64.6% for male.