Clinical Features of Bone Metastases Resulting from Thyroid Cancer: A Review of 28 Patients over a 20-year Period

Abstract

Abstract. Bone is the second most frequent site of metastasis resulting from thyroid cancer. Many studies have investigated clinical features and prognostic factors of distant metastases stemming from thyroid cancer in Western countries. The purpose of this study was to review clinical characteristics of Korean patients with bone metastasis originating from thyroid cancer. Between January 1985 and August 2004, 28 patients with thyroid cancer were diagnosed with bone metastases at the Yonsei Severance Hospital in Seoul, Korea. Their clinical characteristics were analyzed retrospectively. Incidence of bone metastasis from follicular thyroid cancer was 6.8% (9 of 132 patients), and 0.4% (13 of 3,154 patients) from papillary thyroid cancer, with an odds ratio of 17.67 (95% confidence interval; 7.41-42). Twelve patients had no symptoms of bone metastasis. Overall mean number of metastasis sites was 2.6 ± 1.9, and 12 patients had a solitary bone metastasis. Survival rates between the synchronous and metachronous metastasis groups were not significantly different, and the number of metastasis sites did not affect survival. However, the survival of patients that underwent curative treatment was longer than those with palliation (P = 0.0317). In Korea, the overall incidence of bone metastasis resulting from thyroid cancer was less than our expectation. Many patients were asymptomatic, and had a tendency of undergoing less aggressive or palliative treatment, even though the long-term survival of distant metastasis resulting from thyroid cancer with active treatment is relatively good. Further studies of the prognostic factors and effectiveness of various treatments of these patients are needed to enhance survival. DISTANT metastasis in thyroid cancer is well known and develops in 7% to 23% of patients with differentiated thyroid cancer [1]. In anaplastic thyroid cancer, 25% to 50% of patients may have synchronous pulmonary metastases at the time of diagnosis [2], while 20% of patients with sporadic medullary thyroid carcinoma had distant metastases at the time of diagnosis [3]. Bone is the second most common site of metastasis resulting from thyroid cancer after lung. The incidence of bone metastasis varies along with the degree of differentiation and histologic subtypes of thyroid cancer. Follicular thyroid cancer is the most common histologic origin of bone metastasis among well-differentiated thyroid cancer, with incidences ranging from 7% to 28% [4,5], but papillary thyroid cancer has been identified as the least likely subtype to cause bone metastases with incidences ranging from 1.4% to 7% in many reports [6][7][8]. According to the time interval from thyroid cancer diagnosis to detection of distant metastasis, metastatic thyroid cancer is classified into two types: synchronous metasatsis (SM) and metachronous metastasis (MM). The differences between these two

Clinical Features and Prognostic Factors for Survival in Patients with Poorly Differentiated Thyroid Carcinoma and Comparison to the Patients with the Aggressive Variants of Papillary Thyroid Carcinoma

“…It has been widely accepted that these variants of PTC are classified with the PDTC [1,4,8,9,24]. With regard to clinical features, the diffuse sclerosing variant of PTC was more aggressive in tumor size, cervical lymph node invasion and recurrence rate than classic PTC [25][26][27]. However, its overall survival rate was not significantly different from that of classic PTC.…”

Early prognostic factors at the time of diagnosis of bone metastasis in patients with bone metastases of differentiated thyroid carcinoma

“…Most previous studies categorize metastatic lesions as synchronous or metachronous (5,9,11,12). Synchronous metastasis is defined as the presence of a distance metastasis at the time of, or within a few months of, the initial diagnosis and includes patients whose metastatic lesions were found on the initial post-therapeutic wholebody scan (WBS) (RxWBS) after radioactive iodine (RAI) therapy (RAIT).…”

Clinical features of bone metastasis for differentiated thyroid carcinoma: A study of 21 patients from a Tunisian center

“…Differences in results may be attributed to population characteristics, the factors taken into account, and treatment used. [15161718] Based on available data, the only treatment option is usually palliative care in patients with DTC, although some teams are starting to offer more aggressive treatment for curative purposes.…”