Temporal Trends in the Presentation, Treatment, and Outcome of Medullary Thyroid Carcinoma: An Israeli Multicenter Study.

BACKGROUND

The widespread use of neck sonography in recent years has led to a dramatic increase in the detection of thyroid cancer, accompanied by changes in the clinicopathologic features of the disease. However, small papillary carcinomas account for the bulk of this increase, while little is known about temporal changes in medullary thyroid carcinoma (MTC). The aim of this study was to evaluate trends in the presentation, treatment, and outcome of MTC.

METHODS

Patients treated for MTC at four medical centers in Israel were divided into three groups by year of diagnosis: 19811995 (period A), 1996-2005 (period B), and 2006-2016 (period C). Clinicopathologic and survival data were collected retrospectively from the medical files and compared between the groups.

RESULTS

The cohort included 182 patients (54.9% female) with a mean age of 49.2 ± 18.7 years: 43 (23.6%) diagnosed in period A, 54 (29.7%) in period B, and 85 (46.7%) in period C. No significant differences were found between the groups in primary tumor size (25.7 ± 18.9 mm, 26.6 ± 18 mm, and 23.7 ± 17.6 mm, respectively), proportion of micro-MTC (30.8%, 20.0%, and 25.3%, respectively), or TNM staging. Age at diagnosis significantly increased over time (38.7 ± 17.2 years, 51.7 ± 18.4 years, and 53.7 ± 17.7 years, respectively; p < 0.001), and the rate of familial MTC significantly decreased (41.9%, 14.8%, and 8.2%, respectively; p = 0.002). Although the implementation of cervical lymph node dissection increased (62.1%, 78.4%, and 85%, respectively; p = 0.01), detection of metastatic lymph nodes decreased from 88.9% in period A to 65.0% in periods B and C (p = 0.06). There was no difference between the groups in disease-specific survival or disease-free state at one year from diagnosis (37.5%, 43.1%, and 50%, respectively) and last follow-up (27%, 41.2%, and 48%, respectively). Similar findings on MTC presentation and outcomes were obtained when only patients with non-familial MTC were analyzed.

CONCLUSIONS

Unlike differentiated thyroid cancer, most of the presenting features of MTC have not changed over time. The most significant temporal change is a decreased rate of familial MTC. Despite more extensive surgery and the use of new treatment modalities in recent years, significant improvement in disease-related outcomes were not found.