Trends in Diagnostics, Surgical Treatment, and Prognostic Factors for Outcomes in Medullary Thyroid Carcinoma in Norway: A Nationwide Population-Based Study

Abstract

Background: Medullary thyroid carcinoma (MTC) is rare. Nationwide population-based studies are important to evaluate its clinical course. Objectives: To describe all patients with MTC in Norway during 1994–2016 and compare time-related trends in diagnostics and surgical treatment, including prognostic factors for biochemical cure and disease-specific survival (DSS). Methods: This retrospective population-based cohort study includes data for 228 out of 237 patients (96%) with MTC; 201 patients were surgically treated. Patients were identified in the 4 regional centers treating MTC and by the Cancer Registry of Norway. Data were collected from patients’ files. Trends were compared over 2 study periods. Results: MTC accounted for 4.2% of thyroid carcinomas. During the study periods, the incidence increased from 0.18 to 0.25: 100,000 per year, preoperative diagnostics improved with increased use of calcitonin, ultrasound, and fine-needle cytology (p = 0.010, p < 0,001, and p = 0.001), patients were diagnosed at an earlier tumor stage (p = 0.004), and more patients were cured (p = 0.002). Via multivariate analysis of patients with metastatic lymph nodes, independent prognostic factors for cure were: a low ratio of metastatic and total number of dissected lymph nodes (p = 0.021) and no extrathyroidal extension (p = 0.030). Independent prognostic factors for DSS were: no distant metastasis, a younger age, and a low ratio of metastatic and dissected lymph nodes (p = 0.005, p = 0.020, p = 0.022). Conclusions: Preoperative diagnostics have improved over time with increased therapeutic control. A low ratio of metastatic and dissected lymph nodes predicts better outcomes in patients with metastatic lymph nodes.

Prediction of biochemical cure in patients with medullary thyroid cancer

“…Patients achieving biochemical cure had a median of 2 versus 16 metastases at initial operation, and 4 versus 12 metastases at repeat surgery, compared with patients without biochemical cure. These data compare favourably against corresponding median values of 3·5 versus 10 node metastases from the Norwegian national registry, and against absolute thresholds of four node metastases for biochemical cure from the Danish national registry. The number of node metastases was also more powerful in predicting biochemical cure than MLNR or AJCC node category.…”

“…Of note, median MLNRs were 0·05–0·08 for patients who were biochemically cured and 0·23–0·28 for those not cured. Corresponding median MLNRs reported from a Norwegian registry study were 0·19 for patients who were biochemically cured and 0·43 for those who were not cured. In this respect, it is noteworthy that two to three times more nodes (median 57·5–64) were removed in the present study than in the Norwegian national registry (median 19–26).…”

“…Corresponding median MLNRs reported from a Norwegian registry study were 0·19 for patients who were biochemically cured and 0·43 for those who were not cured. In this respect, it is noteworthy that two to three times more nodes (median 57·5–64) were removed in the present study than in the Norwegian national registry (median 19–26). For patients with stage IV MTC, much higher MLNRs of at least 40·7 per cent for poorer overall survival, and at least 76·5 per cent for poorer disease‐specific survival have been reported.…”

“…Usually biochemical cure cannot be achieved when more than ten nodes are involved. Data from the Norwegian and Danish national registries showed a median of 3·5 lymph node metastases in patients who were biochemically cured, and an absolute threshold of four node metastases for postoperative biochemical cure.…”

Primary hyperparathyroidism as first manifestation in multiple endocrine neoplasia type 2A: an international multicenter study

“…High-resolution ultrasonography is routinely used in the preoperative setup for PHPT patients, while measurements of serum calcitonin are not (64). In some patients the preoperative serum calcitonin will likely be measured as a consequence of thyroid nodules found by ultrasonography (65,66,67,68,69). Some authors have suggested systematically preoperative calcitonin measurements in patients with apparently sporadic PHPT to exclude potential MEN 2 cases (70).…”