Leonoor E. Schonebaum1
Hossein Razaghi Siahroudi1
Sjoerd A.A. van den Berg2,3
Hannelore I. Coerts4
Tessa van Ginhoven4
W. Edward Visser1
Robin P. Peeters1
1Academic Center for Thyroid Disease, Department of Internal Medicine, Erasmus Medical Center Rotterdam, The Netherlands.
2Diagnostic Laboratory for Endocrinology, Department of Internal Medicine, Erasmus Medical Center Rotterdam, The Netherlands
3Department of Clinical Chemistry, Erasmus Medical Center, Rotterdam, Netherlands
4Department of Surgery, Erasmus Medical Center, Rotterdam (NL)
Introduction:
The 2015 ATA guidelines on medullary thyroid carcinoma (MTC) recommend performing additional imaging preoperatively when calcitonin exceeds 500 pg/mL to detect distant metastases (M1). However, this recommendation is based on a single study. Whether this is the optimal cutoff, including other diagnostic parameters, has not been evaluated in other studies. Therefore, the aims of the current study were to evaluate the current recommendation and to investigate the role of preoperative calcitonin and other possible predictors for having M1 at diagnosis.
Methods:
We retrospectively collected a cohort of patients treated for MTC in a tertiary care hospital between 1984 and 2023. We included all patients with a preoperative calcitonin measurement. The presence of M1 was detected by imaging or biopsy. The current calcitonin cut-off was evaluated by calculating diagnostic performance parameters, including sensitivity and specificity. Logistic regression was used to study the value of calcitonin and to identify new predictors for having M1 at diagnosis.
Results:
In total, 123 patients with MTC were included of which 90 were suitable for analysis. Mean age was 56 (± 16) years, 47% was female and 77% had sporadic MTC. M1 at presentation was found in 34% of all patients. Sensitivity and specificity for the current calcitonin cut-off of 500 pg/mL were 93.5% (95% confidence interval (CI) 81.4-98.9) and 45.8% (95%CI 33.4-58.5), respectively. In multivariable analysis, the presence of suspicious lymph nodes on preoperative imaging was the strongest predictor (odds ratio (OR) 19.6, 95% CI 2.11-184.3, p=0.01) followed by calcitonin (OR 1.01, 95% CI 1.00-1.03, p=0.009) for having M1.
Conclusion:
To our knowledge, this is the first study investigating the optimal combination of predictors for having M1 disease at diagnosis. Besides calcitonin, the presence of suspicious lymph nodes is a strong predictor for M1 disease. Ongoing analyses aim to further validate our results and to design a novel clinical decision tool taking into account the optimal balance between detecting M1 while minimizing unnecessary imaging.