False positive results using calcitonin as a screening method for medullary thyroid carcinoma

Treatment and management of medullary thyroid microcarcinoma: a 10-year retrospective study from a single center

OBJECTIVE

To explore individualized treatment and management methods for medullary thyroid microcarcinoma (MTMC).

METHODS

Clinical data of patients with medullary thyroid carcinoma with a diameter ≤1 cm admitted to the First Affiliated Hospital of Kunming Medical University from June 2013 to June 20× were collected. Combined with different treatment guidelines for medullary thyroid carcinoma, factors affecting lymph node metastasis and postoperative disease status were analyzed.

RESULTS

Twenty-nine patients with MTMC were included in the analysis, including 24 patients who underwent total thyroidectomy, 5 who underwent thyroid gland lobectomy, and 13 who experienced postoperative lymph node metastasis. Multifocal tumor and calcitonin (Ctn) were the influencing factors, while multifocal tumor, Ctn, lymph node metastasis, and AJCC stage affected the dynamic risk stratification of postoperative disease.

CONCLUSION

Calcitonin detection is an important method for detecting MTMC. A tumor diameter ≤1 cm does not indicate that the tumor is in the early stage. The presence of multifocal tumors and Ctn should be used as important indicators for preoperative evaluation. Dynamic stratified risk assessment is critical in postoperative follow-up.

Cost-effectiveness of routine calcitonin screening and fine-needle aspiration biopsy in preoperative diagnosis of medullary thyroid Cancer in the United States

OBJECTIVES

examine the cost-effectiveness of routine Calcitonin (Ctn) screening test in the United States.

MATERIALS AND METHODS

Markov chain model was developed that compares fine-needle aspiration biopsy (FNAB) with Ctn screening vs. FNAB-only in the evaluation of a thyroid nodule with non-highly suspicious findings. Follow-up time was set as 10 years. Costs and probabilities values were obtained from literature, and National Cancer Database. Cost data is expressed in U.S$ and effectiveness is expressed in Quality-adjusted-life-year (QALY). Incremental cost-effectiveness ratio (ICER) was calculated comparing both study arms.

RESULTS

Routine Ctn screening was cost-effective compared to FNAB-only in all tested categories except when cutoff value of 10 pg/ml was applied. Among the tested categories, the application of universal routine Ctn screening with Ctn value > 50 pg/ml considered a positive test produced the most cost-saving scenario. The final accrued cost at the end of 10 years in the FNAB-only arm was $4238.93 with a final effectiveness of 8.717 QALY. While the final cost in the FNAB-with routine Ctn screening was $4345.04 with a final effectiveness of 8.722 QALY. ICER of routine Ctn screening compared to FNAB-only was $23278.61/QALY (<Willing-To-Pay threshold of $50,000/QALY). Based on sensitivity analyses, Ctn testing is cost-effective if the test cost is less than $236.03.

CONCLUSIONS

Routine Ctn screening is a cost-effective strategy in US if the cost is less than $236.03. Although Ctn screening is not perfect in detecting MTC at early stages, it is a cost-effective alternative of discovering MTC after thyroid lobectomy or on follow-up of a thyroid nodule.

Carcinoembryonic antigen levels correlated with advanced disease in medullary thyroid cancer

Background

Medullary thyroid cancer (MTC) cells are capable of secreting various tumor markers including calcitonin and carcinoembyronic antigen (CEA). The purpose of this study is to determine whether abnormal CEA levels may be used as a tumor marker to predict the severity of disease in MTC.

Methods

A retrospective analysis was completed for 33 patients with MTC who had preoperative serum CEA levels. Univariate and multivariate analyses were used to quantify the relationship between serum CEA levels and tumor stage and prognosis.

Results

On multivariate analysis, elevated preoperative CEA levels were significantly associated with the size and stage of tumor, distant metastasis, decreased biochemical cure, and mortality. There was a significant association between tumor size greater than 37 mm and elevated CEA levels (> 271 ng/ml). There was also a positive correlation with increased cancer stage (> 377 ng/ml), distant metastasis (> 405 ng/ml), and contralateral compartment location of lymph node metastasis (> 162 ng/ml). When pre-operative CEA levels are > 500 ng/ml, patient mortality was 67%.

Conclusion

In this study, both pre-operative calcitonin and CEA levels were significantly correlated with the extent of disease in MTC. While calcitonin has a linear relationship with disease progression, abnormal CEA levels were a better indicator of advanced disease. CEA levels > 271 ng/ml are significant for advanced tumor size and staging, metastasis to the central compartment, and decreased chance of biochemical cure. CEA levels greater than 500 ng/ml are associated with significant patient mortality.

Patients with papillary thyroid carcinoma associated with high stimulated serum calcitonin levels

Among various substances produced by C-cells, the most important one is calcitonin (CT) that is used for detection, post-operative follow-up and evaluation of individuals at risk of developing medullary thyroid carcinoma (MTC). However, the role of serum CT measurement in the evaluation of thyroid nodules has been widely discussed, and there is still no consensus about the role of CT in the initial evaluation of all thyroid nodules. Two patients with thyroid nodules whose fine-needle aspiration results were compatible with benign cytology besides having mildly elevated basal serum calcitonin levels were reported. Calcitonin responses (peak levels were 313 and 229 pg/mL, respectively) to calcium stimulation test were compatible with the possible diagnosis of MTC. However, the final diagnosis was papillary thyroid carcinoma of the thyroid gland. There are limited numbers of case reports showing such an increased serum calcitonin responses to calcium stimulation test associated with papillary or follicular thyroid carcinoma of the thyroid. We suggest to measure serum CT level once and in case of normal levels, no further CT measurement is necessary. Physicians should keep in mind that thyroid carcinomas other than MTCs may also be associated with high serum CT levels.

Learning points

Although serum calcitonin is a valuable tumor marker for MTC, it is well known that mild elevations may be seen in some other diseases such as Hashimoto thyroiditis, neuroendocrine tumors or due to medications such as proton pump inhibitors, calcium salts, beta blockers and glucocorticoids.Those two cases indicate that high calcitonin responses to calcium stimulation test, mimicking MTC, may also be seen in patients with papillary thyroid carcinoma although the mechanism is not clear.