83rd Annual Meeting of the American Thyroid Association:
Possible Prognostic Value of Circulating Tumor Cells in Medullary Thyroid Cancer
Circulating tumor cells (CTCs) are cells that a primary tumor sheds into the bloodstream. CTCs have been referred to as seeds that take root1 and metastasize beyond the primary tumor's site. CTCs are associated with breast, colorectal, and prostate cancers, and usually represent a poor prognosis.
In this poster presentation, researchers explained how CTCs were detected in blood samples taken from patients with metastatic medullary thyroid cancer (metMTC). The purpose of their study was to determine if CTCs have a prognostic value in metMTC.2
Whole blood samples were taken from 18 subjects (9 men, 9 women) with metMTC. Samples were analyzed utilizing technology to detect, isolate, and enumerate CTCs. Further testing selected cells positive for cytokeratin and 4',6-diamidino-2-phenylindole (DAPI), and negative for CD45 (lymphocyte marker).
- 6 study participants had ≥5 CTCs
- 12 study participants had ˂5 CTCs
|
Mean |
Median |
|
|
Age at diagnosis |
43 years |
52 years |
|
Calcitonin |
3918 ng/mL |
3240 ng/mL |
Metastatic Disease
|
Liver |
Lungs |
Bones |
|
89% |
72% |
67% |
Follow-up: 24.5 months after sampling, 9 patients had died.
- 5 had ≥5 CTCs
- 4 had ˂5 CTCs
- No significant differences in calcitonin doubling times
Median Survival
- ≥5 CTCs: 13 months
- ˂5 CTCs: Not reached during the study period
In this study, the survival time of patients with ≥5 CTCs was shorter, as demonstrated by Kaplan-Meier analysis. Researchers used the hazard ratio (HR) for mortality to compare patients with ≥5 CTCs with ˂5 CTCs. The HR was 4.05 (P=0.042).
This was a small patient study, and metMTC with CTCs greater than or equal to 5 showed poor survival prognoses. Larger studies are needed to determine if CTC testing is more predictive than calcitonin doubling in patients with metMTC.
