MEDULLARY THYROID CANCER THAT STAINS NEGATIVE FOR CA 19-9 HAS DECREASED METASTATIC POTENTIAL

Area of Science:

• Oncology
• Pathology
• Cancer Biomarkers

Background:

• Medullary thyroid cancer (MTC) lacks clinical tools for diagnosing metastatic potential at presentation.
• Current surveillance relies on calcitonin (Ct) and carcinoembryonic antigen (CEA) post-treatment.
• Carbohydrate antigen (CA)19-9 staining is emerging as a marker for aggressive MTC and metastasis.

Purpose of the Study:

• To investigate the association between positive CA19-9 staining in MTC tissue and its metastatic potential.
• To explore CA19-9 as a potential diagnostic marker for MTC aggressiveness.

Main Methods:

• Retrospective review of 16 MTC cases.
• Immunohistochemical staining of MTC tissue for CA19-9 and other tumor markers.
• Correlation of staining results with clinical staging and metastatic status.

Main Results:

• 63% of MTC specimens showed positive CA19-9 staining.
• Positive CA19-9 staining was associated with larger tumor size (median 2.6 cm vs 0.7 cm).
• All stage IV MTC and primary MTC with documented metastasis stained positive for CA19-9 (100%).
• Negative CA19-9 staining demonstrated 100% sensitivity for ruling out stage IV MTC.

Conclusions:

• Negative CA19-9 staining in MTC may correlate with reduced metastatic potential.
• CA19-9 status could potentially assist in assessing MTC metastatic risk.
• Further research is warranted to validate CA19-9 as a prognostic biomarker in MTC.