Incidentally discovered medullary thyroid cancer: Diagnostic strategies and treatment

Shabina R. Ahmed, Douglas W. Ball

Research output: Contribution to journalReview articlepeer-review

Abstract

Context: Medullary thyroid carcinoma (MTC) is diagnosed only after thyroidectomy in approximately 10-15% of cases. This delay in diagnosis can have adverse consequences such as missing underlying pheochromocytoma or hyperparathyroidism in unrecognized multiple endocrine neoplasia type 2 and choosing a suboptimal extent of surgery. Barriers to accurate preoperative diagnosis and management strategies after the discovery of occult MTC are reviewed. Evidence Acquisition: We reviewed PubMed (1975-September 2010) using the search terms medullary carcinoma, calcitonin, multinodular goiter, Graves' disease, calcium/diagnostic use, and pentagastrin/diagnostic use. Evidence Synthesis: The combined prevalence of occult MTC in thyroidectomy series is approximately 0.3%. Routine calcitoninmeasurementin goiter patients identifies C-cell hyperplasia as well as MTC. Challenges include interpreting intermediate values and unavailability of pentagastrin stimulation testing in the United States. Early studies have begun to identify appropriate cutoff values for calcium-stimulated calcitonin. For management of incidentally discovered MTC, we highlight the role of early measurement of calcitonin and carcinoembryonic antigen, RET testing, and comprehensive neck ultrasound exam to direct further imaging, completion thyroidectomy, and lymph node dissection. Conclusions: Occult MTC is an uncommon, but clinically significant entity. If calcium stimulation testing cutoff data become well-validated, calcitonin screening would likely become more widely accepted in the diagnostic work-up for thyroid nodules in the United States. Among patients with incidental MTC, those with persistently elevated serum calcitonin levels, positive RET test, or nodal disease are good candidates for completion thyroidectomy and lymph node dissection in selected cases, whereas patients with undetectable calcitonin, negative RET testing, and no sonographic abnormalities often may be watched conservatively.

Original languageEnglish (US)
Pages (from-to)1237-1245
Number of pages9
JournalJournal of Clinical Endocrinology and Metabolism
Volume96
Issue number5
DOIs
StatePublished - May 2011

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Endocrinology
  • Clinical Biochemistry
  • Biochemistry, medical

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