Study examines occult medullary thyroid cancer

Medullary thyroid cancer (MTC) is a relatively rare form of thyroid disease, one that is often difficult to detect, which is one reason why scientists at the Johns Hopkins University School of Medicine recently attempted to quantify the rate at which MTC goes undiscovered until a thyroidectomy.

Their results, which appeared in the Journal of Clinical Endocrinology and Metabolism, indicated that 0.3 percent of all thyroid removal surgeries reveal a case of MTC that previously went unnoticed, which the team refers to as incidental, or "occult," MTC.

The medullary variety of thyroid cancer is fairly rare. Compared to papillary thyroid cancer, which accounts for at least 70 percent of all diagnoses of the disease, MTC is extremely uncommon.

Currently, the best estimate for MTC occurrence puts it at between 3 and 4 percent of all cases of thyroid carcinoma, according to the Yale Medical Group.

The news study examined 35 years' worth of medical literature in order to determine the approximate rate of occult MTC discovery. In addition to determining that three in every 1,000 thyroidectomies reveal an undiagnosed case of MTC, the team also established that approximately 10 to 15 percent of all MTC cases are occult.

The research group noted that much of the importance of this study lay in its implications for health outcomes.

Unlike other forms of thyroid cancer, MTC has a relatively poor outlook for those diagnosed with it, and delayed detection of medullary thyroid tumors - as is the case with occult MTC - can reduce a patient's outlook.

The Columbia University Department of Surgery estimates that while early detection of MTC results in an 80 percent 10-year survival rate, unnoticed MTC that spreads to the lymph nodes or other organ systems entails a survival rate of just 25 percent over a decade.

The study's authors concluded that modifications to the cutoff values for calcitonin screening may increase the chances that occult MTC will be detected prior to surgery for other thyroid ailments.