Survey of medical literature attempts to zero in on medullary thyroid cancer rate

Researchers at the Ohio State University (OSU) Medical Center recently published a review of 40 years' worth of autopsies in an effort to more accurately determine the rate of medullary thyroid cancer in the U.S.

Their results, which appear in the Journal of Clinical Endocrinology and Metabolism, indicate that approximately 16 in every 1,000 Americans has some form of the disease at the end of their lives, many of them over the age of 60.

Medullary thyroid cancer is rare and, as a study in the journal Thyroid puts it, "challenging in its malignancy."

In other words, the outlook for patients diagnosed with the medullary form of the disease is not as positive as that for the papillary and follicular varieties.

Compared to the latter two, whose five-year survival rates are 90 and 94 percent respectively, the rate for medullary thyroid carcinoma is 83 percent, according to the National Cancer Institute (NCI).

Much of this disparity comes from the difficulty in diagnosing medullary thyroid cancer at all. The disease occurs when the thyroid's parafollicular cells - which produce a hormone that regulates blood calcium - begin to grow out of control.

However, these tumors are often difficult to detect. Many people first discover they have the disease after going to their physician for chronic diarrhea, which is the cancer variety's most common symptom, the Columbia University's School of Medicine reports.

Since medullary carcinomas can go unnoticed, the OSU group conducted a metastudy of 24 separate reviews of patient autopsies.

They found that previously undetected, or "occult," medullary tumors were found during 16 in every 1,000 autopsies. Men and women had the condition in roughly equal proportions, and most were over the age of 60.

Researchers noted that nearly all medullary thyroid tumors were less than a centimeter wide, and none had spread to the lymph nodes or metastasized in distant parts of the body.

They concluded that people with this form of cancer may be unaware of it, and that screening procedures should take into account the disease's often occult nature.

The NCI estimates that 6 in every 10,000 cancer diagnoses among living Americans will be medullary thyroid cancer.