by Mary J. Shomon

October, 2002 -- According to research reported at the May 2002 meeting of the American Association of Clinical Endocrinologists (AACE), one fourth of benign thyroid nodules show signs of growing at all, and even then, five years is typically required for nodule growth to be significant enough to even be detectable by sensitive ultrasound tests. This finding, according to researchers, means that in most cases, annual ultrasound testing of patients with benign thyroid nodules is not necessary.

As much as half of the population have thyroid nodules, and 4 to 7 percent are detectable by manual palpation. Of all the nodules, less than 5 percent, however, are malignant. Benign thyroid nodules do not require treatment unless they cause hyperthyroid symptoms, or are growing and pose a risk to breathing or swallowing. According to the researchers, during a typical five year period, a fourth of the primary nodules (defined as a single nodule, or the dominant, largest nodule) grew. More than half remained the same size, 14% shrank, and 6% disappeared completely. Among those that grew, an average of 4.5 years was required before the growth was detectable. None of the secondary nodules grew. While the study's authors did not suggest what the optimal interval should be for conducting ultrasound testing of benign nodules, the shortest period in which any growth was observed at all was 2 years.

Source: May 2002 annual meeting of the American Association of Clinical Endocrinologists (AACE)