Shifting Paradigms in Thyroid Cancer Follow-Up

What needs to be in the follow-up of certain patients who have undergone treatment for thyroid cancer? Uncertainties still exist, but change is in the air. The 2009 American Thyroid Association (ATA) guidelines promise to clarify at least some issues that affect practice. Details were presented in a keynote talk given at the recent World Congress on Thyroid Cancer in Toronto by David Cooper, MD, Professor of Medicine and Endocrinology at Johns Hopkins University School of Medicine in Baltimore, who chaired the ATA 2009 Thyroid Cancer Guidelines Task Force.

Most patients with thyroid cancer present with isolated disease, or with lymph node involvement, but rarely do people present with more advanced disease, Dr. Cooper said. The recurrence rate ranges from 10% to 30%, depending on the nature of the tumor. People in the field assume that if recurrences are detected and treated sooner rather than later, morbidity and mortality would be decreased. However, evidence suggests that select low-risk patients may benefit equally from a watch-and-wait approach.

Use of Thyroglobulin Measurements

Detection techniques today, such as stimulated thyroglobulin (Tg) and high-resolution ultrasound, are far more sensitive than they were even two decades ago, meaning that recurrences (which many researchers consider as part of persistent disease) can be detected fairly early.

What is not clear at this point is whether the detection of these small-volume recurrences is really going to benefit the person if we find them sooner rather than later, he said. Many recurrences, if detected later, can still be treated effectively. Admittedly, some would not be as treatable, which is part of the dilemma pertaining to the value of early detection. A way to deal with this is to risk-stratify the patients, something recommended in the guidelines, he said.

A pivotal study published in 2001 showed that risk of recurrence corresponds strongly with age. When you’re young, the recurrence rates are high; when you’re old, they are high; and in the middle age range, your recurrence rates aren’t that high, he said.

I think our guidelines have helped push along the concept that once a patient has been proven to be free of disease, it is no longer necessary to keep their serum TSH suppressed.

–David S. Cooper, MD

Along with age, the ATA guidelines add that the low-risk patient is one who has no detectable residual disease, has typical tumor histology, and no 131-iodine uptake outside the thyroid bed. Intermediate-risk patients have microscopic invasion of tumor in the perithyroidal soft tissues, whereas high-risk patients have macroscopic tumor invasion along with other evident risk factors.