Shifting Paradigms in Thyroid Cancer Follow-Up

Generally, the role of PET scanning has expanded in the new guidelines, Dr. Cooper said. It is recognized as something that helps localize disease in Tg-positive, RAI scan-negative patients without needing to have a negative post-RAI therapy scan. PET scans should also be used for staging of disease, as a prognostic tool for patients with metastatic disease to identify those at highest risk, and for evaluation of post-treatment response.

The guidelines now emphasize risk-adapted management. Not only is the initial therapy directed toward the baseline risk of the patient, but the follow-up should also be based on the risk of the patient, Dr. Cooper said. This includes observing and acting on how risk changes over time in individual patients.

In low-risk patients, in the first two years of follow-up, it is now considered reasonable to obtain Tg levels every six months for the first two years. Once the stimulated Tg has been negative for a year, the test does not need to be repeated.

In patients with intermediate risk, it is reasonable to repeat stimulated Tg levels because disease will be detected in some of them-even if basal Tg is undetectable.

Ultrasound should be used yearly in low-risk patients for the first two years, but more frequently in intermediate- and high-risk patients (high-risk patients need to be intensively monitored in general). The guidelines now say that once a patient is disease-free, the serum TSH can be allowed to rise into the normal range in low-risk patients, but should remain <0.1 mU/L in intermediate- and high-risk patients. Dr. Cooper noted that the approach to thyroid hormone suppressive therapy needs to take into account other comorbidities a patient has (such as cardiovascular disease or osteoporosis) and factor those into the risk-benefit treatment profile for that patient.

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, he said.

©2009 The Triological Society