NEW CLINICAL OBSERVATIONS REGARDING THYROID CANCER
The most recent issue of JCEM is filled with interesting studies on thyroid cancer.
Balasubramaniam S, Ron E, Gridley G, Schneider AB, Brenner AV.( Association between Benign Thyroid and Endocrine Disorders and Subsequent Risk of Thyroid Cancer among 4.5 Million U.S. Male Veterans. J Clin Endocrinol Metab. 2012 Aug;97(8):2661-9) reviewed data on 4.5 million male service veterans and found significant positive relations between a prior history of benign adenomas, nodular goiter, thyroiditis and hypothyroidism, and a subsequent diagnosis of thyroid cancer.
McLeod DS, Watters KF, Carpenter AD, Ladenson PW, Cooper DS, Ding EL. (Thyrotropin and thyroid cancer diagnosis: a systematic review and dose-response meta-analysis. J Clin Endocrinol Metab. 2012 Aug;97(8):2682-92) -conducted a meta-analysis confirming the positive relation between serum TSH levels in the normal or mildly elevated range and occurrence of thyroid cancer.
Robenshtok E, wisdom of these changes.
In a similar vein, Chindris AM, Diehl NN, Crook JE, Fatourechi V, Smallridge RC.(Undetectable Sensitive Serum Thyroglobulin (<0.1 ng/ml) in 163 Patients with Follicular Cell-Derived Thyroid Cancer: Results of rhTSH Stimulation and Neck Ultrasonography and Long-Term Biochemical and Clinical Follow-Up. J Clin Endocrinol Metab. 2012 Aug;97(8):2714-23) studied retrospectively 163 patients with DTC after surgery and RAI treatment, who had T4-suppressed Tg of 0.1ng/ml or less. They conclude that annual suppressed-Tg and periodic US are sufficient for follow-up, and that rhTSH stimulated Tgs are not needed.
In another attempt to limit possible excessive testing and procedures, Webb RC, Howard RS, Stojadinovic A, Gaitonde DY, Wallace MK, Ahmed J, Burch HB (The utility of serum thyroglobulin measurement at the time of remnant ablation for predicting disease-free status in patients with differentiated thyroid cancer: a meta-analysis involving 3947 patients. J Clin Endocrinol Metab. 2012 Aug;97(8):2754-63) , using a meta-analysis, conclude that a pre-op Tg of 10ng/ml has a high predictive value for disease free follow-up, and might be used to limit RAI ablation.
It is of interest that so many studies in recent years have been directed at limiting presumably un-needed use or RAI, surgery, or testing proceedures (WB scans, Stimulated Tgs). Historically thyroid cancer therapy was predicated on doing almost anything to achieve 100% success in control of the cancer, although this was never a realized goal. Many of the current crop of studies seem to accept a small failure rate as an acceptable trade off for a reduction in intensity of follow-up proceedures. Time will tell.