Approach to the patient with a positive serum thyroglobulin and a negative radioiodine scan after initial therapy for differentiated thyroid cancer.
The 10-yr survival of differentiated thyroid cancer is about 76-93%, and at least 10% of patients manifest tumor persistence or recurrence, depending on their disease stage, after initial therapy, which typically includes total thyroidectomy and (131)I ablation. Previously the realization of their residual/recurrent cancer often presented simultaneously with the additional surprise that they lacked pathological uptake on their diagnostic whole-body radioiodine image despite their elevated stimulated serum thyroglobulin (Tg) level, a scenario referred to as the scan-negative, Tg-positive patient. Now that serum Tg and neck ultrasonography have supplanted the diagnostic whole-body scan because of its inferior sensitivity, patients are often recognized to harbor residual disease without radioiodine imaging, and a new challenging scenario has emerged: the ultrasonography-negative, Tg-positive patient. Similarities and differences of these two patient populations aside, these Tg-positive patients are frequently encountered, and some are considered for additional (131)I therapy, although now typically after negative anatomic +/- (18)F-fluorodeoxyglucose positron emission tomography imaging or in the setting of known or suspected distant metastases already localized by anatomic imaging. Thus, the scan-negative, Tg-positive patient of today differs from those of the past, but the term still has relevance to current practice. The optimal evaluation and treatment of these patients remain controversial, partly because many of these patients will not die from thyroid cancer, and there are no randomized trials to demonstrate that intervention could have prevented the deaths that do occur. Here a case is presented that adds the complexity of advanced age, and one approach to these challenging patients is offered.
Kloos
Richard T
RT
The Ohio State University, 446 McCampbell Hall, 1581 Dodd Drive, Columbus, OH 43210-1296, USA. richard.kloos@osumc.edu
D019788:Fluorodeoxyglucose F18; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D009333:Neck / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood / Q000175:diagnosis / Q000532:radiotherapy*; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
D007457:Iodine Radioisotopes; D019788:Fluorodeoxyglucose F18; D013954:Thyroglobulin