Well-differentiated thyroid cancer is something of an
anomaly in the field of oncology for two primary reasons. First, the team of
physicians who manage the patient consists primarily of endocrinologists,
endocrine surgeons, and nuclear medicine physicians instead of medical
oncologists, surgical oncologists, and radiation oncologists. Second, there is
an extremely high rate of cure with remarkable 10- and 20-year survival rates
due to the indolent nature of the tumor, even in the setting of lymph node
Dr. Angelos presents a thoughtful review of well-differentiated thyroid
cancer, highlighting key issues in diagnostic evaluation, surgical treatment,
and postoperative adjuvant radioactive iodine. He discusses the controversial
areas associated with treatment of the diseaseie, the extent of surgery and
the management of patients with elevated thyroglobulin as the only indication of
The benefits and limitations of the diagnostic studies available to evaluate
a thyroid nodule are also reviewed in this article. Although fine-needle
aspiration (FNA) examined by an experienced cytologist is the key study that
determines appropriate surgical management, ultrasound and nuclear medicine
scans provide specific benefits in certain clinical situations.
The principle benefit of ultrasound is in assessing the size of lesions and
evaluating for other occult thyroid nodules, as pointed out by the author. The
current recommendation is that only thyroid nodules measuring > 1 cm in two
dimensions warrant biopsy. Ultrasound may identify other nonpalpable lesions
that are large enough to be assessed by FNA. A second use of ultrasound is to
guide the FNA. As pointed out by the author, nonpalpable lesions are
increasingly being identified by other diagnostic tests, and ultrasound is
essential in guiding the biopsy of these lesions. However, ultrasound may be
used even for palpable nodules that are nondiagnostic on initial FNA because of
bloody aspirate or minimal material. Ultrasound-guided biopsies allow placement
of the needle into viable nonnecrotic sections of the nodule.
Nuclear medicine scans generally provide little additional information
because even though virtually all malignant nodules are cold on iodine scan, the
majority (80% to 83%) of cold nodules are still benign. The most important use
of iodine-uptake scanning in patients with multiple nodules is in identifying
hypofunctional lesions that should be studied with FNA.
Issues Regarding Cytologic Diagnosis
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