1. Prevalence of Hot Thyroid Nodules Suspicious for Malignancy
SAT 272
Prevalence of Hot Thyroid Nodules Suspicious for Malignancy
Diana J. Chang1, Stephen Lippman1,2, Alison Semrad1, Arthur Swislocki1,2
1University of California, Davis, School of Medicine 2VA Northern California Health Care System
ABSTRACT
METHODS
RESULTS
DISCUSSION
Purpose of Study:  To estimate the prevalence of thyroid nodules suspicious for malignancy in hyperthyroid patients. While contemporary guidelines emphasize that “hot,” or toxic nodules are unlikely to be malignant, case reports suggest that these nodules may be malignant in a small, but not insignificant number of individuals.  The prevalence of malignancy in “hot nodules” is unknown.
Methods used: This retrospective study analyzed data from the VA Northern California Health Care System for patients enrolled between January 2010 and December 2014.  Veterans were identified by ICD-9 codes for hyperthyroidism, and either thyroid nodules, thyroiditis, thyroid adenoma, or goiter.  Veterans who underwent radioiodine or ultrasound thyroid scanning were identified. These records were subsequently reviewed manually for suspicious ultrasonographic findings (size, calcification, or geometry).   
Summary of Results:  760 Veterans were identified by ICD-9 coding. Of these, 230 had thyroid ultrasounds, and 113 had radioiodine thyroid scans.  There were 70 patients that had both ultrasound and radioiodine thyroid scans of which 84.3% were male and the average age was 62.9.  Twenty-five had hyperthyroid nodules or areas on radioiodine studies and 31 had suspicious ultrasound scans (we excluded 11 individuals with “cold” thyroid scans). 18 had both and of these, 6 underwent fine needle aspirate (FNA) and 1 is planned for FNA.
Conclusions:  While most Veterans identified as hyperthyroid did not undergo imaging studies, of those who did, a remarkable number had heretofore unexpected ultrasonographically-suspicious nodules.  This preliminary observation suggests that ultrasound scans, a noninvasive and relatively inexpensive diagnostic modality, may have a role in the evaluation of the hyperthyroid patient in identifying those who might benefit from FNA.
Disclosures: Authors have no significant conflicts of interest to disclose
This was a retrospective study analyzed data from the VA Northern California Health Care System for patients enrolled between January 2010 and December 2014
Veterans identified by the following ICD-9 codes: (hyperthyroidism), (toxic multinodular goiter), (toxic nodular goiter), (toxic uninodular goiter) and (adenomatous goiter)
Veterans who underwent radioiodine or ultrasound thyroid scanning were identified
Records subsequently reviewed manually for total number of nodules, hot/hyperfunctioning nodules on radioiodine scans, and suspicious findings on ultrasound (microcalcifications, hypoechoic, infiltrative margins, taller than wide on transverse view, increased nodular vascularity)2.
The prevalence of suspicious findings concerning for malignancy in hot nodules was 36.3% (16/44) based on the new 2015 American Thyroid Association guidelines.
Although no cancers were detected in this cohort, majority did not undergo fine needle aspiration.
Differences in the number of suspicious nodules identified between the 2009 and 2015 ATA guidelines is attributed to the lack of “increased nodular vascularity” as a suspicious finding concerning for malignancy on the new guidelines.
The current ATA guidelines recommend that hot nodules found on scintigraphy need no further cytological evaluation because they are mostly benign.3 There is no clear stance on use of ultrasound in hot nodules.
Limitations of the study included a patient population of mostly men (84.3%) that can not be applied to the general population. Thyroid nodules are 4 times more common in women than men.4 Also as a retrospective study, there was unavoidable selection bias.
Our preliminary observation suggests that ultrasound scans, a noninvasive and relatively inexpensive diagnostic modality, may have a role in the evaluation of the hyperthyroid patient in identifying those who might benefit from FNA.
Patients with both thyroid ultrasound and radioiodine thyroid scans
(n = 70)
Total Nodules
121
Hot Nodules 44
Per 2015 ATA Guidelines
Hot Nodules WITH suspicious features on ultrasound 16
Hot Nodules WITHOUT suspicious features on ultrasound 28
Per 2009 ATA Guidelines 25 19
Coexisting Nodules (nodules found in patients WITH hot nodules) 29
Other Nodules (nodules found in patients WITHOUT hot nodules) 48
Excluded 11 patients with cold nodules and 16 patients with no nodules
Patients under the following ICD-9 codes: (hyperthyroidism), (toxic multinodular goiter), (toxic nodular goiter), (toxic uninodular goiter) and (adenomatous goiter)
(n=760)
Patients with thyroid ultrasound
(n = 230)
Patients with both thyroid ultrasound and radioiodine thyroid scans
(n = 70)
Patients with radioiodine thyroid scans
(n = 113)
PATIENT SELECTION
OBJECTIVE
Our specific aim was to estimate the prevalence of thyroid nodules suspicious for malignancy in hyperthyroid patients in a VA population
Per 2009 ATA Guidelines
18 patients with Hot nodules + Suspicious findings on US
9 patients with no FNA
6 patients had FNA – 5 benign and 1 nondiagnostic
1 patient planned for FNA
1 patient with previous thyroidectomy. No pathology available
1 patient switched providers
BACKGROUND
Hot thyroid nodules have historically been associated with low risk for malignancy therefore traditional evaluation did not warrant further evaluation with ultrasound.
However, recent case series have documented the incidence of thyroid cancer in hot nodules may be significantly underestimated. Latest 2013 literature review revealed prevalence of malignancy in patients with solitary hyperfunctioning thyroid nodules ranged from % and averaged 3.1%1
REFERENCES
Mirfakhraee S, Mathews D, Peng L, Woodruff S, Zigman JM. A solitary hyperfunctioning thyroid nodule harboring thyroid carcinoma: review of the literature. Thyroid Res. 2013;6(1):7.
Cooper D. S., Doherty G. M., Hauge B. R., Kloos R. T., Lee S. L., Mandel S. J., et al  The American Thyroid Association (ATA) guidelines taskforce on thyroid nodules and differentiated thyroid cancer. Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer. Thyroid 19:1167
Haugen BRM, Alexander EK, Bible KC, et al American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid
Mazzaferri EL. Management of a solitary thyroid nodule. N Engl J Med.1993;328(8):553–9.
Per 2015 ATA Guidelines
12 patients with Hot nodules + Suspicious findings on US
6 patients with no FNA
4 patients had FNA – all benign
1 patient planned for FNA
1 patient switched providers
Demographics
Male - (59/70) 84%
Female – (11/70) 16%
Average Age 62.9
CONTACT
Diana Chang, MS4: