A second radioactive iodine treatment alone is of … - radioactive treatment for thyroid cancer

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• (1) Radiation treatment for thyroid
• (2) Radioactive thyroid ablation
• (3) Radiation therapy for thyroid
• (4) Radiation therapy for thyroid cancer

Clinical Thyroidology? for the Public
VOLUME 11 | ISSUE 3 | MARCH 2018
THYROID CANCER
A second radioactive iodine treatment alone is of little benefit in treating
patients with thyroid cancer that has spread into the lymph nodes in
the neck
BACKGROUND were divided in three groups prior to a second dose of
Thyroid cancer is the fastest rising cancer in women. radioactive iodine therapy (which they all received): 1)
Current treatment including surgery (total thyroidectomy) elevated thyroglobulin levels only with no evidence of
followed by thyroid hormone therapy. Radioactive iodine cancer in the neck by ultrasound imaging, 2) recurrent
therapy is used in patients with an intermediate or higher thyroid cancer in the neck treated with surgery, and 3)
risk of persistent or recurrent thyroid cancer. Radioactive recurrent thyroid cancer in the neck treated that was
iodine works as a "magic bullet" by getting taken up by not re-operated. Patients were followed for about 10
both normal and cancerous thyroid cells and destroying years after initial diagnosis and 7.3 years after a second
them. Similarly, radioactive iodine can be used to destroy radioactive iodine therapy. A total of 73% of the patients
thyroid cancer cells if the cancer returns. with a detectable thyroglobulin level (group 1) had per-
sistently elevated thyroglobulin levels 1-2 years after
Up to 30% of patients treated with total thyroidectomy radioactive iodine therapy; moreover, 16% of these
and radioactive iodine therapy have persistent metastatic patients developed metastatic cancer that was identified
thyroid cancer in the lymph nodes in the neck. While by ultrasound imaging. In group 2, who were re-operated
surgery is the gold standard for treatment of large prior to a second dose of radioactive iodine therapy, 48%
metastatic cancer, management of small, slowly progressive of patients had persistent cancer. Almost all patients
cancer in the neck remains unclear. Repeated doses of (94%) who did not have reoperation in the neck prior
radioactive iodine therapy has proven to be beneficial to a second radioactive iodine therapy (group 3) had
in patients with thyroid cancer that has spread outside persistent metastatic cancer at 1-2 years after the repeated
of the neck (ie into the lungs), however limited data is radioactive iodine therapy treatment. After a second dose
available on whether treatment of thyroid cancer in the of radioactive iodine therapy, about 38% of patients
lymph nodes in the neck with second administration received additional therapies.
of radioactive iodine therapy is effective. This study was
intended to determine whether a second radioactive iodine In general, at final follow up 56/164 patients (34%) had
therapy in patients with thyroid cancer in the lymph no evidence of disease and 75 patients (45%) had imaging
nodes in the neck is beneficial. studies consistent with metastatic disease. Metastatic
cancer in the neck was seen at the last follow up visit in
THE FULL ARTICLE TITLE 28% of patients with elevated thyroglobulin levels (group
Hirsch D et al. Second radioiodine treatment: limited 1), in 40% of patients who were re-operated prior to a
benefit for differentiated thyroid cancer with locoregional second dose of radioactive iodine therapy (group 2) and in
persistent disease. J Clin Endocrinol Metab. November 3, 70% of patients who were not re-operated (group 3).
2017.
IMPLICATIONS
SUMMARY This study shows that only a modest decline in metastatic
Authors selected for analysis 164 patients with thyroid neck disease was noted after a second radioactive
cancer treated with total thyroidectomy and at least two iodine therapy, unless this was also preceded by neck
doses of radioactive iodine therapy who had elevated thy- reoperation to remove metastasis. The patients who were
roglobulin levels with or without evidence of metastatic re-operated prior to a second dose of the radioactive
cancer in the neck after the initial therapy. Patients iodine therapy had the best outcomes achieving
Clinical Thyroidology? for the Public (from recent articles in Clinical Thyroidology) Page 13
A publication of the American Thyroid Association?
Clinical Thyroidology? for the Public
VOLUME 11 | ISSUE 3 | MARCH 2018
THYROID CANCER, continued
cancer-free state. These results are attributed to surgery up. Thus, it appears that patients with persistent thyroid
itself rather than to repeated radioactive iodine therapy. cancer received little benefit from a second radioactive
Furthermore, despite additional therapies that included iodine therapy. Because of this, more studies are needed
radioactive iodine therapy, surgery and external beam to evaluate the role of radioactive iodine therapy for
radiation therapy about half of the patients had recurrent cancer in the neck.
persistent metastatic disease in the neck at final follow -- Valentina Tarasova, MD
ATA WEB BROCHURE LINKS:
Thyroid Cancer (Papillary and Follicular): https://www.thyroid.org/thyroid-cancer/
Radioactive Iodine: https://www.thyroid.org/radioactive-iodine/
Thyroid Surgery: https://www.thyroid.org/thyroid-surgery/
ABBREVIATIONS AND DEFINITIONS:
Thyroglobulin: a protein made only by thyroid cells, Cancer recurrence: this occurs when the cancer comes
both normal and cancerous. When all normal thyroid back after an initial treatment that was successful in
tissue is destroyed after radioactive iodine therapy in destroying all detectable cancer at some point.
patients with thyroid cancer, thyroglobulin can be used
as a thyroid cancer marker in patients that do not have Thyroidectomy: surgery to remove the entire thyroid
thyroglobulin antibodies. gland. When the entire thyroid is removed it is termed
a total thyroidectomy. When less is removed, such as in
Radioactive iodine (RAI): this plays a valuable role removal of a lobe, it is termed a partial thyroidectomy.
in diagnosing and treating thyroid problems since
it is taken up only by the thyroid gland. I-131 is the Thyroid Ultrasound: a common imaging test used to
destructive form used to destroy thyroid tissue in the evaluate the structure of the thyroid gland. Ultrasound
treatment of thyroid cancer and with an overactive uses soundwaves to create a picture of the structure
thyroid. of the thyroid gland and accurately identify and
characterize nodules within the thyroid. Ultrasound is
Lymph node: bean-shaped organ that plays a role in also frequently used to guide the needle into a nodule
removing what the body considers harmful, such as during a thyroid nodule biopsy.
infections and cancer cells.
Clinical Thyroidology? for the Public (from recent articles in Clinical Thyroidology) Page 14
A publication of the American Thyroid Association?


What is the best treatment for thyroid cancer?Treatment of Thyroid Cancer, by Type and StagePapillary cancer and its variants. Most cancers are treated with removal of the thyroid gland (thyroidectomy), although small tumors that have not spread outside the thyroid gland may be treated ...Follicular and Hürthle cell cancers. ...Medullary thyroid cancer. ...Anaplastic cancer. ...

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