CLINICAL THYROIDOLOGY FOR THE PUBLIC
A publication of the American Thyroid Association
Summaries for the Public from recent articles in Clinical Thyroidology
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THYROID CANCER
Large “benign” variants of papillary thyroid cancer (NIFTP) have a very low risk of cancer recurrence
BACKGROUND
Papillary thyroid cancer is the most common cause of thyroid cancer. The follicular variant of papillary thyroid cancer accounts for the majority of thyroid cancer cases in the United States. In 2016, the encapsulated follicular variant of papillary thyroid cancer with no evidence of spread into the thyroid capsule or into the blood vessels seen under the microscope was renamed as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), and was suggested that it was a non-cancer diagnosis. Because a study showed that patients with NIFTP had an excellent prognosis without recurrence, it is no longer recommended for patients with NIFTP to have additional treatments such as completion thyroidectomy surgeries or radioactive iodine therapy.
The current study looked at patients with large (>4cm) NIFTP to determine whether the prognosis and recurrence risk remains low even though the tumors are big. The authors want to make sure that patients can be reassured that the renaming of a cancer to a non-cancer diagnosis (NIFTP) is appropriate for large tumors and that additional treatments such as radioactive iodine therapy would not be required.
THE FULL ARTICLE TITLE:
Xu B et al. Outcome of large noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). Thyroid. 2017 Apr;27(4):512-517.
SUMMARY OF THE STUDY
A group of 4 hospitals reviewed their databases of patients who had thyroid surgery between the years 1982 to 2015. They found 79 cases that met criteria for NIFTP tumors greater than 4 cm. The patient files were reviewed to get information about management and patient outcomes. There were more women than men (ratio 1.8:1). The average size of the NIFTP tumors was 4.5 cm (ranging from 4 to 8 cm). The tumors did not extend beyond the thyroid, and of the 25 patients who had lymph nodes removed at the time of surgery, none had cancer metastases.
The average time of follow up was 5.8 years (range from 0.3 to 7.9). A total of 26 of the 79 patients had half of their thyroid removed (lobectomy) and the rest had total thyroidectomy. A total of 42 patients of the 79 had radioactive iodine therapy and most of those treated with radioactive iodine therapy had tumors larger than 5 cm.
During the follow up period, there were no cancer metastases or cancer related deaths in any of the patients with the NIFTP diagnosis, including those 25 patients who did not get radioactive iodine therapy.
WHAT ARE THE IMPLICATIONS OF THIS STUDY?
The encapsulated follicular variant of papillary thyroid cancer without capsular or vascular invasion has been renamed to a non-cancer diagnosis called NIFTP. The long-term prognosis of NIFTP tumors appears to be excellent without risk for developing metastatic disease. The authors of this study confirmed that even large NIFTP tumors over 4 cm in size have an excellent prognosis without metastatic potential. However, half of the patients in the study got radioactive iodine therapy and we don’t know what effect that might have had on their long-term outcome. Therefore, it is important for patients and clinicians to understand that aggressive management is not recommended for NIFTP tumors, but patients should have continued follow up.
— Wendy Sacks, M.D.
ATA THYROID BROCHURE LINKS
Thyroid Cancer (Papillary and Follicular): https://www. thyroid.org/thyroid-cancer/
ABBREVIATIONS & DEFINITIONS
Papillary thyroid cancer: the most common type of thyroid cancer. There are 4 variants of papillary thyroid cancer: classic, follicular, tall-cell and noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP).
Noninvasive follicular thyroid neoplasm with papillarylike nuclear features (NIFTP): a new term has been used to describe a type of papillary thyroid cancer which is non-invasive. These cancers behave less aggressively than typical papillary thyroid cancer and have been shown to have low risk for recurrence and low risk for spread outside of the thyroid.
Thyroidectomy: surgery to remove the entire thyroid gland. When the entire thyroid is removed it is termed a total thyroidectomy. When less is removed, such as in removal of a lobe, it is termed a partial thyroidectomy.
Lobectomy: surgery to remove one lobe of the thyroid.
Completion thyroidectomy: surgery to remove the remaining thyroid lobe in thyroid cancer patients who initially had a lobectomy.
Total thyroidectomy: surgery to remove the entire thyroid gland.
Cancer metastasis: spread of the cancer from the initial organ where it developed to other organs, such as the lungs and bone.
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