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Multifocality is not an independent risk factor for recurrence of papillary thyroid cancer

CTFP Volume 11 Issue 2


There are four different types of thyroid cancers: Papillary, Follicular, Medullary and Anaplastic. The most common type of thyroid cancer is Papillary thyroid cancer and makes up about 85% of all thyroid cancers and overall has a good prognosis. At the time of diagnosis, Papillary thyroid cancer can be seen only in one area in the thyroid gland (called unifocal) or can be seen in more than one area (called multifocal). It is not completely clear whether multifocal Papillary thyroid cancer is more aggressive and is more associated with chance of recurrence or spread outside of the neck than unifocal Papillary thyroid cancer. The most recent published guideline by American Thyroid Association for treatment of thyroid cancer, does not consider multifocality as a risk factor for higher recurrence rate. This current study has been done to evaluate the effect of multifocality on the outcome of Papillary thyroid cancer.


Wang F et al The Prognostic Value of Tumor Multifocality in Clinical Outcomes of Papillary Thyroid Cancer. J Clin Endocrinol Metab 2017; 102: 3241-50


A total of 11 medical centers from 6 countries participated in this study. A total of 2638 patients with Papillary thyroid cancer entered the study with and average age of 46 years and average follow up time of 58 months after their surgery. Of these, 76% of study subjects were women. The authors also added 89,680 patients from SEER database from 2004 to 2013.

About 38% of Papillary thyroid cancer cases were multifocal. Patients with multifocal cancer had more extension of the cancer outside of the thyroid, more spread of the cancer to the lymph nodes in the neck and more advanced staging. More patients with multifocal cancers had radioactive iodine therapy and received a higher dose of radioactive iodine.

After considering all the known risk factors causing higher recurrence into analysis, the patients with multifocal cancers did not have a higher rate of recurrence of the cancer or spread of the cancer outside of the neck and did not have a higher death rate. In analysis of 89,680 patients fro SEER database also showed that multifocal thyroid cancers did not have a higher death rate.


The conclusion of this study was that multifocal Papillary thyroid cancer is not associated with a higher death rate, recurrence or spread outside of the neck. Based on this finding, a higher dose of radioactive iodine and more aggressive treatment is not indicated for patients with multifocal Papillary thyroid cancer.

— Shirin Haddady, MD

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Thyroid Cancer (Papillary and Follicular):

Radioactive Iodine:


Papillary thyroid cancer: the most common type of thyroid cancer.

Cancer recurrence: this occurs when the cancer comes back after an initial treatment that was successful in destroying all detectable cancer at some point.

SEER: Surveillance, Epidemiology and End Results program, a nation-wide anonymous cancer registry generated by the National Cancer Institute that contains information on 26% of the United States population. Website:

Radioactive iodine (RAI): this plays a valuable role in diagnosing and treating thyroid problems since it is taken up only by the thyroid gland. I-131 is the destructive form used to destroy thyroid tissue in the treatment of thyroid cancer and with an overactive thyroid. I-123 is the non-destructive form that does not damage the thyroid and is used in scans to take pictures of the thyroid (Thyroid Scan) or to take pictures of the whole body to look for thyroid cancer (Whole Body Scan).