Traditionally, surgery has been the standard recommendation for treating papillary thyroid cancer. The risk of surgery including permanent hoarseness, permanent hypocalcemia, a mid-cervical scar, and the potential for permanent hypothyroidism may be unacceptable for some patients, especially with low risk papillary thyroid carcinoma. The recent American Thyroid Association guidelines have proposed the option of active surveillance with low risk papillary thyroid cancer less than 210 mm. However, most patients find observation anxiety provoking knowing of having cancer. Radiofrequency ablation (RFA) of small low risk papillary thyroid cancer is a promising therapeutic modality for these patients that reduces the risks associated with surgery and the anxiety of taking a watchful approach. However, this technique has not been validated in the North American population.

The investigators aim to describe the investigators' initial experience with RFA of low risk papillary thyroid microcarcinoma (PTMC) compared to active surveillance (AS) done by Head and Neck Endocrine surgeons at Johns Hopkins Medical Institute.

Primary objective:

• To evaluate the safety, efficacy and oncological outcomes of the procedure.

Secondary objective:

• To determine the patient functional outcomes in comparison to the observational control.

Inclusion Criteria:

• All patients regardless of sex or race between the ages 18-100 with biopsy proven PTMC with a Bethesda V or VI pathology or indeterminate cytology on fine-needle aspiration cytology (FNAC) who are recommended for treatment (Bethesda III/IV).
• Solitary thyroid nodule <20mm in maximal dimension.
• No sonographic evidence of extrathyroidal invasion, lymph node metastases, or distant metastases.
• There must be at least 1 mm of normal tissue as a margin, without sonographic evidence of contact with the capsule.

Exclusion Criteria:

• Patients with other histological types of thyroid malignancy other than papillary thyroid cancer such as medullary carcinoma, Proto-oncogene serine/threonine kinase (BRAF) or Telomerase reverse transcriptase (TERT) mutations
• Clinically apparent multicentricity
• Lesions larger than 20 mm in maximum diameter.
• Recurrent laryngeal nerve palsy.
• Extension of nodule to posterior thyroid capsule.
• Ultrasound or other imaging studies revealing cervical lymph node involvement or distant metastases.
• Pregnancy.
• Pacemaker.
• Previous RFA.