Ultrasound-guided Percutaneous Ethanol Ablation vs. Observation of Papillary Thyroid Microcarcinoma

Papillary thyroid microcarcinoma has been reported to be the most commonly diagnosed endocrine malignancy. The ATA and ETA Guidelines recommend thyroidectomy and lifelong thyrotropin suppression for papillary thyroid cancers of 1 cm or less. By contrast, a previous observational trial in Japan managed the majority of its papillary thyroid cancer patients with observation alone.

Based on the questioning of the guidelines and the willingness of patients in the USA with newly diagnosed papillary thyroid cancer (PTC) to be treated by less invasive procedures than partial or total thyroidectomy, I. D. Hay and R. A. Lee, from Mayo Clinic College of Medicine, in Rochester, MN, treated three PTC patients who had decided against surgery. “After more than two decades of employing ultrasound-guided percutaneous ethanol ablation (UPEA) in controlling nodal metastases in the postoperative necks of 146 personal PTC patients,” the study authors explained in the abstract, “we felt confident in offering UPEA of cancer foci in the intact thyroid to those patients who have decided against surgical resection of their PTMs.”

At the 83rd Annual Meeting of the American Thyroid Association, in San Juan, Puerto Rico, on October 18, 2013, the study authors announced they had successfully treated five foci of PTM in three intact thyroids and concluded that UPEA is uncomplicated, tolerated, substantially cheaper than conventional surgery, and a long-term, superior alternative to observation alone.

The first patient of this study (a 58-year-old male) had bilateral foci (5- and 9-mm diameter): a larger one (140-mm³ volume) treated with 0.7 cc and a smaller one (31 mm³) treated with 0.65 cc. At 12 months after UPEA, neither PTM had Doppler flow and both were smaller (140 to 83 and 31 to 23 mm³). The second patient (a 36-year-old female) with FDG-positive 7 mm PTM received 1.25 cc, disappeared on PET at 4 months, and was avascular and smaller (44 to 5 mm³) at 5 months. The third patient (a 53-year-old female) had bilateral foci (10 and 5 mm) treated with total 2.45 cc, and was avascular and smaller (250 to 21 and 42 to 25 mm³) at 3 months.

In summary, the researchers treated the three patients successfully, with no post-UPEA painful thyroiditis and no hoarseness or hypocalcemia. All five malignant nodules became avascular and smaller after ablation, with one of them disappearing on neck ultrasound. Although follow-up currently averages 15 months, the researchers believed initial results to be very encouraging.

The study shows that UPEA was uncomplicated and tolerated as an outpatient procedure under local anesthetic, and that for papillary thyroid microcarcinoma patients refusing thyroidectomy it may prove to be a long-term, perhaps superior alternative to observation alone. Moreover, the charge for UPEA was approximately $38,000 cheaper than a typical thyroidectomy. “If prospective trials of observation versus surgery are to occur in the USA, perhaps UPEA could possibly be included as a 'third' arm in such proposed trials,” the study authors suggested at the ATA meeting.