Ethanol ablation effective long-term in metastatic papillary thyroid cancer

Reuters Health- 31/12/2021 - Ethanol ablation is safe and effective in treating metastatic lymph nodes in papillary thyroid cancer for up to 14 years, researchers say.

"We use ultrasound guidance to inject small amounts of ethanol at the correct site within the lymph nodes," Dr. Pal Stefan Frich of Oslo University Hospital told Reuters Health by email. "The technique accurately deploys the ethanol to the metastases so that normal tissue is preserved."

"Our results from ethanol ablations in 63 patients were published in 2011 (https://bit.ly/3Hr7G7z), but the data for long-term follow-up is still sparse," he said. "This prompted us to initiate this new study where we re-examined the same group of patients 8-13 years later, in order to clarify whether or not the promising short-term results were persistent also in the long run."

"We were pleased to see that most of the lesions in our study still fulfilled the response criteria and that loco-regional control in the neck region was achievable by ethanol ablations in most patients, also in the long term," he said. "The study further confirmed that local control was achieved after a limited number of injections in a limited period of time for most of the patients, without occurrence of any major or persisting side effects."

As reported in the Journal of Clinical Endocrinology and Metabolism, 51 of 63 eligible patients were included in the study. Forty-four patients were reexamined (67/109 initial lesions) and seven patients were deceased. The median age at follow-up was 64 and 59% were women. The median follow-up time from primary surgery was 14.5 years, and the median follow-up from the latest performed ethanol ablation in the 2011 study was 11.3 years.

Local control had been achieved in 80% of participants. Thirteen recurrent lesions (in 10 patients) were registered at the ablation site of earlier EA-treated lymph nodes, giving a recurrence rate at the ablation site of 19%. Ten of these lesions were in the lateral neck and the remaining three were located in the central compartment.

Seven of the residual lesions had been detected prior to the current study: one lesion responded to additional EA; four were still receiving EA; and one was followed by active surveillance at the time of study inclusion. One lesion had been surgically removed, and the patient had no sign of recurrent disease at follow-up.

The authors note, "Since EA represents a selective treatment of confirmed lymph node metastases, resembling a 'berry-picking' procedure, the risk of subsequent recurrences in locations outside of the ablation sites are of concern. We detected 'new' neck lymph node metastases in 27% (12/44) of the patients in our material. Half of these also had recurrent disease in one or more of the EA-ablation sites. The other half had persistent response in their EA-treated lesions while experiencing new lesions elsewhere in the neck."

Dr. Frich acknowledged, "The efficacy of additional ethanol treatments in recurrences on the ablation site was inferior to the overall efficacy. This also applied to the efficacy of ethanol ablations in 'new' lymph node metastases in the same patients."

"The reason for this inferior efficacy is still unclear," he said. "More aggressive disease in these patients could be a contributing factor, but this could not be confirmed by our results. Based on the experiences from this study, we suggest that a lower threshold for the consideration of other treatment alternatives than ethanol ablation should be obtained in these cases."

Dr. Ammar Chaudhry, a diagnostic radiologist at City of Hope in Duarte, California, commented in an email to Reuters Health, "As a minimally invasive approach, ethanol ablation is a safe and effective method in providing disease control."

That said, he noted, "most of the patients treated with ethanol ablation had limited disease - i.e., most had 1-3 metastatic lymph nodes - and the maximal number of tumor sites treated were six."

"The rate of recurrence is approximately 19% and, as such, patients should be followed closely after ethanol ablation therapy to ensure sustained positive response," he added. "There are limited data in patients with widespread metastasis."

SOURCE: https://bit.ly/3JyMvlO Journal of Clinical Endocrinology and Metabolism, online December 18, 2021.

By Marilynn Larkin



Posted on 31 December 202111 January 2022