Phase III, Assessor Blinded, Randomised Controlled Trial of Use of Intraoperative Neuromonitoring (IONM) in Thyroid Cancer Surgery(ACTION)

Background and rationale of the study:

The incidence of the thyroid carcinoma has dramatically increased in the last few decades.1Total thyroidectomy with or without central compartment dissection is the treatment of choice for thyroid carcinoma. Vocal cord palsy (VCP) due to injury to the recurrent laryngeal nerve (RLN) is one of the most dreaded complications of this surgery. The symptoms associated with this complication include hoarseness of voice, voice fatigue and aspiration. Vocal cord palsy can be either temporary or permanent. The reported incidence of temporary VCP varies from 0-12%.2-4 However, the incidence of permanent VCP has been reported to be much lower varying from 0 to 3.5%.4,5Many patients may not present with symptoms of hoarseness and a post-operative laryngoscopic examination is required in all patients who have undergone surgery for thyroid cancer.6 However, the morbidity associated with VCP significantly affects the quality of life of the patient and at times require intervention to prevent aspiration or to improve voice quality.7 In a recent publication from our institute the invesigator found a temporary VCP rate of 11.8%.8

Intra operative nerve monitoring (IONM) is a technique of monitoring the RLN during surgery, to help identification and safe guarding of the nerve during total thyroidectomy as well as central compartment clearance (CCC). This is a well established technique with many centers in the world routinely using monitoring during surgery. There have been 4 RCTs and 2 meta analysis looking at the role of IONM in decreasing RLN palsy after thyroidectomy. The results from the same have been equivocal with 3 of 4 RCTs showing no added benefit in decreasing RLN palsy rates with the use of IONM.9-12 Of the 2 meta analysis, there was a decrease in RLN palsy rates in one of the meta analysis. 13 however the other Meta analysis by Higgins et al showed no improvement in RLN palsy rates with the use of IONM.14 In the meta analysis by Yang et al, published in 2016, there was a 44% (p=ns) decrease in temporary RLN palsy rates in the thyroid cancer cohort. However, the literature on use of IONM is still equivocal in literature. The other issue with available literature on use of IONM is that, most studies have looked at a heterogenous population of patients being operated for benign and malignant disease. Also most patients in the series evaluated have been patients who have undergone surgery for benign multinodular goiters. The extent of RLN dissection in these patients is limited as compared to patients undergoing surgery for thyroid cancers which involve total thyroidectomy and central compartment dissections. There have been no RCTs looking at the role of IONM in preventing RLN palsy in thyroid cancer surgeries. Also none of the RCTs performed have had a formal sample size calculation and robust analysis.

Section B: Aims and Objectives Aim: To assess the role of IONM in thyroid cancer surgery

Primary objective: