Thyroidectomy for PTMC: less complications, more recurrence with partial vs total removal

In a systematic review and meta-analysis of studies on primary surgical treatment outcomes for individuals with papillary thyroid microcarcinoma (PTMC; ≤1.0 cm at greatest diameter), hemithyroidectomy (HT) was associated with lower risks of postoperative complications but a higher incidence of overall recurrence compared with total thyroidectomy (TT).

“TT has historically been the primary treatment [for PTMCs, which] have been associated with increased thyroid cancer incidence in recent decades,” said the researchers. “[However, TT] is associated with a higher surgical complication risk profile, greater cost, and longer hospital stay than HT.” [Ann Surg Oncol 2014;21:3844-3852; Ann Surg Oncol 2016;23:3641-3652]

TT also requires lifelong thyroid hormone replacement therapy, which adds to the healthcare utilization, cost, and quality of life (QoL) burden. [ORL J Otorhinolaryngol Relat Spec 2013;75:6-17; J Clin Endocrinol Metab 2012;97:2243-2255; Cancer Med 2021;10:1989-2002]

“More recent guidelines recommend HT and surveillance for low-risk differentiated cancers with specific sonographic features … [H]owever, the risk-benefit ratio of the two operations is incompletely characterized,” they continued.

The analysis included 1,416 patients undergoing HT (pooled mean age 47 years, 85 percent female) and 2,411 undergoing TT (pooled mean age 48.8 years, 77 percent female). [JAMA Otolaryngol Head Neck Surg;doi:10.1001/jamaoto.2022.0621]

Fewer postop complications

Compared with TT, HT was tied to lower risks of temporary vocal fold paralysis (VFP; 3.3 percent vs 4.5 percent; weighted risk ratio [WRR], 0.4) and hypoparathyroidism (2.2 percent vs 21.3 percent; WRR, 0.1 [temporary] and 0.0 percent vs 1.8 percent; WRR, 0.2 [permanent]).

The lower risks with HT vs TT remained even after excluding studies with high risk of bias (3.3 percent vs 4.2 percent; WRR, 0.2 [temporary VFP], 1.7 percent vs 14.7 percent; WRR, 0.05 [temporary hypoparathyroidism] and 0.0 percent vs 1.6 percent; WRR, 0.1 [permanent hypoparathyroidism]).

“As most of the studies were published in the last decade, these data are primarily from an era in which intraoperative nerve monitoring was commonplace, which may have played a role in reducing complication rates,” the researchers explained.

It is important to note however that temporary complications can last from weeks to months and may have a substantial impact on QoL and costs, they pointed out. “[C]linicians tend to focus on complications causing permanent disability; temporary complications should not be minimized,” they stressed.

 

Higher overall recurrence rate

In terms of recurrence, HT was tied to a higher overall recurrence rate than TT (3.8 percent vs 1.0 percent; WRR, 2.6). Nonetheless, this may have been driven by the higher contralateral lobe recurrence rate (2.3 percent vs 0.0 percent) which, according to the researchers, “may instead represent discrete and independent cancer in the remaining lobe.” [Thyroid 2001;11:877-881]

Recurrence rates in the thyroid bed (0.3 percent vs 0.2 percent; WRR, 0.8) and neck (1.2 percent vs 0.8 percent; WRR, 0.6) were similar. No cases of distant metastasis or mortality due to thyroid cancer have been reported.

 

Guide to treatment decisions

Despite the increase in use of HT for treating PTCs following the release of the 2014-2015 American Thyroid Association guidelines, TT remains the most common surgical approach for all T-stage categories. [JAMA Otolaryngol Head Neck Surg 2022;148:99-106; Surgery 2019;166:349-355] Up to three-quarters of PTMC cases are treated with TT. [Am J Surg 2021;221:448-454]

“The choice between TT and HT for PTMC requires surgeons and patients to weigh surgical complication risk with risk of recurrence … Treating clinicians must be aware of complication risks so they can appropriately counsel patients,” said the researchers.

“[Our findings] help characterize and quantify current knowledge of the risk-benefit ratio of HT compared with TT for the treatment of PTMC and provide data that may have utility for patient counselling surrounding treatment decisions,” they concluded.