Philadelphia — The use of autofluorescence-guidance during thyroidectomy in patients with differentiated thyroid cancer (DTC) showed significant benefit in the intraoperative identification of the parathyroid glands and reduced the risk for postoperative hypoparathyroidism, regardless of the degree of oncologic burden, a new study found.

These findings underscore that with autofluorescence, “we can actively prevent these complications,” first author of the study, Rossella Melcarne, MD, PhD, of the Department of General, Specialized Surgery and Anesthesiology at Sapienza University of Rome in Rome, Italy, told Medscape Medical News.

In addition, “fluorescence-guided thyroidectomy may decouple oncologic burden from postoperative parathyroid morbidity,” Melcarne and colleagues noted in their research presented at the American Thyroid Association (ATA) 2026 Meeting.

Postoperative hypoparathyroidism, caused by damage to the parathyroid glands during thyroid surgery, is among the key complications of concern with thyroidectomy or lobectomy, with the very small parathyroid glands often obscured by tissue and fat, making their detection difficult.

Among risk factors for such complications are having a greater oncologic burden, in addition to procedures performed by less experienced surgeons.

Near-infrared autofluorescence (NIRAF) and indocyanine green (ICG) angiography have emerged as key strategies to improve identification and preservation of the parathyroid glands, hence preventing the risk for postoperative hypoparathyroidism, with the latter also potentially improving vascularization, the authors noted.

A Retrospective Comparative Analysis

To further evaluate the effects of fluorescence-guided techniques on outcomes, Melcarne and colleagues conducted a retrospective comparative analysis of patients with DTC treated with thyroidectomy between January 2020 and December 2024 at two high volume centers, defined as more than 100 thyroidectomies per year.

Exclusionary criteria included having had a lobectomy, preexisting hypoparathyroidism, prior neck surgery, concomitant parathyroid surgery, preoperative parathyroid hormone (PTH) levels below the normal range, and insufficient follow-up data to determine parathyroid status at 12 months.

At center A (n = 466), the AOU Policlinico Umberto I, in Rome, Italy, all patients underwent conventional surgery, whereas at center B (n = 133), the Department of General and Endocrine Surgery, Centre Hospitalier Universitaire de Poitiers in Poitiers, France, all surgeries utilized NIRAF and ICG angiography.

The results showed that permanent postoperative hypoparathyroidism occurred in 8.8% of patients in center A compared with none (0%) at center B (P < .001).

Immediate hypoparathyroidism, defined as PTH level less than 12 pg/mL on postoperative day 1, was also significantly reduced at center B (42.5% vs 18.1%), as was transient hypoparathyroidism, defined as calcium and/or active vitamin D supplementation of 12 months or less (32.2% vs 11.3%; P < .001 for both). The results were consistent after a multivariate adjustment and propensity score matching.

Of note, in center A, increases in hypoparathyroidism corresponded with the ATA risk class, ranging from a rate of permanent hypoparathyroidism of 5% in low-risk patients to 58% in high-risk patients, with intermediate classes showing a stepwise increase (17% and 23%, respectively).

In contrast, in center B, the rates of hypoparathyroidism were uniform, with low rates across all ATA categories, and no cases of permanent hypoparathyroidism, “effectively decoupling oncologic risk from surgical morbidity,” the authors wrote.

In addition, in center B hypoparathyroidism was reduced in patients with incidental parathyroidectomy (2.3% vs 26.3%; odds ratio [OR], 0.07; P < .001) and among those without incidental parathyroidectomy, (15.9% vs 33.6%; OR, 0.37; P = .01), supporting dual mechanisms of improved gland identification as well as the preservation of vascular supply, the authors explained.

Of note, there were no differences between the groups in terms of early oncologic outcomes.

When the researchers looked at outcomes according to surgical extent, they found a strong association in patients in center A, as they had expected. However, this “association disappeared” in the center B patients, Melcarne told Medscape Medical News.

The protective association observed with NIRAF and ICG in cancers both with and without inadvertent parathyroidectomy indicates that “we have a better identification and better vascular preservation of the parathyroid glands,” she said.

Consensus Statements Support NIRAF and ICG

Most cases of postoperative hypoparathyroidism are transient, resolving within weeks; however, up to 25% of cases progress to persistent hypoparathyroidism, beyond 6-12 months after surgery, according to a recent consensus statement from the European Society of Endocrine Surgeons (ESES), the American Association of Endocrine Surgeons, and the International Association of Endocrine Surgeons.

That statement identified postoperative hypoparathyroidism as a major quality metric of thyroid surgery, and called for the standardized reporting of risk factors, surgical variables, and long-term outcomes.

A new ESES consensus on NIRAF and ICG in thyroid surgery based on an analysis of 34 studies, published last month, concluded that “promising results” were observed with this approach in terms of immediate and permanent hypoparathyroidism, inadvertent removal proportions, and autotransplantation proportions, with the quality of evidence rated as “moderate” for most recommendations.

NIRAF and ICG Complementary

Commenting on the new research presented at ATA, Pablo Moreno-Llorente, MD, PhD, of Endocrine Surgery Unit, Department of Surgery, Hospital Universitari de Bellvitge, Universitat de Barcelona, L’Hospitalet de Llobregat in Barcelona, Spain, who was a co-author on the consensus statements, noted that “these findings reinforce an important message: The more parathyroid glands we identify and preserve in situ, the greater our chances of maintaining normal parathyroid function after thyroidectomy.”

Moreno-Llorente added that “NIRAF is particularly valuable because it facilitates early identification of parathyroid tissue, sometimes before it is clearly recognizable to the surgeon. This may help prevent inadvertent removal or injury,” he explained to Medscape Medical News.

However, identification is “only the first step,” he said, noting that, the greater challenge is in “preserving the vascular supply of every gland we identify.”

“This is where I believe NIRAF and ICG angiography are complementary,” said Moreno-Llorente. “NIRAF helps us recognize the glands, while ICG allows us to understand their vascular anatomy and adapt our dissection to preserve their perfusion. The ultimate objective is not simply to identify more glands, but to leave as many viable, well-vascularized glands in situ as possible.”

Caveats and Costs

Limitations of the study included that “improved identification does not automatically translate into improved function,” Moreno-Llorente underscored.

“NIRAF tells us where the parathyroid glands are, but it does not tell us whether they are adequately vascularized,” he said. “We must also consider differences in surgical experience, the extent of surgery, the learning curve, and the relatively low incidence of permanent hypoparathyroidism, which requires sufficiently large studies and long-term follow-up.”

Furthermore, “fluorescence imaging should not encourage unnecessary dissection simply to identify every parathyroid gland,” Moreno-Llorente said.

Key barriers that may stand in the way of greater NIRAF adoption include the initial cost, equipment availability, and surgical skill, said Moreno-Llorente.

However, in a recent study of the Spanish National Health System, he and his colleagues conducted a cost-analysis and demonstrated that, with economic modeling, “ICG-guided thyroidectomy could not only improve clinical outcomes but also generate substantial long-term savings for the healthcare system.”

Moreno-Llorente noted that the applicability of the findings to other healthcare systems requires further evaluation.

Until more evidence is available, “recommendations must remain proportional to the strength of the evidence, and fluorescence should be considered an adjunct to meticulous surgical technique rather than a replacement for it,” he said.

Melcarne and Moreno-Llorente had no disclosures to report.