Impact of extrathyroidal autoimmune diseases on clinical features and the efficacy of Iodine‐131 therapy in patients with differentiated thyroid cancer

TL;DR

This study examines how autoimmune diseases outside the thyroid affect thyroid cancer patients' treatment with iodine-131 and finds no significant impact on treatment efficacy.

Contribution

The study reveals that autoimmune diseases do not affect iodine-131 therapy outcomes but may require higher levothyroxine dosages.

Findings

Autoimmune diseases do not impact iodine-131 therapy efficacy in thyroid cancer patients.

Patients with autoimmune diseases may need higher levothyroxine dosages per weight.

Autoimmune diseases might aid in detecting thyroid cancer in elderly women.

Abstract

The aim of this study is to assess the impact of extrathyroidal autoimmune diseases (ADs) on the clinical characteristics and efficacy of iodine‐131 (131I) therapy in patients with differentiated thyroid cancer (DTC).

Patients with DTC who were received 131I therapy simultaneously were classified into the combination group (n = 35) and noncombination group (n = 146) depending on the presence of ADs. The clinical characteristics, such as gender, age, tumor lesions, lymph node metastasis, distant metastasis, 131I therapy efficacy, and use of levothyroxine, were compared between the two groups. Statistical analysis was conducted using SPSS 26.0 and R 4.0.3.

There was a statistically significant difference in age between the combination and noncombination groups (t = −2.872, p < .01), and the optimal cutoff value was 50.5 years. Propensity score matching was completed effectively on a total of 121 patients, using age as the matching factor, comprising 32 cases in the combination group and 80 cases in the noncombination group. The baseline demographic features of the two groups were equivalent after matching (p > .05), and there was no significant difference in the therapeutic efficacy of 131I between the two groups (p > .05). In the subgroup analysis involving patients aged great than 50.5 years, the levothyroxine/weight (µg/kg) was increased in the combination group, and the difference was statistically significant (p < .05).

While extrathyroidal ADs may enhance the detection of DTC among elderly women, they have no impact on the clinical characteristics of thyroid cancer or the efficacy of 131I therapy. ADs may necessitate higher per‐unit dosages of levothyroxine in patients with DTC, regardless of the clinical status. Consequently, it is not essential for nuclear medicine physicians to consider the presence of ADs when designing treatment plans for patients with DTC.