Morphological changes of the thyroid gland as a new radiographic marker for lung cancer treatment efficacy of immune checkpoint inhibitors

Relationship between Thyroid CT Density, Volume, and Future TSH Elevation: A 5-Year Follow-Up Study

This study aimed to explore the relationship between thyroid-stimulating hormone (TSH) elevation and the baseline computed tomography (CT) density and volume of the thyroid. We examined 86 cases with new-onset hypothyroidism (TSH > 4.5 IU/mL) and 1071 controls from a medical check-up database over 5 years. A deep learning-based thyroid segmentation method was used to assess CT density and volume. Statistical tests and logistic regression were employed to determine differences and odds ratios. Initially, the case group showed a higher CT density (89.8 vs. 81.7 Hounsfield units (HUs)) and smaller volume (13.0 vs. 15.3 mL) than those in the control group. For every +10 HU in CT density and -3 mL in volume, the odds of developing hypothyroidism increased by 1.40 and 1.35, respectively. Over the course of the study, the case group showed a notable CT density reduction (median: -8.9 HU), whereas the control group had a minor decrease (-2.9 HU). Thyroid volume remained relatively stable for both groups. Higher CT density and smaller thyroid volume at baseline are correlated with future TSH elevation. Over time, there was a substantial and minor decrease in CT density in the case and control groups, respectively. Thyroid volumes remained consistent in both cohorts.

PD-1/PD-L1 inhibitor treatment and its impact on clinical imaging in non-small cell lung cancer: a systematic review and meta-analysis of immune-related adverse events

Background

In the contemporary era of cancer treatment, lung cancer (LC) holds the unenviable position of being the primary contributor to cancer-induced mortality worldwide. Although immunotherapy has expanded the therapeutic landscape for metastatic non-small cell lung cancer (NSCLC), the advent of immune checkpoint inhibitors has been accompanied by a concomitant increase in immune-related adverse events (irAEs). Timely detection of irAEs is pivotal for efficacious management and enhanced patient outcomes. Diagnostic imaging, encompassing x-ray and CT scans, can facilitate the identification and supervision of irAEs, thereby ensuring the prompt recognition of associated patterns and alterations for expeditious treatment.

Methods

The present inquiry undertook a systematic exploration of multiple databases, incorporating a diverse array of studies such as randomized controlled trials and observational analyses. Patient demographics, imaging outcomes, and risk of bias were extracted from the data. Meta-analysis was executed utilizing R Statistical Software, with the results of the risk of bias assessment summarized accordingly.

Findings

The analysis unveiled a higher prevalence of irAEs in patients receiving first-line treatment for NSCLC compared to those receiving subsequent treatments, with a statistically significant distinction observed for both high- and low-grade irAEs (p < 0.001). Pneumonitis, thyroiditis, and colitis emerged as the most frequently reported irAEs, whereas hepatitis and pancolitis were less commonly documented. This investigation signifies a crucial advancement in elucidating the function of imaging in the treatment of NSCLC with PD-1/PD-L1 inhibitors and emphasizes the imperative for ongoing research in this domain.

Computed tomography imaging findings of nivolumab-induced thyroid dysfunction

The thyroid gland is most frequently involved in immune-related adverse events (irAEs) by nivolumab. We reviewed the thyroid function and thyroid gland volume and volume change ratio between baseline and follow-up CT (volume follow-up/volume baseline) in 24 patients treated with nivolumab for lung cancer and renal cell carcinoma. Among them, four (16.7%) demonstrated nivolumab-induced thyroid dysfunction that shows either hypothyroidism or hyperthyroidism. Three and one cases were treated with nivolumab for lung cancer and renal cell carcinoma, respectively. Two patients with hypothyroidism (cases 1 and 2) showed reduced thyroid volume (volume change ratio: 0.80 and 0.84) on computed tomography (CT) images. Besides, remarkably diminished CT attenuation of the thyroid gland was observed in a patient with hypothyroidism (case 2). One of the two patients with hyperthyroidism showed increased thyroid volume (volume change ratio: 1.32) (case 3), whereas no difference in the thyroid gland volume was observed between the previous and follow-up CT in another patient with hyperthyroidism (case 4). Thyroid volume change ratio >0.1 was observed even in 6 of 20 (30%) patients without thyroid dysfunction. Considering the wide use of nivolumab in cancer treatment, radiologists should be aware that changes in the thyroid volume and attenuation on CT are associated with thyroid dysfunction caused by nivolumab, as well as thyroid volume may change even in patients with normal thyroid function during nivolumab therapy.

Thyroid-related adverse events induced by immune checkpoint inhibitors

Immune checkpoint inhibitors, namely anti-CTLA-4, anti-PD-1 and anti-PD-L1 monoclonal antibodies, have emerged in the last decade as a novel form of cancer treatment, promoting increased survival in patients. As they tamper with the immune response in order to destroy malignant cells, a new type of adverse reactions has emerged, known as immune-related adverse events (irAEs), which frequently target the endocrine system, especially the thyroid and hypophysis. Thyroid irAEs include hyperthyroidism, thyrotoxicosis, hypothyroidism and a possibly life-threatening condition known as the "thyroid storm". Early prediction of occurrence and detection of the thyroid irAEs should be a priority for the clinician, in order to avoid critical situations. Moreover, they are recently considered both a prognostic marker and a means of overseeing treatment response, since they indicate an efficient activation of the immune system. Therefore, a multidisciplinary approach including both oncologists and endocrinologists is recommended when immune checkpoint inhibitors are used in the clinic.