Influence of the first radioactive iodine ablation on peripheral complete blood count in patients with differentiated thyroid cancer

Advances in the selection and timing of postoperative radioiodine treatment in patients with differentiated thyroid carcinoma

Differentiated thyroid cancer (DTC) is the most common endocrine malignancy. Patients who receive systematic care typically have a better prognosis. RAI treatment plays a key role in eradicating any remaining thyroid lesions in DTC patients, hence decreasing the risk of distant metastases and cancer recurrence. As research continues to advance, RAI treatment is becoming more and more individualized. Because of the excellent prognosis for DTC patients, there is a relatively broad window for RAI treatment, making it easy to overlook when to receive RAI treatment. However, research on this issue can help patients with varying recurrence risk stratification make better decisions about when to begin RAI treatment following surgery, and physicians can schedule patients based on the severity of their disease. This will improve patient prognosis and lessen needless anxiety in addition to helping solve the problems of unjust healthcare resource distribution. In this review, we will mainly discuss the target population of RAI treatment as well as studies that examine the impact of RAI treatment timing on patient outcomes. In an effort to discourage DTC patients and physicians from selecting RAI therapy at random, we also review the possible negative effects of this treatment.

Diffuse Bone Uptake of 131 I and Effect on Blood Counts in a Patient With Papillary Thyroid Carcinoma and Chronic Lymphocytic Leukemia

ABSTRACT

A 57-year-old woman with history of chronic lymphocytic leukemia was referred to our center for adjuvant 131 I therapy following complete thyroidectomy for differentiated thyroid cancer. Posttherapeutic scintigraphy revealed atypical diffuse osteomedullar uptake. A major drop in lymphocyte count was observed, from 117.7 g/L to 4.8 g/L 8 weeks after 131 I therapy. Bone marrow uptake is presumed to be related to tracer sequestration in leukemic cells. White blood cell count normalization suggests a high sensitivity of leukemic cells to beta emission. This scintigraphic pattern may act as a pitfall for nuclear medicine physician.

The effect of radioiodine therapy on blood cell count in patients with differentiated thyroid cancer

PURPOSE

This study aimed to investigate the long-term effects of radioiodine treatment (RAI) on blood cell counts in patients with differentiated thyroid cancer (DTC) and to describe the characteristics of patients at high risk for blood cell count abnormalities.

METHODS

The study included patients with DTC who underwent RAI treatment between 2007 and 2017. Patients with regular complete blood counts for at least 5 years were included, while those with diseases or treatments that could influence blood count parameters were excluded. Blood cell count abnormalities were defined according to the Common Terminology Criteria for Adverse Events version 5.0, and factors influencing these abnormalities were examined.

RESULTS

A total of 225 patients were analyzed. The mean age at diagnosis was 45.8 ± 13.9 years, and 76.5% of patients were female. In the first year after RAI, leukocyte, neutrophil, and lymphocyte counts were significantly reduced compared with baseline values. The leukocyte and neutrophil counts returned to baseline values by the third year, while the decrease in lymphocytes continued until the fifth year. Blood cell count abnormalities developed in 16 patients (7.1%) within the first year after RAI. Risk factors for blood cell count abnormalities within the first year after RAI included male sex, older age, T4, N1, and M1 disease, as well as higher RAI doses. In logistic regression analysis, only RAI dose remained independently associated with blood cell count abnormalities.

CONCLUSION

These results suggest an association between RAI dose and blood cell count abnormalities, characterized by mild lymphopenia, and indicate that the risk of mild lymphopenia persists over time. Careful consideration should be given when planning high-dose RAI for patients at a high risk of blood cell count abnormalities, such as males with metastatic disease and of advanced age.

Effects of radioactive iodine on clonal hematopoiesis in patients with thyroid cancer: A prospective study

OBJECTIVE

Exposure to therapeutic radioactive iodine (RAI) is associated with an increased relative risk of myeloid malignancies. Clonal hematopoiesis (CH) is a precursor state that can be detected in blood of healthy individuals decades before overt development of leukemia. We prospective studied the effects of RAI on CH.

DESIGN

Prospective cohort study.

PATIENTS AND MEASUREMENTS

We examined the effect of RAI on CH in 20 patients exposed to RAI for thyroid carcinoma and 20 age-matched unexposed controls. CH status was determined at baseline, 6, 12, 18 and 24 months. We also examined the effect of CH on structural progression of disease.

RESULTS

No CH mutations were observed in the patient population that were not present at baseline. Using a variant allelic fraction (VAF) of 2% to define CH, 6/20 older patients (55-80 years old) had CH compared to 2/20 younger patients (20-40 years old) (p = 0.11). Six patients exposed to RAI had CH compared to two patients not exposed to RAI (30% vs. 10%, p = 0.11). There was no significant difference in CH VAF increase in patients treated with RAI compared to untreated age-matched controls (3.8% vs. 1.2%, p = 0.2). CH was significantly associated with somatic BRAFV600E mutations and with worse progression-free survival in the overall cohort as well as among BRAFV600E-mutant tumors.

CONCLUSIONS

There was no increase in CH in patients treated with RAI over a 2-year follow-up period. Larger studies with longer follow-up periods are needed to investigate the association between RAI and clonal dynamics. The presence of CH is associated with worse structural progression in both BRAFV600E-mutant and wild-type thyroid cancers.

Reprogramming of myeloid cells and their progenitors in patients with non-medullary thyroid carcinoma

Myeloid cells, crucial players in antitumoral defense, are affected by tumor-derived factors and treatment. The role of myeloid cells and their progenitors prior to tumor infiltration is poorly understood. Here we show single-cell transcriptomics and functional analyses of the myeloid cell lineage in patients with non-medullary thyroid carcinoma (TC) and multinodular goiter, before and after treatment with radioactive iodine compared to healthy controls. Integrative data analysis indicates that monocytes of TC patients have transcriptional upregulation of antigen presentation, reduced cytokine production capacity, and overproduction of reactive oxygen species. Interestingly, these cancer-related pathological changes are partially removed upon treatment. In bone marrow, TC patients tend to shift from myelopoiesis towards lymphopoiesis, reflected in transcriptional differences. Taken together, distinct transcriptional and functional changes in myeloid cells arise before their infiltration of the tumor and are already initiated in bone marrow, which suggests an active role in forming the tumor immune microenvironment.

Cardiovascular Effects of Cumulative Doses of Radioiodine in Differentiated Thyroid Cancer Patients with Type 2 Diabetes Mellitus

Radioiodine (131I) therapy for differentiated thyroid cancer (DTC) involves exposure of the whole body, including the heart, to ionizing radiation. This exposure to the subsequent risk of heart disease is uncertain, especially in patients with DTC associated with type 2 diabetes mellitus (DTC/+T2DM). The current study aimed to assess the relationship between left ventricular ejection fraction (LVEF), high cumulative 131I dose, and peripheral blood parameters in patients with DTC/−T2DM and DTC/+T2DM. The study enrolled 72 female patients with DTC/−T2DM and 24 with DTC/+T2DM who received cumulative 131I doses above 150 mCi (5.55 GBq). LVEF was lower in patients with concomitant T2DM than those without (p < 0.001). The cumulative 131I dosage was inversely correlated with LVEF only in DTC/−T2DM patients (r = −0.57, p < 0.001). In the DTC/+T2DM group, LVEF was negatively associated with absolute platelet count (r = −0.67, p < 0.001) and platelet-to-lymphocyte ratio (r = −0.76, p < 0.001). Our results demonstrate that exposure to high cumulative 131I doses has different cardiovascular effects in DTC/−T2DM and DTC/+T2DM.

Effect of ¹³¹I Therapy on Complete Blood Count in Patients with Differentiated Thyroid Cancer

Background

The aim of this study was to investigate the effects of ¹³¹I therapy on complete blood count (CBC) in patients with differentiated thyroid cancer (DTC).

Materia/Methods

We analyzed CBC in 542 patients with DTC who were grouped according to treatment cycles and cumulative dose and then subdivided by sex and age. The effects of ¹³¹I therapy among the different groups and subgroups were analyzed.

Results

After sorting patients by treatment cycles and doses, ¹³¹I therapy was found to have different effects on CBC depending on patient sex and age. The effect on white blood cell (WBC) counts persisted longer in women, while increases in hemoglobin (Hb) were more significant in men. The influence on red blood cell (RBC) counts was short-lived in patients aged 45 to 54 years. Monocyte counts were significantly decreased only in patients aged 55 years and older who had undergone 3 or 4 treatment cycles. In men, CBC was more affected by cumulative dose. ¹³¹I therapy only influenced platelet and monocyte counts in patients aged 55 years or older. Hb was significantly decreased and increased in the high- and low-dose groups, respectively. No significant complications were observed during follow-up.

Conclusions

¹³¹I therapy had a greater impact on WBC counts in women, while changes in RBC counts and Hb were more obvious in men. During ¹³¹I therapy, clinicians should pay attention to different CBC indicators based on a patient’s sex and age, but risks associated with an altered CBC are unlikely to outweigh the benefits of ¹³¹I. The results of the present study may help alleviate the concerns of a large proportion of patients with DTC and their families about the effects of ¹³¹I therapy on CBC.

Prognostic value and dynamics of antithyroglobulin antibodies for differentiated thyroid carcinoma

Background: The clinical value of antithyroglobulin antibodies (TgAb) as a tumor marker for differentiated thyroid cancer (DTC) is still controversial. Materials & methods: We studied 110 TgAb positive DTC patients who underwent total thyroidectomy and ¹³¹I therapies. Multivariate logistic regression was conducted to analyze the association between prognostic factors and disease outcomes. Results & conclusion: Pre-ablation TgAb levels and the changes of TgAb in 6-12 months after the first ¹³¹I therapy were risk factors for disease outcome in patients younger than 55, while extrathyroid extension was a risk factor in patients older than 55. The median TgAb half-life was 7.7 months and the median time for TgAb positivity to become negative was 15.8 months. The dynamics of TgAb within the first year after remnant ablation could predict disease outcome for DTC patients.

Hemorheology and oxidative stress in patients with differentiated thyroid cancer following I-131 ablation/metastasis treatment

BACKGROUND

Although radioiodine theraphy (RAIT) is thought to affect blood cells and oxidative stress, hemorheological alterations following dose-dependent RAIT remains unknown.

OBJECTIVE

The aim of this study was to determine the effects of RAIT on hemorheological and oxidative stress parameters in patients with differentiated thyroid cancers (DTC).

METHODS

Totally 31 DTC patients (mean age 46.32±11.15 years) and 26 healthy controls (mean age 50.50±6.22 years) were included. Venous blood samples were collected from each patient before and after treatment (7th day, 1th month and 6th month). Erythrocyte aggregation-deformability and oxidative stress parameters were determined. p < 0.05 was considered as statistically significant.

RESULTS

Erythrocyte deformability of the patients determined at 16.87 and 30 Pascal were significantly lower than healthy individuals. Erythrocyte aggregation index (AI) of the patients was higher, whereas erythrocyte aggregation half-time (t½) was lower compared to control. Erythrocyte deformability values and AI were not significantly different from the pre- and post-radioiodine treatment groups. There was no statistically significant difference between the oxidative stress parameters before and after the treatment.

CONCLUSIONS

Patients were in a worse hemorheological condition compared to healthy individuals. After RAIT, RBC deformability and aggregation were not affected and no significant change in oxidative stress parameters was detected.

Radioprotective effect of vitamin E on salivary glands after radioiodine therapy for differentiated thyroid cancer: a randomized-controlled trial

OBJECTIVES

This study aimed to examine the radioprotective effect of vitamin E on salivary glands after radioactive iodine (I) therapy in patients with differentiated thyroid cancer.

PATIENTS AND METHODS

Eighty-two patients with differentiated thyroid cancer were enrolled in this study. They were divided randomly into four groups (control group: 22 cases, group A: 23 cases, group B: 22 cases, and group C: 15 cases) before postsurgical ablation therapy with 100 mCi I. The patients in groups A, B, and C received vitamin E 100, 200, and 300 mg/day orally, respectively, for a duration of 1 week before to 4 weeks after I therapy. Salivary gland function was assessed using salivary gland scintigraphy immediately before and 6 months after I therapy. Uptake fraction (UF), uptake index (UI), excretion fraction (EF), and excretion ratio (ER) of each salivary gland were measured and compared.

RESULTS

On comparison between before and after I therapy in the control group, there was a significant decrease in UF of both right and left parotid glands (all P<0.01). In group A, a significant increase in EF of the right parotid gland (P<0.01) and UI of the right submandibular gland (P<0.05) was found. In group B, there was a significant increase in UI of the right parotid gland and both submandibular glands (all P<0.01). In group C, there was a significant increase in UF of the left parotid gland (P<0.05) and the right submandibular gland (P<0.01). Also, there was a statistical increase in UI in both submandibular glands (all P<0.01). However, on comparing the changes in the post-I therapy salivary scintigraphy parameters among the four groups, there was a significant difference in ΔUI of the right parotid gland (P<0.05) and both submandibular glands (all P<0.01), as well as ΔER of the left parotid gland (P<0.05) and ΔUF of the left submandibular gland (P<0.05).

CONCLUSION

Vitamin E exerts significant protective effects on the parotid and submandibular glands after I therapy.

Effects of first radioiodine ablation on functions of salivary glands in patients with differentiated thyroid cancer

The aim of this study was to evaluate the effects of the first radioactive iodine (I) therapy on functions of salivary glands in patients with differentiated thyroid carcinoma (DTC).There were 36 consented patients with DTC enrolled in this study, who received 3.7 GBq (100mCi) I for ablation after total thyroidectomy. Salivary gland function was assessed using salivary gland scintigraphy in two phases, one 4 hours before and the other 6 months after I therapy (both under thyrotropin stimulation condition). Quantitative parameters including uptake fraction (UF), uptake index (UI), excretion fraction (EF), and excretion ratio (ER) were measured and compared. Blood parameters were also compared. Associations between sex and outcome of the first I therapy as well as individual salivary gland function were measured. Wilcoxon Signed Rank Sum test and χ test were used for statistical analysis.When compared between pre-ablation and post-ablation, UF of bilateral parotid and submandibular glands were significantly increased (all P < .01). UI of both submandibular glands were significantly increased (P < .05). This seemingly increased uptake function after the first I therapy was actually compensatory mechanism of salivary gland, which indicated a possible intermediate state after radiation. But salivary glands' secretory function had not changed significantly except for left submandibular gland; we demonstrated that only left submandibular gland showed significantly decreased ER (P < .05). Thyroglobulin and thyroglobulin antibody significantly decreased after I therapy (P < .05). There were no sex differences on therapeutic outcome and salivary gland dysfunctions after the first I therapy. Salivary gland of both males and females could be affected by I therapy.The first I ablative therapy may impair the salivary uptake and secretory function of patients with DTC. There was no association between sex and salivary gland dysfunction.