Effects of I-131 therapy on gonads and pregnancy outcome in patients with thyroid cancer

The Future Direction of Women in Nuclear Medicine and Nuclear Medicine in Women's Health

This work discusses the role of Nuclear Medicine for women's health, the role of women in the development of this emerging field and the various issues which arise from both. It emphasizes the importance of young women and their competing needs due to factors like pregnancy and work-related challenges. The objectives of this overview include improving imaging techniques, preserving fertility during cancer treatment, diagnosing pelvic and uterine conditions, developing radiopharmaceuticals for women's health, protecting female employees in Nuclear Medicine, and considering the role of artificial intelligence.

Female Papillary Thyroid Cancer Survivors Are at Increased Risk of Adenomyosis and Endometrial Hyperplasia

PURPOSE

Thyroid cancer (TC) is the most common endocrine cancer worldwide, affecting mainly women of reproductive age. However, no data exist about its association with endometrial or uterine disorders. This study aimed to assess the risk of hyperproliferative pathology of the reproductive system in female ТС survivors.

METHODS

This was a cross-sectional study of female patients aged 20-45 years diagnosed with papillary TC (PTC) from 1994-2018. Age-matched females with normal thyroid structures served as controls.

RESULTS

One hundred and sixteen patients (mean age 36.7±61 years) and 90 age-matched controls were included. PTC survivors demonstrated an increased risk for adenomyosis [odds ratio (OR) 2.5, 95% confidence interval (CI) 1.3-4.8] and endometrial hyperplasia (OR 3.9, 95% CI 1.1-14.3), compared with controls. The risk for adenomyosis was higher after the ten post-operative years (OR 5.3, 95% CI 2.29- 12.05) than during the first 5-10 years (OR 2.3, 95% CI 1.02-5.10) and increased with the number of RAI courses and the degree of TSH suppression. The risk of endometrial hyperplasia was most evident during the first five years post-thyroidectomy (OR 6.0, 95% CI 1.4-25.5), especially in patients with TSH <0.1 mU/L (OR 6.8, 95% CI 1.4-33.28) No difference in uterine leiomyomas or endometrial polyps was found between PTC survivors and controls.

CONCLUSIONS

Female PTC survivors are at increased risk of endometrial hyperplasia and adenomyosis compared with those with normal thyroid structures.

The effect of I-131 therapy on pregnancy outcomes after thyroidectomy in patients with differentiated thyroid carcinoma: a meta-analysis

PURPOSE

Studies on the effects of I-131 therapy on pregnancy outcomes after differentiated thyroid carcinoma (DTC) surgery showed inconsistent findings. The purpose of the study was to investigate the association between I-131 therapy and pregnancy outcomes in female DTC patients.

METHODS

PubMed, Embase, Cochrane Library, CNKI, and VIP were searched until November, 2020. Keywords included differentiated thyroid cancer, thyroid carcinoma, thyroid neoplasm, radioiodine, I-131, ¹³¹I, pregnancy outcomes, reproduction, fertility, abortion, preterm birth, and congenital malformation. Studies that provided the pregnancy outcomes in DTC patients who received I-131 therapy and those who did not receive I-131 therapy were included. Meta-analysis was performed in Stata/SE 12. A random or fixed effects model was adopted according to the result of heterogeneity test.

RESULTS

Seven observational studies were eligible, involving 125,591 participants and 13,811 pregnancies. It showed that postoperative I-131 therapy for DTC had no significant effect on spontaneous abortion (OR = 1.05, P = 0.701), induced abortion (OR = 1.06, P = 0.859), abortion (OR = 1.07, P = 0.098), premature birth (OR = 1.02, P = 0.756), stillbirth (OR = 1.58, P = 0.364), and congenital malformation(OR = 1.00, P = 0.986). Cumulative RAI dose >3.7 GBq or <3.7 GBq had no significant effect on abortion (OR = 0.94, P = 0.252) and congenital malformation (OR = 1.05, P = 0.752).The group in which interval time between last I-131 therapy and pregnancy >1 year had significant lower risk of abortion than with interval <1 year (OR = 0.60, P = 0.000).

CONCLUSIONS

Pregnancy is not recommended for DTC patients within 1 year after I-131 therapy.

Decline in anti-Müllerian hormone concentrations following radioactive iodine treatment in women with differentiated thyroid cancer: A systematic review and meta-analysis

AIM

Radioactive iodine (RAI) is frequently used as adjuvant therapy in patients with differentiated thyroid cancer (DTC). However, its effect on ovarian reserve has not been fully elucidated, with studies yielding inconsistent results. The aim of this study was to systematically review and meta-analyze the best available evidence regarding the effect of RAI on ovarian reserve in premenopausal women with DTC.

METHODS

A comprehensive literature search was conducted in PubMed, Cochrane and Scopus, through to December 6^th, 2020. Data were expressed as weighted mean difference (WMD) with a 95% confidence interval (CI). The I² index was used to assess heterogeneity.

RESULTS

Four prospective studies were included in the qualitative and quantitative analysis. Anti-Müllerian hormone (AMH) concentrations decreased at three (WMD -1.66 ng/ml, 95% CI -2.42 to -0.91, p<0.0001; I² 0%), six (WMD -1.58, 95% CI -2.63 to -0.52, p=0.003; I² 54.7%) and 12 months (WMD -1.62 ng/ml, 95% CI -2.02 to -1.22, p<0.0001; I² 15.5%) following a single RAI dose compared with baseline (three studies; n=104). With respect to follicle-stimulating hormone (FSH) concentrations, no difference was observed at six (WMD +3.29 IU/l, 95% CI -1.12 to 7.70, p=0.14; I² 96.8%) and 12 months (WMD +0.13 IU/l, 95% CI -1.06 to 1.32, p=0.83; I² 55.2%) post-RAI compared with baseline (two studies; n=83). No data were available for antral follicle count.

CONCLUSIONS

AMH concentrations are decreased at three months and remain low at 6 and 12 months following RAI treatment in women with DTC. No difference in FSH concentrations post-RAI is observed.

The Effect of Radioactive Iodine Therapy on Ovarian Function and Fertility in Female Thyroid Cancer Patients: A Systematic Review and Meta-Analysis

Introduction: Thyroid cancer is one of the most common carcinomas diagnosed in adolescents and young adults, with a rapidly rising incidence for the past three decades. Surgery is the standard treatment for patients with differentiated thyroid carcinoma (DTC), and when indicated, followed by radioactive iodine (RAI) treatment. The aim of this study was to evaluate the possible effects of RAI therapy on ovarian function and fertility in women. Methods: The PubMed, Embase, and Web of Science databases were systematically searched up to January 2020. In addition, a meta-analyses were performed for anti-Mullerian hormone (AMH) levels after RAI, comparison of AMH levels prior and 1 year after RAI, and pregnancy rates in patient with thyroid cancer receiving RAI compared with patients with thyroid cancer who did not receive RAI. Results: A total of 36 studies were eligible for full-text screening and 22 studies were included. The majority of the studies had a retrospective design. Menstrual irregularities were present in the first year after RAI in 12% and up to 31% of the patients. Approximately 8-16% of the patients experienced amenorrhea in the first year after RAI. Women who received RAI treatment (median dose 3700 MBq [range 1110-40,700 MBq]); had menopause at a slightly younger age compared with women who did not receive RAI treatment, 49.5 and 51 years, respectively (p < 0.001). Pooled AMH of the seven studies reporting AMH concentrations after RAI was 1.79 ng/mL. Of these, four studies reported AMH concentrations prior and 1 year after RAI. The mean difference was 1.50 ng/mL, which was significant. Finally, meta-analysis showed that patients undergoing RAI were not at a decreased risk of becoming pregnant. Conclusions: Most of the studies indicate that RAI therapy for DTC is not associated with a long-term decrease in pregnancy rates although meta-analyses show a significant decrease in AMH levels after RAI therapy. Prospective studies are needed to confirm these results. We recommend counseling patients about the possible effects of ¹³¹I and incorporate today's knowledge in multidisciplinary counseling.

Impact of pregnancy on papillary thyroid carcinoma prognosis

Introduction

thyroid carcinoma is more frequent in women of reproductive age. It can affect both fertility and the course of pregnancy. The aim of the study was to investigate the influence of pregnancy as a factor of recurrence or progression, on the prognosis of thyroid carcinoma.

Methods

we conducted a retrospective cohort study of 117 young female patients followed up for papillary thyroid carcinoma (PTC) at the Department of Endocrinology, Diabetology and Metabolic Diseases of Ibn Rochd University Hospital of Casablanca, from January 2010 to December 2018, divided into 2 groups: group 1 composed of pregnant patients (n=42) and group 2 being the control group (n=75). Statistical analysis was made using SPSS software version 22.0.0.

Results

average age of pregnant patients was 35 ± 6.5 years old. Mean duration between first pregnancy and treatment completion was 4.4 ± 3.1 years. Over an average treatment duration of 14.4 months in postpartum, 30 patients were in remission (thyroglobulin (Tg) <1μg/l, negative thyroglobulin antibody and no morphological abnormality), while 12 had persistent symptoms (detectable Tg/thyroglobulin antibody and/or morphological abnormality). Thyroid stimulating hormone (TSH) during pregnancy was on average 0.83 mIU/l. Cancer progression was correlated with persistence of thyroid cancer to treatment before pregnancy (p = 0.01), pre-existing distant or locoregional metastases (p = 0.02) and delayed administration of radio-iodine therapy (p = 0.01). Interval between diagnosis and pregnancy, TSH level during pregnancy or the pre-conception thyroglobulin level did not have a statistically significant impact. Pregnancy was not associated with progression or recurrence of thyroid cancer (adjusted risk ratio 1.04, 95% confidence interval 0.91-1.32).

Conclusion

this study shows that pregnancy has no impact on recurrence or progression of thyroid cancer in patients declared in remission prior to conception.

A narrative review of pregnancy after malignancies in young women that don't originate in the female genital organs or in the breast

While cancer during pregnancy and its treatment has grown to be a popular topic in recent years, little is known on how to advise patients looking to conceive or conceiving after cancer treatment. The aim of this paper is to review the available literature on the impact of pregnancy on survivors of the most common childhood cancers, brain cancer, haematological malignancies, thyroid cancer, melanomas and sarcomas. Its main objective is to be a source of information for clinicians looking to counsel patients in these delicate moments exploiting all the available literature, albeit scarce. Given the available literature, we conclude that the presence of a multidisciplinary team is of great importance in supporting the patient and her loved ones when facing pregnancy with a previous cancer diagnosis.

Improved Noninvasive In Vivo Tracking of AAV-9 Gene Therapy Using the Perchlorate-Resistant Sodium Iodide Symporter from Minke Whale

The sodium iodide symporter (NIS) is widely used as a reporter gene to noninvasively monitor the biodistribution and durability of vector-mediated gene expression via gamma scintigraphy, single-photon emission computed tomography (SPECT), and positron-emission tomography (PET). However, the approach is limited by background signal due to radiotracer uptake by endogenous NIS-expressing tissues. In this study, using the SPECT tracer pertechnetate (^99mTcO₄) and the PET tracer tetrafluoroborate (B¹⁸F₄), in combination with the NIS inhibitor perchlorate, we compared the transport properties of human NIS and minke whale (Balaenoptera acutorostrata scammoni) NIS in vitro and in vivo. Based on its relative resistance to perchlorate, the NIS protein from minke whale appeared to be the superior candidate reporter gene. SPECT and PET imaging studies in nude mice challenged with NIS-encoding adeno-associated virus (AAV)-9 vectors confirmed that minke whale NIS, in contrast to human and endogenous mouse NIS, continues to function as a reliable reporter even when background radiotracer uptake by endogenous NIS is blocked by perchlorate.

Long-Term Effects of Radioiodine Treatment on Female Fertility in Survivors of Childhood Differentiated Thyroid Carcinoma

Background: Differentiated thyroid carcinoma (DTC) during childhood is a rare disease. Its excellent survival rate requires a focus on possible long-term adverse effects. This study aimed to evaluate fertility in female survivors of childhood DTC by assessing various reproductive characteristics combined with anti-Müllerian hormone (AMH) levels (a marker of ovarian reserve). Methods: Female survivors of childhood DTC, diagnosed at ≤18 years of age between 1970 and 2013, were included. Survivors were excluded when follow-up time was less than five years or if they developed other malignancies before or after diagnosis of DTC. Survivors filled out a questionnaire regarding reproductive characteristics (e.g., age at menarche and menopause, pregnancies, pregnancy outcomes, need for assisted reproductive therapy). Survivors aged <18 years during evaluation received an altered questionnaire without questions regarding pregnancy and pregnancy outcomes. These data were combined with information from medical records. AMH levels were measured in serum samples and were compared with AMH levels from 420 women not treated for cancer. Results: Fifty-six survivors with a median age of 31.0 (interquartile range, IQR, 25.1-39.6) years were evaluated after a median follow-up of 15.4 (IQR 8.3-24.7) years. The median cumulative dose of ¹³¹I administered was 7.4 (IQR 3.7-13.0) GBq/200.0 (IQR 100.0-350.0) mCi. Twenty-five of the 55 survivors aged 18 years or older during evaluation reported 64 pregnancies, 45 of which resulted in live birth. Of these 55, 10.9% visited a fertility clinic. None of the survivors reported premature menopause. Age at AMH evaluation did not differ between DTC survivors and the comparison group (p = 0.268). Median AMH levels did not differ between DTC survivors and the comparison group [2.0 (IQR 1.0-3.7) μg/L vs. 1.6 (IQR 0.6-3.1) μg/L, respectively, p = 0.244]. The cumulative dose of ¹³¹I was not associated with AMH levels in DTC survivors (r_s = 0.210, p = 0.130). Conclusions: Female survivors of DTC who received ¹³¹I treatment during childhood do not appear to have major abnormalities in reproductive characteristics nor in predictors of ovarian failure.

Thyroid nodules and cancer during pregnancy, post-partum and preconception planning: Addressing the uncertainties and challenges

Thyroid nodules and thyroid cancer have become increasingly common worldwide. When discovered during pregnancy, they pose unique diagnostic and therapeutic challenges for both the treating physician and the patient. The benefits of treatment should be carefully weighed against risks that may adversely impact maternal and fetal health. In this review, we present current knowledge and controversies surrounding the management of thyroid nodules and thyroid cancer in pregnancy, in the post-partum period and during preconception planning.

Inter-species variation in monovalent anion substrate selectivity and inhibitor sensitivity in the sodium iodide symporter (NIS)

The sodium iodide symporter (NIS) transports iodide, which is necessary for thyroid hormone production. NIS also transports other monovalent anions such as tetrafluoroborate (BF4-), pertechnetate (TcO4-), and thiocyanate (SCN-), and is competitively inhibited by perchlorate (ClO4-). However, the mechanisms of substrate selectivity and inhibitor sensitivity are poorly understood. Here, a comparative approach was taken to determine whether naturally evolved NIS proteins exhibit variability in their substrate transport properties. The NIS proteins of thirteen animal species were initially assessed, and three species from environments with differing iodide availability, freshwater species Danio rerio (zebrafish), saltwater species Balaenoptera acutorostrata scammoni (minke whale), and non-aquatic mammalian species Homo sapiens (human) were studied in detail. NIS genes from each of these species were lentivirally transduced into HeLa cells, which were then characterized using radioisotope uptake assays, 125I- competitive substrate uptake assays, and kinetic assays. Homology models of human, minke whale and zebrafish NIS were used to evaluate sequence-dependent impact on the organization of Na+ and I- binding pockets. Whereas each of the three proteins that were analyzed in detail concentrated iodide to a similar degree, their sensitivity to perchlorate inhibition varied significantly: minke whale NIS was the least impacted by perchlorate inhibition (IC50 = 4.599 μM), zebrafish NIS was highly sensitive (IC50 = 0.081 μM), and human NIS showed intermediate sensitivity (IC50 = 1.566 μM). Further studies with fifteen additional substrates and inhibitors revealed similar patterns of iodide uptake inhibition, though the degree of 125I- uptake inhibition varied with each compound. Kinetic analysis revealed whale NIS had the lowest Km-I and the highest Vmax-I. Conversely, zebrafish NIS had the highest Km and lowest Vmax. Again, human NIS was intermediate. Molecular modeling revealed a high degree of conservation in the putative ion binding pockets of NIS proteins from different species, which suggests the residues responsible for the observed differences in substrate selectivity lie elsewhere in the protein. Ongoing studies are focusing on residues in the extracellular loops of NIS as determinants of anion specificity. These data demonstrate significant transport differences between the NIS proteins of different species, which may be influenced by the unique physiological needs of each organism. Our results also identify naturally-existing NIS proteins with significant variability in substrate transport kinetics and inhibitor sensitivity, which suggest that the affinity and selectivity of NIS for certain substrates can be altered for biotechnological and clinical applications. Further examination of interspecies differences may improve understanding of the substrate transport mechanism.

Reproductive and gynecological complication risks among thyroid cancer survivors

PURPOSE

Thyroid cancer is the most rapidly increasing cancer in the USA, affects a young, mostly female population, and has high survival. The aim of this study was to determine if there is an increased risk of reproductive system adverse events or pregnancy complications among women diagnosed with thyroid cancer under the age of 50.

METHODS

Up to five female cancer-free individuals were matched to each female thyroid cancer survivor diagnosed before the age of 50 based on birth year, birth state, and follow-up time, within the Utah Population Database. Medical records were used to identify disease diagnoses stratified over three time periods: 0-1, > 1-5, and > 5-10 years after cancer diagnosis. Cox proportional hazards models were used to estimate hazard ratios (HR) with adjustment on matching factors, race, BMI, and Charlson Comorbidity Index.

RESULTS

There were 1832 thyroid cancer survivors and 7921 matched individuals. Thyroid cancer survivors had higher rates of having multiple health conditions associated with the gynecological system (15.4% vs. 9.4%) and pregnancy (14.3% vs 9.5%) > 1-5 years after cancer diagnosis. Increased risks persisted > 5-10 years after cancer diagnosis for menopausal disorders (HR = 1.78, 99% CI = 1.37, 2.33) and complications related to pregnancy (HR = 2.13, 99% CI = 1.14, 3.98). Stratified analyses showed these risks remained increased across different treatment types.

CONCLUSIONS

There were significant risk increases in reproductive system and pregnancy complications among female thyroid cancer survivors within this study.

IMPLICATIONS FOR CANCER SURVIVORS

Although radiation has been linked to reproductive risks in previous studies, we found risks were increased in patients regardless of treatment.

Pregnancy in papillary thyroid cancer survivors

OBJECTIVE

To evaluate “papillary thyroid carcinoma-pregnancy” interaction among cancer survivors.

MATERIAL AND METHODS

The clinical records of 8 pregnant women who received treatment for papillary thyroid cancer before their pregnancy were evaluated. Clinical features, pregnancy/perinatal outcomes and high-risk factors were compared with 45 controls who were randomly assigned from the institutional perinatal medicine database.

RESULTS

Patients in the cancer group were older than the control group (34.3 vs 29.8 years). The cesarean section rate was higher (62.5% vs 33.3%) and the APGAR scores at the 1^st and 5^th minutes were lower in the cancer group.

CONCLUSION

Management of pregnancies with papillary thyroid cancer treatment and follow-up requires a multidisciplinary approach with careful antenatal care and perinatal surveillance. Patients who have received papillary thyroid cancer treatment can safely undergo pregnancy.

The preliminary clinical observation and analysis of childbearingage women with a history of iodine-131 treatment for Graves' disease

Whether radioactive iodine treatment of Graves' disease (GD) during pregnancy will increase pregnancy loss and affect fetal development is still a matter of concern. From May 2005 to December 2015, 2,276 childbearing-age women with GD received iodine-131 treatment in our departments and were retrospectively enrolled in our study. When some of them were found to have been pregnant, their thyroid functions were measured every 4 weeks, in addition, thyroid-stimulating hormone (TSH) was measured 6 weeks after delivery. When necessary, levothyroxine or propylthiouracil (PTU) was given in order to control their TSH levels during pregnancy. Finally, 69 pregnant women (29 ± 3.5 years old) and 1346 women who were not pregnant during the follow-up period were enrolled into this study. They were all hyperthyroid before or during pregnancy. Among 69 pregnant women, the administrated amount of iodine-131 was 254.9 ± 99.9 MBq. Fifty patients became subclinically hypothyroid after treatment and were administrated levothyroxine (55 ± 25 μg/d). Seven patients were diagnosed with subclinical hyperthyroidism during pregnancy and they received PTU (25 ± 12.5 mg/d). Twelve patients with normal thyroid function were also clinically followed. Among 69 women, 63 had a single birth, 3 had dizygotic twins, 2 had two pregnancies and 1 had a single twin birth. Sixty five babies were born full-term, while 9 were premature (4 ± 1 weeks early) with birth weight 3.2 ± 0.5 kg. Six new born babies were considered to be low birth weight infants (< 2.5 kg) while 5 were high birth weight (> 4 kg), but the weights of all the infants were within the normal range. During the period of observation to December 2015, all the infants were found to grow and develop normally. Among 1346 women who were not pregnant were in the further follow-up. Our study found no detrimental effects of the iodine-131 treatment in the pregnant women or their offspring so far.

Pregnancy Incidence in Female Nasopharyngeal Carcinoma Survivors of Reproductive Age: A Population-Based Study

This study evaluated the pregnancy incidence in female nasopharyngeal carcinoma (NPC) survivors of reproductive age.In a nationwide cohort, 2816 female patients 15 to 50 years of age from 1998 to 2010 were identified from the Taiwan National Health Insurance Research database. Comorbidities, complications during pregnancy, and delivery status were recorded. All patients were followed up until a diagnosis of pregnancy, withdrawal from the National Health Insurance system, or December 31, 2011.Overall, 155 patients (incidence rate [IR] = 9.50) were pregnant in the NPC group, whereas 251 patients (IR = 12.80) were pregnant in the non-NPC group. The cumulative incidence of pregnancy in the NPC group was lower than that in the non-NPC group (incidence rate ratio = 0.74, 95% CI = 0.61-0.91). The adjusted hazard ratio of pregnancy in the NPC group was 0.79 with 95% CI = 0.61-0.96, compared with the non-NPC group.The incidence of pregnancy is significantly lower among female NPC survivors of reproductive age than among those without NPC.

Pregnancy Outcome After I-131 Therapy for Patients With Thyroid Cancer: A Nationwide Population-Based Cohort Study

The aim of this study was to evaluate the influence of I-131 therapy on pregnancy outcome in patients that received therapeutic I-131 doses for thyroid cancer in Taiwan.This nationwide population-based cohort study was based on data from 1998 to 2010 obtained from the Taiwanese National Health Insurance Research Database. We identified 11,708 women with thyroid cancer (≥ 15 and ≤ 50 years of age) by International Classification of Diseases, Ninth Revision, Clinical Modification codes. Patients were divided into 2 cohorts: I-131 therapy cohort and non-I-131 therapy cohort. The mean follow-up period was 6.08 years for the I-131 cohort and 6.87 years for the non-I-131 cohort. The case cohort and the control cohort comprised 775 and 716 pregnant patients, respectively.The overall incidence of pregnancy was significantly lower in the I-131 cohort (adjusted HR = 0.77, 95% CI = 0.70-0.86) and it was also observed when the patients were stratified according to age (HR = 0.73, 95% CI = 0.64-0.83 in 25-34 years; HR = 0.63, 95% CI = 0.49-0.82 in 35-44 years). Patients in the I-131 cohort had a lower successful delivery rate, particularly among patients in 25 to 34 years (OR = 0.60, 95% CI = 0.45-0.80). No significant difference was observed for adverse pregnancy conditions between 2 cohorts.I-131 therapy is associated with decreased pregnancy and successful delivery rates. The underlying mechanism likely involves physician recommendation, patient's psychological issue, and potential impact of I-131 treatment on reproductive health. Further investigation is needed.

In Vivo Delivery of Tinospora cordifolia Root Extract Preventing Radiation-Induced Dystrophies in Mice Ovaries

Unconscious and unplanned radiation exposures are a severe threat to gonads particularly ovaries. The present study aims at finding radioprotective effect of Tinospora cordifolia (Willd.) Miers root extract (TCRE) in ovaries. Swiss albino mice were divided into four groups: Group 1 served as “normal” and is administered double distilled water and Group 2 is given TCRE with optimum dosage selected as 75 mg/mice. Group 3 serving the purpose of “irradiated control” were exposed to 2.5 Gy gamma radiation. Group 4 (experimental) were administered optimum dosage of TCRE with prior exposure to 2.5 Gy gamma radiation. Follicle cell counts were scored at autopsy intervals of 24 hrs, 3 days, 7 days, 15 days, and 30 days after gamma irradiation. To understand the mechanism of radioprotection, lipid peroxidation (LPO) and glutathione (GSH) levels were also measured in all groups. TCRE supplementation rendered significant protection to ovaries by restoring follicle counts; it also reduced LPO levels and increased GSH levels in ovaries. It implies that TCRE administration protects ovaries against radiation exposure.

Thyroid disorders during pregnancy

Thyroid disorders are common in pregnancy and in nonpregnant women of childbearing age, but can be missed because of nonspecific symptoms and normal changes in thyroid gland physiology during pregnancy. The prevalence of overt hyperthyroidism complicating pregnancy has been reported to range between 0.4% and 1.7%, and an estimated 2% to 3% of women are hypothyroid during pregnancy. Abnormalities in maternal thyroid function are associated with complications during pregnancy, and may affect maternal and fetal outcomes. Thus it is important to identify thyroid disorders before pregnancy or early in pregnancy so that appropriate treatment can be initiated.

Infant's bilobar thyroid agenesis and mother's I-131 accidental administration

Bilobar thyroid agenesis is one of rare diseases. Genetic and environmental factors may associate with bilobar thyroid agenesis. But the mechanism is still not completely understood. It had been showed that I-131 administration during pregnancy may induce thyroid dysfunction in newborn. Here we reported a case of female hospital staff who received I-131 accidently during (10-12th gestational weeks) and after her pregnancy. The absorbed dose to fetus was higher than 30mGy. At birth, the infant was found to have no thyroid. It was speculated that the fetal thyroid agenesis may be related with mother' I-131 administration during pregnancy. In addition, this case report also indicated that the radiation dose should be minimized to any developing embryo.

Differential expression patterns of estrogen receptor (ER)-β splice variants between papillary thyroid cancer and nodular thyroid goiter

Background

The aim of this study was to investigate the expression patterns of estrogen receptor (ER) β1 (wild-type ERβ) and ERβ2 (ERβcx) in papillary thyroid cancer (PTC) and nodular thyroid goiter (NTG), and to explore the reasons for the higher incidence of PTC in women of reproductive age.

Material/Methods

ERβ1 and ERβ2 expression was examined immunohistochemically on paraffin-embedded thyroid tissues from 106 patients with PTC and 30 patients with NTG.

Results

There was significant difference in the subcellular localization of ERβ1 (P<0.001), but not in the positive percentage, between PTC and NTG specimens. No significant difference was found in the positive percentage or the subcellular distribution of ERβ2 expression between PTC and NTG specimens. Both nuclear and nucleocytoplasmic ERβ1 expressions were significantly lower in PTC lesions than in NTG tissue (P<0.001 and P<0.05, respectively), while ERβ2 expression was significantly higher in the former than the latter (P<0.05). ERβ1 expression in reproductive-aged (18~45 years) female patients with PTC was lower than that in age-matched male patients (P<0.05), while ERβ2 expression had the opposite expression profile (P<0.05). There was no significant difference in ERβ1 and ERβ2 expression between reproductive-aged and advanced reproductive-aged (>45 years) female patients with PTC.

Conclusions

This preliminary study indicates that the expression patterns of ERβ1 and ERβ2 differ between malignant PTC lesions and benign NTG tissue, and their expression might be involved in the female predominance of PTC during the reproductive years. The clinical and biological significance of these results await further investigation.

Thyroid disorders during pregnancy

Thyroid disorders are common in women during pregnancy. If left untreated, both hypothyroidism and hyperthyroidism are associated with adverse effects on pregnancy and fetal outcomes. It is important to correctly identify these disorders and treat them appropriately to prevent pregnancy-related complications. Levothyroxine is the indicated treatment for hypothyroidism, and thionamides are the treatment of choice for hyperthyroidism; thyroidectomy may be indicated in select cases. When thyroid cancer is diagnosed during pregnancy, a decision must be made regarding performing thyroidectomy during the pregnancy or postponing surgical resection until the postpartum period. Radioactive iodine is absolutely contraindicated during pregnancy and lactation.

Endocrine oncology in pregnancy

Endocrine tumours occur rarely in pregnant women but present clinicians with unique challenges. A high index of suspicion is often required to make a diagnosis since the symptoms and signs associated with many of these tumours, including insulinoma, adrenocortical carcinoma and phaeochromocytoma, mimic those of normal pregnancy or its complications, such as pre-eclampsia. The evidence base which informs management is very limited hence decisions on investigation and therapy must be individualised and undertaken jointly by the multidisciplinary medical team and the patient. The optimal strategy will depend on the nature and stage of the endocrine tumour, gestational stage, treatments available and patient wishes. Thus, surgical intervention, appropriately timed, may be considered in pregnancy for resectable adrenocortical carcinoma or phaeochromocytoma, but delayed until the postpartum period for well-differentiated thyroid cancer. Medical therapy may be required to reduce the drive to tumour growth, control symptoms of hormone excess and to minimise the risks of surgery, anaesthesia or labour.