Female Reproductive Factors and Differentiated Thyroid Cancer

Breast cancer and neoplasms of the thyroid gland: a bidirectional two-sample Mendelian randomization study

Background

With the rising incidence of breast cancer (BC) and neoplasms of the thyroid gland, a potential link between the two has drawn increasing attention. However, the causal relationship remains unclear due to various confounding factors. This study aims to investigate the causality between BC and thyroid tumors using Mendelian Randomization (MR) analysis.

Methods

We conducted a bidirectional two-sample MR analysis, utilizing breast cancer-associated single nucleotide polymorphisms (SNPs) from the Breast Cancer Association Consortium (BCAC) and thyroid tumor-related SNPs from the FinnGen (https://www.finngen.fi/) database. First, we performed univariable MR (UVMR) to assess the causal relationship between BC and both malignant and benign thyroid tumors, followed by reverse causality analysis. To account for potential confounders, we applied multivariable MR (MVMR). The inverse-variance weighted (IVW) method was primarily used, with secondary analyses performed using the weighted median and MR-Egger regression approaches.

Results

UVMR analysis revealed a significant positive causal relationship between BC and malignant thyroid tumors (odds ratio [OR] and 95% confidence interval [CI]: 1.291, 1.143-1.458, P = 3.90×10-5). No causal relationship was found between BC and benign thyroid tumors. The MVMR analysis, adjusting for confounding factors such as smoking, drinking, and body mass index (BMI), confirmed the robustness of the results.

Conclusion

This study provides genetic evidence supporting a causal relationship between BC and malignant thyroid tumors. These findings highlight the importance of thyroid cancer screening in BC patients. However, further MR studies or randomized controlled trials (RCTs) are necessary to assess small effects accurately.

Australian males and females have similar rates of presentation for symptomatic and advanced thyroid cancer: Retrospective analysis of the Australian New Zealand Thyroid Cancer Registry

INTRODUCTION

Thyroid cancer is more commonly diagnosed in females, however recent research has challenged whether this finding is due to a true difference in biology or rates of diagnosis, with concerns that over-diagnosis may be a factor in differences. The rates of symptomatic versus incidental diagnosis by males and females is not well known. This study used the Australian and New Zealand Thyroid Cancer Registry (ANZTCR) to explore whether symptomatic presentation varies between sexes.

MATERIALS AND METHODS

Retrospective analysis on ANZTCR data between 2017 and 2022 was performed. Symptomatic cases were those with thyroid compressing symptoms, toxic goiter, Graves' disease, or abnormal laryngoscopy. Cases with asymptomatic goiter or surgeries for a thyroid nodule were classified as incidental.

RESULTS

Among 1082 patients with differentiated thyroid cancer, 32% of males and 38% of females presented with symptomatic thyroid disease (p = 0.06). A similar rate of presentation of advanced thyroid cancer (T3/4) was seen with male and female patients (n = 70, 47% vs. n = 79, 53%). Females exhibited a higher prevalence of low-risk relapse cancers according to American Thyroid Association stratification (66.3% vs. 50.4%), whereas males exhibited a higher prevalence of high-risk relapse cancers compared to females (27.3% vs. 15.3%, p < 0.001). Regression showed symptoms were associated with more advanced T stage (OR = 1.62, p = 0.02).

DISCUSSION

Symptomatic presentation was similar between males and females, but symptomatic presentation was associated with larger cancers.

CONCLUSION

This study highlights comparable rates of symptomatic detection between males and females with DTCs and symptomatic presentations were responsible for less than 40% of presentations.

Epidemiologic changes in thyroid disease

PURPOSE OF REVIEW

To analyze the evolving epidemiologic trends in thyroid disease, focusing on risk factors, underlying drivers of these changes, and their implications on clinical practice and research priorities.

RECENT FINDINGS

Thyroid disease remains one of the most prevalent groups of disorders globally, and the shift in its frequency and distribution is multifactorial. The prevalence of hypothyroidism increases with age, although normal thyrotropin ranges appear to be age-dependent, raising concern for potentially inappropriate levothyroxine use. Hyperthyroidism and Graves' disease continue to be predominant in reproductive-age women but exhibit a milder phenotype at diagnosis. Thyroid nodules are increasingly found in asymptomatic patients, likely from more widespread use of neck and chest imaging. Thyroid cancer incidence has risen exponentially over the years, mostly driven by overdiagnosis of low-risk tumors; however, a small rise in incidence of higher risk tumors has been noted. Obesity appears to be a risk factor for thyroid cancer occurrence and more aggressive forms of the disease.

SUMMARY

Understanding epidemiologic trends in thyroid disease is crucial for guiding clinical practice and research efforts, aiming to optimize patient outcomes while preventing unnecessary and potentially harmful interventions.

Early-pregnancy sex steroid and thyroid function hormones, thyroid autoimmunity, and maternal papillary thyroid cancer incidence in the Finnish Maternity Cohort

Thyroid cancer more commonly affects women than men and is the third most frequently diagnosed cancer among women of reproductive age. We conducted a nested case-control study within the Finnish Maternity Cohort to evaluate pre-diagnostic sex steroid and thyroid function markers in relation to subsequent maternal papillary thyroid cancer. Cases (n = 605) were women ages 18-44 years, who provided an early-pregnancy (<20 weeks gestation) blood sample and were diagnosed with papillary thyroid cancer up to 11 years afterward. Controls (n = 1185) were matched to cases 2:1 by gestational age, mother's age, and date at blood draw. Odds ratios (ORs) for the associations of serum thyroid peroxidase antibodies (TPO-Ab), thyroglobulin antibodies (Tg-Ab), thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), progesterone, and estradiol with papillary thyroid cancer were estimated using conditional logistic regression. TPO-Ab and Tg-Ab positivity (>95th percentile among controls) were associated with more than 3-fold (OR = 3.32, 95% confidence interval [CI] 2.33-4.72) and 2-fold (OR = 2.03, 95% CI 1.41-2.93) increased odds of papillary thyroid cancer, respectively. These associations were similar by time since blood draw, parity, gestational age, smoking status, and age and stage at diagnosis. In models excluding TPO-Ab or Tg-Ab positivity, TPO-Ab (quartile 4 vs. 1: OR = 1.66, 95% CI 1.17-2.37, p-trend = .002) and Tg-Ab (quartile 4 vs. 1: OR = 1.74, 95% CI 1.22-2.49, p-trend = .01) levels were positively associated with papillary thyroid cancer. No associations were observed for estradiol, progesterone, TSH, fT3, or fT4 overall. Our results suggest that thyroid autoimmunity in early pregnancy may increase the risk of maternal papillary thyroid cancer.

The Pattern of Thyroid Cancers in Nigeria: a Systematic Review and Meta-analysis

Thyroid cancer is the most common endocrine cancer. There are various histopathological types requiring different therapeutic approaches and having variable prognoses. The objective of this study was to determine the pattern of thyroid cancers in Nigeria. The systematically searched databases were African Journal Online, Google Scholar, PubMed, and SCOPUS. The pre-print databases Research Square, SciELO, and medRxiv were also systematically searched. Moreover, the available grey literature was equally searched. The quality of the selected studies was assessed using the Newcastle-Ottawa scale. The meta-analysis was done using Meta XL version 5.3. The DerSimonian Laird random effect model was used for the meta-analysis. The heterogeneity of the selected studies was determined using the I2 statistic and Cochran's Q test. Publication bias was assessed with the Luis Furuya-Kanamori (LFK) index and Doi plot. Twenty-six studies met the eligibility criteria. The total sample size was 1224. In Nigeria, thyroid cancer was most common in the 4th and 5th decades of life. It was 3.5 (95% CI 3.0-4.6, p < 0.0001) times commoner in females than males. The pooled proportions of thyroid cancers included papillary thyroid cancer, 46% (95% CI 40-53); follicular thyroid cancer, 39% (95% CI 32-45); medullary thyroid cancer, 7% (95% CI 6-9); and anaplastic thyroid cancer, 5% (95% CI 3-7). The trend showed a change from follicular cancer predominance to papillary cancer over the past two decades. Papillary thyroid cancer is the commonest type in Nigeria. Thyroid cancer is seen more in females and it occurs most commonly in middle age.

Investigation of the causal relationship between breast cancer and thyroid cancer: a set of two-sample bidirectional Mendelian randomization study

PURPOSE

A potential association between breast (BC) and thyroid cancer (TC) has been observed. We investigated if the relationship between BC and TC is causal using bidirectional Mendelian randomization (MR) in Asian and European populations.

METHODS

BC-linked single nucleotide polymorphisms (SNPs) were acquired from a genome-wide association study (GWAS) conducted by the Breast Cancer Association Consortium and Biobank Japan. The most recent TC GWAS data were obtained from the FinnGen Project and National Biobank of Korea. We assessed the potential causal relationship between BC and TC using various MR methods, including inverse-variance-weighting (IVW). Sensitivity, heterogeneity, and pleiotropic tests were performed to assess reliability.

RESULTS

We found a bidirectional causal association between BC and TC within Europeans (IVW, TC on BC: odds ratio [OR] 1.090, 95% confidence interval [CI]: 1.012-1.173, P = 0.023; BC on TC: OR 1.265, 95% CI: 1.158-1.381, P < 0.001). A one-way causal relationship between BC susceptibility and TC risk was found in Asians (IVW BC on TC: OR 2.274, 95% CI: 2.089-2.475, P < 0.001). Subsequently, we identified a noteworthy bidirectional causal relationship between estrogen receptor (ER)-positive BC and TC (IVW, TC on ER-positive BC: OR 1.104, 95% CI: 1.001-1.212, P = 0.038; ER-positive BC on TC: OR 1.223, 95%CI: 1.072-1.395, P = 0.003), but not ER-negative BC and TC in Europeans.

CONCLUSION

We revealed a reciprocal causal association between ER-positive BC and TC. These findings establish a theoretical framework for the simultaneous surveillance and treatment of BC and TC.

Thyroid cancer risk in women after hysterectomy: A nationwide cohort study

OBJECTIVES

Hysterectomy is commonly performed for benign uterine pathologies but there is some controversy over whether it is associated with an increased risk of thyroid cancer. This study examines the associations of hysterectomy with ovarian conservation or with bilateral salpingo-oophorectomy and thyroid cancer incidence in Taiwan.

METHODS

We analyzed data from a nationwide health insurance claims database and identified 29,577 women aged ≥30 years who underwent hysterectomy with ovarian conservation or hysterectomy with bilateral salpingo-oophorectomy between 2000 and 2016. Propensity score-matching analyses were performed at ratios of 1:1 for the hysterectomy and no-hysterectomy groups, to reduce selection bias. We monitored thyroid cancer occurrence in both groups until 2017. Cox regression was used to calculate hazard ratios with 95 % confidence intervals and determine thyroid cancer risk in women who underwent hysterectomy.

RESULTS

The study comprised 29,577 patients who underwent any hysterectomy and 29,577 participants who did not. The mean follow-up period was 10.03 ± 4.92 years. Patients who underwent hysterectomy had higher thyroid cancer incidence (4.72 per 10,000 person-years) than those who did not (3.06 per 10,000 person-years) and a greater risk of any thyroid cancer (adjusted hazard ratio = 1.40; 95 % confidence interval = 1.08-1.82). However, there was no association between hysterectomy with bilateral salpingo-oophorectomy and thyroid cancer incidence (p > 0.05).

CONCLUSIONS

Our findings suggest that women who undergo hysterectomy are at a higher risk of developing thyroid cancer than those who do not.

Thyroid cancer and pregnancy: a systematic ten-year-review

Background

Thyroid cancer is the second most common malignancy during pregnancy, especially the well-differentiated thyroid cancer (well-DTC). Therefore, complex medical and social dilemmas arise, dealing with which requires deep knowledge of the nature and characteristics of the disease and pregnancy as a whole. The purpose of this review is to present the diagnostic and therapeutic strategies of thyroid cancer during pregnancy and the postpartum period.

Methods

Extended review of the literature [2011-2023] was performed. Two hundred ninety-six articles were found, from which 225 were excluded due to irrelevant subjects. Seventy-one articles were assessed for eligibility, from which 33 articles were cohort studies and case reports and were included in the review.

Results

From the 33 included studies, 18 were retrospective cohort studies, 1 was cohort study, 2 were case control studies, 1 was meta-analysis and 11 were case reports. The primary endpoints of these studies refer to the progression and recurrence of DTC during pregnancy, the prevalence of thyroid cancer in pregnancy and the most appropriate time for surgical intervention.

Conclusions

The majority of the studies agree that well-differentiated tumors with mild clinical and imaging characteristics do not require immediate surgical treatment, but mere monitoring. Surgery can be delayed after childbirth. In contrast, tumors with aggressive behavior as well as non-differentiated ones, require immediate surgery because delay under these circumstances can dramatically reduce survival rates. Finally, a history of thyroid cancer does not seem to affect future deliveries, on condition that no residual disease exists at the onset of pregnancy.

Circulating endogenous sex steroids and risk of differentiated thyroid carcinoma in men and women

Thyroid cancer (TC) is substantially more common in women than in men, pointing to a possible role of sex steroid hormones. We investigated the association between circulating sex steroid hormones, sex hormone binding globulin (SHBG) and the risk of differentiated TC in men and women within the European Prospective Investigation into Cancer and nutrition (EPIC) cohort. During follow-up, we identified 333 first primary incident cases of differentiated TC (152 in pre/peri-menopausal women, 111 in post-menopausal women, and 70 in men) and 706 cancer-free controls. Women taking exogenous hormones at blood donation were excluded. Plasma concentrations of testosterone, androstenedione, dehydroepiandrosterone, estradiol, estrone and progesterone (in pre-menopausal women only) were performed using liquid chromatography/mass spectrometry method. SHBG concentrations were measured by immunoassay. Odds ratios (ORs) were estimated using conditional logistic regression models adjusted for possible confounders. No significant associations were observed in men and postmenopausal women, while a borderline significant increase in differentiated TC risk was observed with increasing testosterone (adjusted OR T3 vs T1: 1.68, 95% CI: 0.96-2.92, ptrend = .06) and androstenedione concentrations in pre/perimenopausal women (adjusted OR T3 vs T1: 1.78, 95% CI: 0.96-3.30, ptrend = .06, respectively). A borderline decrease in risk was observed for the highest progesterone/estradiol ratio (adjusted OR T3 vs T1: 0.54, 95% CI: 0.28-1.05, ptrend = .07). Overall, our results do not support a major role of circulating sex steroids in the etiology of differentiated TC in post-menopausal women and men but may suggest an involvement of altered sex steroid production in pre-menopausal women.

Trends and projections of the global burden of thyroid cancer from 1990 to 2030

Background

We aimed to explore the burden of thyroid cancer worldwide from 1990 to 2019 and to project its future trends from 2020 to 2030.

Methods

Based on annual data on thyroid cancer cases from 1990 to 2019 available in the Global Burden of Disease (GBD) database, we calculated the age-standardised incidence, death, and disability-adjusted life year (DALY) rates for thyroid cancer. We used the estimated annual percentage change (EPAC) to quantify the temporal trends in these age-standardised rates from 1990 to 2019 and applied generalised additive models to project the disease burden from 2020 to 2030.

Results

The global age-standardised incidence rate (ASIR) of thyroid cancer increased from 1990 to 2019, with a higher overall disease burden in women than in men at both study time points. The male-to-female ratios for the ASIR increased from 0.41 in 1990 to 0.51 in 2019, while the ratio for the age-standardised death rate (ASDR) increased from 0.60 to 0.82. The models predicted the United Arab Emirates would have the fastest rising trend in both the ASIR (estimated annual percentage changes (EAPC) = 4.19) and age-standardised DALY rate (EAPC = 4.36) in 2020-30, while Saint Kitts and Nevis will have the fastest rising trend in the ASDR (EAPC = 2.29). Meanwhile, the growth trends for the ASDR and age-standardised DALY rate are projected to increase across countries in this period. A correlation analysis of the global burden of thyroid cancer between 1990-2019 and 2020-30 showed a significant positive correlation between the increase in the ASIR and socio-demographic index (SDI) in low-SDI and low-middle-SDI countries.

Conclusions

The global burden of thyroid cancer is increasing, especially in the female population and in low-middle-SDI regions, underscoring a need to target them for effective prevention, diagnosis, and treatment.

Impact of benzo[a]pyrene, PCB153 and sex hormones on human ESC-Derived thyroid follicles using single cell transcriptomics

INTRODUCTION

Endocrine disruptors are compounds of manmade origin able to interfere with the endocrine system and constitute an important environmental concern. Indeed, detrimental effects on thyroid physiology and functioning have been described. Differences exist in the susceptibility of human sexes to the incidence of thyroid disorders, like autoimmune diseases or cancer.

METHODS

To study how different hormonal environments impact the thyroid response to endocrine disruptors, we exposed human embryonic stem cell-derived thyroid organoids to physiological concentrations of sex hormones resembling the serum levels of human females post-ovulation or males of reproductive age for three days. Afterwards, we added 10 µM benzo[a]pyrene or PCB153 for 24 h and analyzed the transcriptome changes via single-cell RNA sequencing with differential gene expression and gene ontology analysis.

RESULTS

The sex hormones receptors genes AR, ESR1, ESR2 and PGR were expressed at low levels. Among the thyroid markers, only TG resulted downregulated by benzo[a]pyrene or benzo[a]pyrene with the "male" hormones mix. Both hormone mixtures and benzo[a]pyrene alone upregulated ribosomal genes and genes involved in oxidative phosphorylation, while their combination decreased the expression compared to benzo[a]pyrene alone. The "male" mix and benzo[a]pyrene, alone or in combination, upregulated genes involved in lipid transport and metabolism (APOA1, APOC3, APOA4, FABP1, FABP2, FABP6). The combination of "male" hormones and benzo[a]pyrene induced also genes involved in inflammation and NFkB targets. Benzo[a]pyrene upregulated CYP1A1, CYP1B1 and NQO1 irrespective of the hormonal context. The induction was stronger in the "female" mix. Benzo[a]pyrene alone upregulated genes involved in cell cycle regulation, response to reactive oxygen species and apoptosis. PCB153 had a modest effect in presence of "male" hormones, while we did not observe any changes with the "female" mix.

CONCLUSION

This work shows how single cell transcriptomics can be applied to selectively study the in vitro effects of endocrine disrupters and their interaction with different hormonal contexts.

Cancer incidence in Iran in 2016: A study based on the Iranian National Cancer Registry

BACKGROUND

Cancer poses an escalating public health challenge, necessitating a comprehensive understanding of cancer incidence to formulate effective control strategies.

AIMS

This study aims to present a comprehensive overview of cancer incidence in Iran, utilizing data from the Iranian National Population-based Cancer Registry (INPCR) for the year 2016.

METHODS

The study employed INPCR data to compute crude and age-standardized incidence rates (ASR) per 100 000 for the most common cancers among men and women across Iran's 31 provinces. Data analysis utilized Excel (2019) and STATA 14.

RESULTS

In 2016, 124 833 new cancer cases were registered, with 65 495 (52.90%) occurring in men and 58 312 (47.10%) in women. ASRs for all cancers in the total population were 177.48, with specific rates for men and women at 192.96 and 162.33, respectively. The five most common cancers in men were prostate (23.25), stomach (21.56), colon (19.30), bladder (16.20), and lung (13.15). Among women, the leading cancers were breast (40.60), colon (14.64), thyroid (10.84), stomach (10.25), and lung (5.63). West Azarbaijan had the highest incidence among men, while Yazd topped the list for women. Age-specific incidence rates revealed peaks in the 67-74 age group for men and the 40-50 age group for women.

CONCLUSION

This study affirms that while Iran exhibits a lower cancer incidence compared to global averages, there has been a temporal increase. Disparities in ASR exist across sexes and provinces, with shifts in the ranking of common cancers by sex compared to previous reports.

Unbalanced bidirectional causal association between thyroid cancer and ER-positive breast cancer: should we recommend screening for thyroid cancer in breast cancer patients?

BACKGROUND

The association between breast cancer (BC) and thyroid cancer (TC) has been studied in several epidemiological studies. However, the underlying causal relationship between them is not yet clear.

METHODS

The data from the latest large-sample genome-wide association studies (GWAS) of BC and TC were searched in the public GWAS database. The BC GWAS data included estrogen receptor (ER)-positive and negative subgroups. Two-way two-sample Mendelian Randomization (MR) was used to explore the potential causal relationship between BC and TC. Inverse variance weighting (IVW) and the MR-Egger method were used to combine the estimation of each single nucleotide variation (previous single nucleotide polymorphism). BC was taken as the result, and the effect of TC exposure was analyzed. Then, the effect of BC exposure on the result of TC was analyzed.

RESULTS

Both IVW and MR-Egger results indicated that gene-driven thyroid cancer does not cause estrogen receptor-positive breast cancer and is a protective factor (β = -1.203, SE = 4.663*10-4, P = 0.010). However, gene-driven estrogen receptor-positive breast cancer can lead to the development of thyroid cancer (β = 0.516, SE = 0.220, P = 0.019).

CONCLUSION

From the perspective of gene drive, people with TC are less likely to have ER-positive BC. In contrast, people with ER-positive BC are more likely to have TC. Therefore, it is recommended that patients with BC be screened regularly for TC.

Global incidence and prevalence of differentiated thyroid cancer in childhood: systematic review and meta-analysis

Objective

Differentiated thyroid cancer (DTC) is rare in childhood and adolescence although it represents the most frequent endocrine malignancy in this population. DTC includes both papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC). Most pediatric DTCs are PTCs, while FTCs are rare. To date, no systematic reviews on the global epidemiology of pediatric and adolescent DTC have been published. This systematic review and meta-analysis aims to estimate the overall incidence and prevalence of DTCs in patients aged 0-19 years.

Methods

The systematic research was conducted from January 2000 to December 2021 through MEDLINE via PubMed, Cochrane Library, and Embase databases. Two separate meta-analyses were performed for PTC and FTC.

Results

After the selection phase, a total of 15 studies (3,332 screened) met the inclusion criteria and are reported in the present systematic review. Five studies were conducted in Europe, five in North America, two in South America, one in Asia, one reported data for 49 countries and territories across the five continents, and one from both the USA and Africa. Most of the studies (n = 14) reported data obtained from national registries, and only one provided information collected from hospital medical records. Beyond the actual trend over time, our study reported a pooled global incidence rate (IR) of PTC and FTC in the pediatric age of 0.46 (95% CI: 0.33-0.59) and 0.07 (95% CI: 0.02-0.12) per 100,000 person-years, respectively. The highest IRs were recorded among Caucasian girls, and the lowest in black or other races/ethnicities.

Conclusion

Our data confirm that DTC in the pediatric population is a rare condition. The pooled IRs of the studies included in this meta-analysis are ~0.5 for PTC, which is the most common histological type when both genders and all age groups are considered. The implementation of a prospective international registry on pediatric DTC, as part of the wider European Registries for Rare Endocrine Conditions, has been recently proposed. In addition to providing relevant information on the clinical behavior of this rare disease, standardization of data collection will be pivotal to fill current gaps and allow an accurate estimation of the real incidence and risk factors of DTC.

Women consuming oral contraceptives containing cyproterone acetate and ethinylestradiol show a higher risk of thyroid cancer than nonusers

This study explored whether the risk of thyroid cancer in Asian women is associated with consumption of oral contraceptives (Diane-35). We conducted a population-based, retrospective cohort study using the Taiwan National Health Insurance Research Database. From the database, 9865 women aged 18 to 65 years who were prescribed Diane-35 between 2000 and 2012 were included in the Diane-35 group, and 39,460 women who were not prescribed Diane-35 were included in the comparison group and were frequency-matched by age and index year. Both groups were followed until 2013 to calculate the incidence of thyroid cancer. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazard model. The median (standard deviation) follow-up duration was 7.08 (3.63) and 7.04 (3.64) years in the Diane-35 and the comparison group, respectively. The incidence of thyroid cancer was 1.80-fold higher in the Diane-35 group than in the comparison group (2.72 vs 1.51 per 10,000 person-years). The cumulative incidence of thyroid cancer was significantly higher in the Diane-35 group than in the comparison group (log-rank test, P = .03). An elevated hazard ratio of thyroid cancer was observed in the Diane-35 group than in the comparison group (HR: 1.91, 95% CI: 1.10-3.30). In subgroup analysis, patients aged 30 to 39 years showed a higher hazard ratio of developing thyroid cancer after consuming Diane-35 than those in the comparison group (HR: 5.58, 95% CI: 1.84-16.91). The study provides evidence that women aged 30 to 39 years consuming Diane-35 are at increased risk of thyroid cancer. Nevertheless, a larger population with a longer follow-up may be necessary to confirm causality.

An integrative analysis of the tumor suppressors and oncogenes from sexual dimorphism and gene expression alteration features in thyroid cancer

BACKGROUND

The incidence of thyroid cancer has risen rapidly over the last decades. Although mortality rates are relatively low compared to other cancers, the rate of new cases started to increase in the early 2000s. While tumor suppressors and oncogenes were recently identified in thyroid cancer, the potential roles of these genes in thyroid cancer remain unclear.

OBJECTIVE

Analyze the roles and functions of tumor suppressors and oncogenes in thyroid cancer.

METHODS

Thyroid cancer data were collected from public databases, such as the UCSC Xena database of TCGA thyroid cancer, TISIDB, and UALCAN. The genes frequently associated with unfavorable thyroid cancer were examined and validated. The association of these target genes with thyroid tumorigenesis, stages, subtypes, and survival rates were analyzed. Additionally, the genes aberrantly expressed in thyroid cancer and significantly involved in thyroid tumorigenesis, stages, subtypes, and survival rates were identified.

RESULTS

Female sex was identified as a risk factor for thyroid cancer. The expression of PAPSS2, PDLIM3, COPZ2, ALDH1B1, ANTXR1, GUF1, and SENP6 negatively correlated with thyroid cancer prognosis.

CONCLUSION

Female sex was a risk factor for thyroid cancer. In addition, our analysis suggested that PAPSS2, PDLIM3, COPZ2, ALDH1B1, ANTXR1, GUF1, and SENP6 are negatively correlated with the prognosis of thyroid cancer. The expression of ANTXR1, GUF1, and PDLIM3 was weakly associated with thyroid cancer's immune and molecular subtypes.

Exposure to Bisphenol A increases malignancy risk of thyroid nodules in overweight/obese patients

Bisphenol A (BPA) is a widespread thyroid disruptor, but evidence about an association with thyroid cancer is weak. Excess body weight is a risk factor for thyroid cancer and affects activity of endocrine disruptors. Aim of the study was to investigate the association between BPA exposure and thyroid cancer, verifying the effect modification related to body weight. We performed a multicentre, cross-sectional study including consecutive patients referring for nodular goiter. The quantitative determination of BPA in serum samples was performed through high performance liquid chromatography system, coupled in tandem with ultraviolet and fluorescence detection. Ninety-six patients were included: 55 benign nodules, 41 thyroid cancers, 28 normal weight, and 68 overweight/obese. BPA was detected in 79 subjects. In the overall study population and in the group with BMI<25 kg/m² BPA exposure was not significantly correlated to thyroid cancer (p = 0.08 and 0.759, respectively). In the group with BMI≥25 kg/m², BPA-exposed subjects showed significantly higher risk of malignancy (OR: 5.3, p = 0.028). At multivariate analysis, such association was independent of smoking, alcohol consumption, occupational exposure, and phthalates exposure (p = 0.021 and 0.016, respectively), but was lost after adjustment for the presence of metabolic syndrome (p = 0.089). In overweight/obese subjects, BPA exposure was significantly associated with higher thyroid stimulating hormone levels. Our study suggests that BPA exposure is a risk factor for thyroid cancer in overweight/obese subjects.

The co-occurrence of both breast- and differentiated thyroid cancer: incidence, association and clinical implications for daily practice

Background

Breast cancer (BC) and differentiated thyroid cancer (TC) are two common cancer types with the highest incidence in women. BC and TC can develop synchronous or metachronous and the occurrence of both is higher than expected by chance. This study aimed to examine the association between BC and TC in the Netherlands.

Methods

This is a retrospective cohort study during the period of 1989–2020 retrieved from the Netherlands Cancer Registry (NCR). Patients diagnosed with BC-TC and BC alone as control group and TC-BC and TC alone as control group were included. The primary outcome was the standardized incidence ratio (SIR) of BC-TC and TC-BC. Secondary outcomes included data on the demographics, type of malignancy, treatment and overall survival (OS).

Results

The incidence of TC among 318.002 women with BC (BC-TC) was 0.1% (423 patients) (SIR = 1.86 (95% CI: 1.40–2.32)) and the incidence of BC among 12,370 patients with TC (TC-BC) was 2.9% (355 patients) (SIR = 1.46 (95% CI: 1.09–1.83)). BC-TC patients were younger compared to the BC alone group at BC diagnosis (55 vs 60 years, p < 0.001). The age-adjusted odds ratio to develop TC was not significantly increased for patients who received chemotherapy and radiotherapy. Most TC cases were synchronous tumors after BC diagnosis (19%) with a TNM stage 1. Only 6% of the BC tumors after TC occurred synchronous with a TNM stage 1 in most cases. The OS of all groups was the most favorable in patients with both BC and TC compared to BC- and TC alone.

Conclusion and relevance

The SIR of TC after BC diagnosis and BC after TC diagnosis was higher than predicted based on the rates of the general population. TC and BC as second primary tumors were diagnosed in an early stage and did not affect overall survival. Therefore, Dutch women who have been treated for BC or TC require no special surveillance for their thyroid- and breast gland.

DNMT3B-mediated FAM111B methylation promotes papillary thyroid tumor glycolysis, growth and metastasis

Over the past decades, the incidence of thyroid cancer (TC) rapidly increased all over the world, with the papillary thyroid cancer (PTC) accounting for the vast majority of TC cases. It is crucial to investigate novel diagnostic and therapeutic targets for PTC and explore more detailed molecular mechanisms in the carcinogenesis and progression of PTC. Based on the TCGA and GEO databases, FAM111B is downregulated in PTC tissues and predicts better prognosis in PTC patients. FAM111B suppresses the growth, migration, invasion and glycolysis of PTC both in vitro and in vivo. Furthermore, estrogen inhibits FAM111B expression by DNMT3B methylation via enhancing the recruitment of DNMT3B to FAM111B promoter. DNMT3B-mediated FAM111B methylation accelerates the growth, migration, invasion and glycolysis of PTC cells. In clinical TC patient specimens, the expression of FAM111B is inversely correlated with the expressions of DNMT3B and the glycolytic gene PGK1. Besides, the expression of FAM111B is inversely correlated while DNMT3B is positively correlated with glucose uptake in PTC patients. Our work established E2/DNMT3B/FAM111B as a crucial axis in regulating the growth and progression of PTC. Suppression of DNMT3B or promotion of FAM111B will be potential promising strategies in the estrogen induced PTC.

Hormonal Crosstalk Between Thyroid and Breast Cancer

Differentiated thyroid cancer and breast cancer account for a significant portion of endocrine-related malignancies and predominately affect women. As hormonally responsive tissues, the breast and thyroid share endocrine signaling. Breast cells are responsive to thyroid hormone signaling and are affected by altered thyroid hormone levels. Thyroid cells are responsive to sex hormones, particularly estrogen, and undergo protumorigenic processes upon estrogen stimulation. Thyroid and sex hormones also display significant transcriptional crosstalk that influences oncogenesis and treatment sensitivity. Obesity-related adipocyte alterations-adipocyte estrogen production, inflammation, feeding hormone dysregulation, and metabolic syndromes-promote hormonal alterations in breast and thyroid tissues. Environmental toxicants disrupt endocrine systems, including breast and thyroid homeostasis, and influence pathologic processes in both organs through hormone mimetic action. In this brief review, we discuss the hormonal connections between the breast and thyroid and perspectives on hormonal therapies for breast and thyroid cancer. Future research efforts should acknowledge and further explore the hormonal crosstalk of these tissues in an effort to further understand the prevalence of thyroid and breast cancer in women and to identify potential therapeutic options.

Hypertension and Obesity: Risk Factors for Thyroid Disease

Thyroid disease instances have rapidly increased in the past few decades; however, the cause of the disease remains unclear. Understanding the pathogenesis of thyroid disease will potentially reduce morbidity and mortality rates. Currently, the identified risk factors from existing studies are controversial as they were determined through qualitative analysis and were not further confirmed by quantitative implementations. Association rule mining, as a subset of data mining techniques, is dedicated to revealing underlying correlations among multiple attributes from a complex heterogeneous dataset, making it suitable for thyroid disease pathogenesis identification. This study adopts two association rule mining algorithms (i.e., Apriori and FP-Growth Tree) to identify risk factors correlated with thyroid disease. Extensive experiments were conducted to reach impartial findings with respect to knowledge discovery through two independent digital health datasets. The findings confirmed that gender, hypertension, and obesity are positively related to thyroid disease development. The history of I₁₃₁ treatment and Triiodothyronine level can be potential factors for evaluating subsequent thyroid disease.

Development and validation of a novel diagnostic tool for predicting the malignancy probability of thyroid nodules: A retrospective study based on clinical, B-mode, color doppler and elastographic ultrasonographic characteristics

BACKGROUND

Clinicians estimate the risk of thyroid nodules and make subsequently decision on the basis of clinical and ultrasonographic findings. Currently, there is no comprehensive diagnostic tool for predicting the malignancy rates of thyroid nodules. Our aim was to develop and validate a novel integrate diagnostic tool for predicting the malignancy probability of thyroid nodules based on clinical, B-mode, Color Doppler and elastographic ultrasonographic characteristics.

METHODS

A total of 1016 nodules in 1016 patients who underwent thyroid ultrasonography and surgery from July 2021 to December 2021 were included in this retrospective study. All nodules were confirmed by pathology and randomly classified into the training and validation groups. Clinical, B-mode, Color Doppler and elastographic (CBCE) ultrasonographic characteristics of nodules were recorded. Univariate and multivariate analyses were performed to screen independent predictors associated with thyroid cancer. A multivariate model containing the extracted predictors was constructed and presented in the form of a nomogram. The validation and applicability of the CBCE nomogram was evaluated using the receiver operating characteristic (ROC) curve. Diagnostic performances were calculated to compare the CBCE nomogram with ACR-TIRADS (Thyroid Imaging Reporting Data System by American College of Radiology) and EU-TIRADS (Thyroid Imaging Reporting Data System by European Thyroid Association).

RESULTS

The following factors were included in the CBCE nomogram: patient gender, age, shape, margin, composition and echogenicity, calcification, vascularization distribution, vascularization degree, suspicious lymph node metastases and elastography. The area under the curve (AUC) values were 0.978 and 0.983 for the training and validation groups, respectively. Compared with ACR-TIRADS and EU-TIRADS, the CBCE nomogram showed improved accuracy (0.944) and specificity (0.913) without sacrificing sensitivity (0.963) and showed the highest AUC with an optimal cutoff value of 0.55.

CONCLUSION

The CBCE nomogram has good and high clinical practicability in predicting the malignancy probability of thyroid nodules.

Temporal and geographical variations of thyroid cancer incidence and mortality in France during 1986-2015: The impact of overdiagnosis

BACKGROUND

France is among the countries showing fastest growth of thyroid cancer (TC) incidence and highest incidence rates in Europe. This study aimed to clarify the temporal and geographical variations of TC in France and to quantify the impact of overdiagnosis.

METHODS

We obtained TC incidence data in 1986-2015, and mortality data in 1976-2015, for eight French departments covering 8% of the national population, and calculated the age-standardised rates (ASR). We estimated the average annual percent changes (AAPC) of TC incidence, overall and by department and histological subtype. Numbers and proportions of TC cases attributable to overdiagnosis were estimated by department and period, based on the comparison between the shape of the age-specific curves with that observed prior to changes in diagnostic practice.

RESULTS

During 1986-2015, there were 13,557 TC cases aged 15-84 years. Large variations of TC incidence were observed across departments, with the highest ASR and the fastest increase in Isère. Papillary subtype accounted for 82.8% of the cases, and presented an AAPC of 7.0% and 7.6% in women and men, respectively. Anaplastic TC incidence decreased annually 3.0% in women and 0.8% in men. Mortality rates declined consistently for all departments. The absolute number (and proportion) of TC cases attributable to overdiagnosis grew from 1074 (66%) in 1986-1995 to 3830 (72%) in 2006-2015 in women, and varied substantially across departments.

CONCLUSIONS

Overdiagnosis plays an important role in the temporal and regional variations of TC incidence in France. Monitoring the time trends and regulating the regional healthcare practice are needed to reduce its impact.

Evaluation of Gender Inequity in Thyroid Cancer Diagnosis: Differences by Sex in US Thyroid Cancer Incidence Compared With a Meta-analysis of Subclinical Thyroid Cancer Rates at Autopsy

IMPORTANCE

Thyroid cancer is more common in women than in men, but the associated causes of these differences are not fully understood.

OBJECTIVE

To compare sex-specific thyroid cancer rates in the US to the prevalence of subclinical thyroid cancer at autopsy.

DATA SOURCES

Data on thyroid cancer incidence and mortality by sex among US adults (≥18 years) were extracted from the National Cancer Institute's Surveillance, Epidemiology, and End Results Program (SEER) data for 1975 to 2017. Embase, PubMed, and Web of Science databases were searched for studies on the prevalence of subclinical thyroid cancer at autopsy of men and women, from inception to May 31, 2021.

STUDY SELECTION

The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline was used to perform a systematic search for articles reporting the prevalence of subclinical thyroid cancer in autopsy results of both women and men. Of 101 studies identified, 8 studies containing 12 data sets met inclusion criteria; ie, they examined the whole thyroid gland, stated the number of thyroids examined, and reported results by sex. Excluded studies reported thyroid cancer in Japan after the atomic bombs or Chernobyl after the nuclear disaster; did not examine the whole thyroid gland or had incomplete information on thyroid examination methods; or did not report rates by sex.

DATA EXTRACTION AND SYNTHESIS

Thyroid cancer incidence and mortality data by sex, histologic type, and tumor size were extracted from SEER. The inverse variance heterogeneity model was used to meta-analyze the prevalence and the odds ratio of subclinical thyroid cancer by sex from 8 studies (12 data sets) on thyroid cancer prevalence in autopsy results.

MAIN OUTCOMES AND MEASURES

Incidence and mortality of thyroid cancer, by histologic type and tumor size; prevalence of thyroid cancer in autopsy results.

RESULTS

In 2017, 90% of thyroid cancers diagnosed were papillary thyroid cancer (PTC) and in 2013 to 2017, the women to men incidence ratio for small (≤2 cm) PTC was 4.39:1. The incidence ratio approached 1:1 as cancer type lethality increased. The ratio of thyroid cancer mortality by gender was 1.02:1 and remained stable from 1992 to 2017. Results of the meta-analysis showed that the pooled autopsy prevalence of subclinical PTC was 14% in women (95% CI, 8%-20%) and 11% in men (95% CI, 5%-18%). The pooled odds ratio of subclinical PTC in women compared with men was 1.07 (95% CI, 0.80-1.42).

CONCLUSIONS AND RELEVANCE

This cohort study and meta-analysis found that the belief that women get thyroid cancer more often than men is an oversimplification. The gender disparity is mostly confined to the detection of small subclinical PTCs, which are equally common in both sexes at autopsy but identified during life much more often in women than men. As the lethality of the cancer type increases, the ratio of detection by gender approaches 1:1. This phenomenon may be associated with gender differences in health care utilization and patterns of clinical thinking and can harm both women, who are subject to overdetection, and men, who may be at risk of underdetection.

Pregnancy Does not Affect the Prognoses of Differentiated Thyroid Cancer Patients With Lung Metastases

CONTEXT

Pregnancy-related hormones may stimulate thyroid cancer growth, but whether pregnancy affects the prognoses of patients with lung metastases from differentiated thyroid cancer (DTC-LM) after surgery and radioiodine therapy is unclear.

OBJECTIVE

To assess the impact of pregnancy on DTC-LM through the comparison of prognoses between female patients with DTC-LM who did and did not become pregnant after surgery and radioiodine therapy.

METHODS

We retrospectively analyzed the records of 124 female patients aged 16 to 35 years who underwent surgery and radioiodine therapy for DTC-LM. These patients were divided into pregnancy group (n = 37) and nonpregnancy group (n = 87) according to whether they became pregnant after surgery and radioiodine therapy, regardless of whether they had a pregnant history before treatment.

RESULTS

The 5- and 10-year progression-free survival rates were 94.52% and 63.22% in pregnancy group versus 89.82% and 58.13% in nonpregnancy group. The 5- and 10-year cumulative overall survival rates of pregnancy group were 97.30% and 85.77% versus 93.50% and 81.95% in nonpregnancy group (all P > 0.05). The median time of follow-up in the pregnancy and nonpregnancy groups was 82 months (25-136 months) and 68 months (13-133 months), respectively. Non-radioiodine-avid LM and primary tumors needing repeated resection were independent predictors of poor progression-free survival for patients in pregnancy group.

CONCLUSION

Pregnancy does not affect the prognoses of patients with DTC-LM after surgery and radioiodine therapy. Non-radioiodine-avid LM and repeated primary tumor surgeries are independent risk factors for poor prognoses of pregnant patients.

Co-occurrence of thyroid and breast cancer is associated with an increased oncogenic SNP burden

BACKGROUND

Epidemiological evidence suggests that synchronous or metachronous presentation of breast and thyroid cancers exceeds that predicted by chance alone. The following potential explanations have been hypothesized: common environmental or hormonal factors, oncogenic effect of the treatment for the first cancer, closer follow-up of cancer survivors, shared underlying genetic risk factors. While some cases were found to be related to monogenic disorders with autosomal inheritance, the genetic background of most cases of co-occurring breast and thyroid cancer is thought to be polygenic.

METHODS

In this retrospective case-control study we compared the genetic profile of patients with a history of breast cancer (n = 15) to patients with co-occurring breast and thyroid cancer (n = 19) using next generation sequencing of 112 hereditary cancer risk genes. Identified variants were categorized based on their known association with breast cancer and oncogenesis in general.

RESULTS

No difference between patients with breast and double cancers was observed in clinical and pathological characteristics or the number of neutral SNPs. The unweighted and weighted number of SNPs with an established or potential association with breast cancer was significantly lower in the group with breast cancer only (mean difference - 0.58, BCa 95% CI [- 1.09, - 0.06], p = 0.029, and mean difference - 0.36, BCa 95% CI [- 0.70, - 0.02], p = 0.039, respectively). The difference was also significant when we compared the number of SNPs with potential or known association with any malignancy (mean difference - 1.19, BCa 95% CI [- 2.27, - 0.11], p = 0.032 for unweighted, and mean difference - 0.73, BCa 95% CI [- 1.32, - 0.14], p = 0.017 for weighted scores).

CONCLUSION

Our findings are compatible with the hypothesis of genetic predisposition in the co-occurrence of breast and thyroid cancer. Further exploration of the underlying genetic mechanisms may help in the identification of patients with an elevated risk for a second cancer at the diagnosis of the first cancer.

L-carnitine extenuates endocrine disruption, inflammatory burst and oxidative stress in carbendazim-challenged male rats via upregulation of testicular StAR and FABP9, and downregulation of P38-MAPK pathways

We have addressed in the current study the potential of L-carnitine (LC) to extenuate the reproductive toxic insults of carbendazim (CBZ) in male rats, and the molecular mechanisms whereby carnitine would modify the spermatogenic and steroidogenic derangements invoked by the endocrine disruptor. Herein, animals received daily doses of carbendazim (100 mg/kg) by gavage for 8 weeks. Another CBZ-challenged group was co-supplemented with LC (500 mg/kg, IP) twice weekly for 8 weeks. Sperm quantity and quality (morphology, motility and viability), serum testosterone and gonadotropins, and thyroid hormone levels were assessed. Serum tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10) concentrations were determined by ELISA. Oxidant/antioxidant status in rat testis was investigated via measuring testicular contents of malondialdehyde (MDA) and reduced glutathione (GSH), as well as the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx). Immunohistochemical localizations of the junctional protein; occludin, and inflammatory markers; inducible nitric oxide synthase (iNOS) and nuclear factor kappa beta (NF-κB) were further analyzed. A host of transduction genes that regulate spermatogenic and steroidogenic pathways, and their encoded proteins namely, Steroidogenic Acute Regulatory Protein (StAR), Fatty acid binding protein 9 (FABP9) and P38-mitogen activated protein kinase (P38-MAPK) were assessed by real time quantitative (RT-qPCR) and Western blot. LC improved rat spermiogram, testicular histological alterations and endocrine perturbances, and modulated genes' expressions and their respective proteins. In conclusion, LC effects appear to reside for the most part on its endocrine-preserving, anti-oxidant and anti-inflammatory properties through a myriad of interlaced signal transductions that ultimately recapitulated its beneficial effects on spermatogenesis and steroidogenesis.

Reproductive Factors and Risk of Thyroid Cancer in Women: An Analysis in the Nurses' Health Study II

BACKGROUND

The incidence of thyroid cancer in women is increasing at an alarming rate, with greatest risk in the reproductive years. Establishing relationships of hormonally related reproductive factors with thyroid cancer has been difficult. We aimed to elucidate potential risk factors for thyroid cancer in a large cohort of women.

METHODS

Among 116,228 women in the Nurses' Health Study II followed from 1989 to 2013, 620 cases of thyroid cancer were identified. We examined reproductive and hormone-related factors, including age at menarche, age at menopause, parity, oral contraceptive use, and postmenopausal hormone therapy use. Pregnancy, reproductive years, and months of breastfeeding were used as surrogate markers for exposure to endogenous reproductive hormones. We used multivariable Cox models to calculate relative risks and 95% confidence intervals for the associations between these factors and risk of thyroid cancer.

RESULTS

Number of reproductive years of 41 years or more was associated with more than double the risk of thyroid cancer compared with 30 years or fewer (relative risk, 2.20; 95% confidence interval, 1.19-4.06). The other variables analyzed (parity number, months of breastfeeding, age at menarche, menopausal status, and postmenopausal hormone therapy) were not associated with the risk of thyroid cancer. Women who entered menopause at age 45 years or older had a higher risk of thyroid cancer compared with women who entered menopause at a younger age. This result did not reach statistical significance; however, there was a linear trend between later age at menopause and increased risk of thyroid cancer (p_trend = .009).

CONCLUSIONS

This study used a unique large, longitudinal dataset to assess thyroid cancer risk factors and potential confounders over an extended time frame. Our key finding suggests increased risk of thyroid cancer may be associated with a variety of indicators of longer reproductive years. The Nurses' Health Study II has provided new insights into the hormonal risks associated with thyroid cancer.

The management of menopausal symptoms in women following treatment for cancer at a specialist menopause service

OBJECTIVE

The aim of this study was to identify prescribing patterns at a specialist menopause service in a central London teaching hospital for women following treatment for a malignancy.

STUDY DESIGN

This was a prospective cohort study with data collected over a seven-month period from December 2019 to June 2020. All women reviewed at the specialist menopause services following treatment of a malignancy, BRCA carriers and Lynch syndrome were included in the study, with management options divided into three categories: hormonal, non-hormonal and no treatment.

MAIN OUTCOME MEASURES

The primary outcome of this study was to identify prescribing patterns for all women reviewed following a diagnosis of a malignancy, as well as those with genetic mutations necessitating risk-reducing prophylactic bilateral salpingo-oopherectomy (BSO).

RESULTS

Altogether 71 women were included in this study, with the majority of women post management of a non-gynaecological malignancy (51/71, 72%), of which breast cancer was the most common (37/71, 52%). While non-hormonal treatment was the most popular among those treated for breast cancer, for all other malignancies, hormonal treatment was more widespread. Fourteen women also had genetic mutations, with all of these women commencing hormonal treatment post risk reducing surgery.

CONCLUSION

With the exception of those with a history of hormone-sensitive breast cancer, the use of hormonal treatment for menopausal symptoms remained widespread. While this was a relatively small study, the need for long-term follow-up across specialist menopause services, to assess the risk of recurrence is vital.

Risk of thyroid cancer following hysterectomy

BACKGROUND

Hysterectomy has been associated with increased thyroid cancer risk but whether this reflects a biological link or increased diagnosis of indolent cancers due to greater medical contact remains unclear.

METHODS

We recruited 730 women diagnosed with thyroid cancer and 785 age-matched population controls. Multivariable logistic regression was used to assess the association overall, and by tumour BRAF mutational status as a marker of potentially higher-risk cancers. We used causal mediation analysis to investigate potential mediation of the association by healthcare service use.

RESULTS

Having had a hysterectomy was associated with an increased risk of thyroid cancer (odds ratio [OR] = 1.45, 95 % confidence interval [CI] 1.07-1.96). When stratified by indication for hysterectomy, the risk appeared stronger for those who had a hysterectomy for menstrual disorders (OR = 1.67, 95 % CI 1.17-2.37) but did not differ by tumour BRAF status. Approximately 20 % of the association between hysterectomy and thyroid cancer may be mediated by more frequent use of healthcare services.

CONCLUSIONS

The observed increased risk of thyroid cancer among those with hysterectomy may be driven, at least partly, by an altered sex steroid hormone milieu. More frequent healthcare service use by women with hysterectomy accounts for only a small proportion of the association.

Hysterectomy and Risk of Breast, Colorectal, Thyroid, and Kidney Cancer - an Australian Data Linkage Study

BACKGROUND

This study aimed to investigate the associations between hysterectomy for benign indications and risk of breast, colorectal, kidney, and thyroid cancer, and to explore whether these associations are modified by removal of ovaries at the time of surgery or by age at surgery.

METHODS

We conducted a retrospective cohort study of the female population of Western Australia (n = 839,332) linking data from electoral, hospital, births, deaths, and cancer records. We used Cox regression to estimate HRs and 95% confidence intervals (CI) for the associations between hysterectomy and diagnosis of breast, colorectal, kidney, and thyroid cancers.

RESULTS

Compared with no surgery, hysterectomy without oophorectomy (hysterectomy) and hysterectomy with bilateral salpingo-oophorectomy (hysterectomy-BSO) were associated with higher risk of kidney cancer (HR, 1.32; 95% CI, 1.11-1.56 and HR, 1.29; 95% CI, 0.96-1.73, respectively). Hysterectomy, but not hysterectomy-BSO, was related to higher risk of thyroid cancer (HR, 1.38; 95% CI, 1.19-1.60). In contrast, hysterectomy (HR, 0.94; 95% CI, 0.90-0.98) and hysterectomy-BSO (HR, 0.92; 95% CI, 0.85-1.00) were associated with lower risk of breast cancer. We found no association between hysterectomy status and colorectal cancer.

CONCLUSIONS

The associations between hysterectomy and cancer varied by cancer type with increased risks for thyroid and kidney cancer, decreased risk for breast cancer, and no association for colorectal cancer.

IMPACT

As breast, colorectal, and gynecologic cancers comprise a sizeable proportion of all cancers in women, our results suggest that hysterectomy is unlikely to increase overall cancer risk; however, further research to understand the higher risk of thyroid and kidney cancer is warranted.

LncRNA PVT1 Acts as a Tumor Promoter in Thyroid Cancer and Promotes Tumor Progression by Mediating miR-423-5p-PAK3

Introduction

Thyroid cancer (TC) is an endocrine tumor whose risk of onset has been rising, so the deep understanding of its molecular mechanism helps formulate new treatment strategies.

Methods

This paper was aimed at exploring the regulatory mechanism of long non-coding RNA (LncRNA) plasmacytoma variant translocation 1 (PVT1) in TC. The expression of PVT1, miR-423-5p and p21-activated kinase 3 (PAK3) in TC tissues and cell lines was detected by real-time PCR. PAK3 levels were detected by Western blot. Regulatory relationships between target genes and the proliferation, invasion and apoptosis of cells and genes were analyzed.

Results

PVT1 and PAK3 upregulated while miR-423-5p downregulated in the tissues and cell lines. PVT1 downregulation inhibited TC cells from malignantly proliferating and invading, and promoted their apoptosis. PVT1 specifically regulated miR-423-5p, and its overexpression could weaken the anti-tumor effect of this miR on TC cells. In addition, miR-423-5p directly targeted PAK3, and knocking down its expression could weaken the inhibitory effect of PAK3 downregulation on TC progression. Besides, PVT1 acted as a competitive endogenous RNA to sponge this miR and thus regulate PAK3 expression.

Discussion

In conclusion, PVT1 can mediate the molecular mechanism of the miR-423-5p-PAK3 axis regulatory network on regulating TC, so it is a new direction of treating the disease.

Burden of Thyroid Cancer From 1990 to 2019 and Projections of Incidence and Mortality Until 2039 in China: Findings From Global Burden of Disease Study

Projecting the burden of thyroid cancer (TC) over time provides essential information to effectively plan measures for its management and prevention. This research obtained data from the Global Burden of Disease (GBD) Study from between 1990 and 2019 to model how TC will affect China until 2039 by conducting the Bayesian age-period-cohort analysis. The number of new TC cases in China was 10,030 in 1990, 39,080 in 2019, and is projected to be 47,820 in 2039. This corresponds to 3,320, 7,240, and 4,160 deaths, respectively. Disability-adjusted life years (DALYs) cases increased from 103,490 in 1990 to 187,320 in 2019. The age-standardized rate (ASR) of incidence increased from 1.01 to 2.05 during 1990-2019 and was projected to increase to 3.37 per 100,000 person-years until 2039. The ASR of mortality (ASMR) remained stable during the study period and was projected to have a mild decline from 0.39 to 0.29/100,000 during 2020-2039. Although the ASMR in male patients has maintained increasing at a rate of 2.2% per year over the past 30 years, it is expected to decline at a rate of 1.07% per year in 2019-2039. The most significant increase in crude incidence occurred in people aged 45-65 from 1990 to 2019, however, this will shift into young people aged 10-24 from 2020 to 2039. In addition, the proportion of deaths and DALYs caused by obesity increased from 1990 to 2019 and affected men more than women. In conclusion, a substantial increase in counts of incidence of TC in China is projected over the next two decades, combined with the slightly declining mortality, indicating that rational health policies are needed in the future to cope with the increasing number of TC patients, especially among males and adolescents.

The characteristics and risk factors of central compartment lymph node metastasis in cN0 papillary thyroid carcinoma coexistent with Hashimoto's thyroiditis

Background

Currently, there are few studies on the characteristics of lymph node metastasis in the central region in patients with preoperative negative lymph node (cN0) papillary thyroid carcinoma (PTC) coexistent with Hashimoto's thyroiditis (HT). There is still a significant controversy on whether to perform prophylactic central compartment lymph node dissection for T1/T2 cN0 PTC. Therefore, we aimed to investigate the characteristics and risk factors of central compartment lymph node metastasis in cN0 PTC (T1 or T2 stage) coexists with HT.

Methods

From Jun. 2015 to Apr. 2019, the clinicopathological data of 354 patients with stage T1/T2 cN0 PTC admitted to the thyroid tumor surgery of Inner Mongolia People's Hospital were analyzed retrospectively. All patients underwent central compartment lymph node dissection. According to the results of the postoperative pathological examination, the patients were divided into two groups: PTC group (n=236) and PTC coexistent with the HT group (n=118).

Results

The proportion of PTC patients with HT was 33.33% (118/354) in T1/T2 cN0 PTC patients; most of them were women. The levels of serum thyrotropin, antithyroglobulin antibody, and thyroid peroxidase antibody in PTC coexistent with HT group are higher than those in the PTC group (P<0.05). The number of lymphadenectomies in PTC coexistent with HT group was more than that in PTC alone group (P<0.05). Univariate analysis showed that antithyroglobulin antibody positive, tumor diameter >1 cm, and multifocal cancer in T1/T2 stage cN0 PTC coexistent with HT group were all correlated with lymph node metastasis in the central region (P<0.05). Logistic regression analysis showed that tumor diameter >1 cm, and multifocal cancer were the risk factors of central compartment lymph node metastasis in patients with T1/T2 stage cN0 PTC coexistent with HT (P<0.05).

Conclusions

HT is not a relevant factor of central lymph node metastasis in T1/T2 cN0 PTC; regardless of the presence or absence of HT, tumor diameter >1 cm and multifocal cancer are risk factors for central lymph node metastasis in patients with T1/T2 cN0 PTC. Therefore, preventive lymph node dissection in the central region should be conducted actively during the operation.

Incidence and Survival in Reproductive-Aged Women with Differentiated Thyroid Cancer: United States SEER 18 2000-2016

Background: Incidence of differentiated thyroid cancer has increased in the United States and globally with disproportionate increases observed among women. Recent data suggest that factors other than increased detection may underlie this increase. To understand incidence and survival patterns in differentiated thyroid cancer during a time period of increasing imaging, we examined data from a contemporary population-based sample of U.S. reproductive-aged women. Methods: Women aged 20-49 years (N = 61,552) diagnosed with papillary thyroid cancer (PTC) or follicular thyroid cancer (FTC) during 2000-2016 were identified from the U.S. National Cancer Institute Surveillance, Epidemiology, and End Results 18 registries database. For each age decade (20-29, 30-39, 40-49 years), we estimated age-adjusted average annual percentage changes in incidence using segmented and unsegmented regression models and 15-year survival. Results were stratified by race/ethnicity and cancer stage. Results: The estimated incidence of PTC increased during 2000-2016 among women aged 20-29 years and during 2000-2012 among women aged 30-49 years. During 2012-2016, incidence stabilized among women aged 30-39 years and decreased among women aged 40-49 years. For FTC, incidence decreased slightly among women aged 20-29 years and was rather stable among those aged 30-49 years during 2000-2016, although increases were observed among non-Hispanic black women aged 30-49 years. By stage, the percentage increase in PTC incidence was largest for regional disease. Fifteen-year estimated survival was generally high but somewhat lower among women aged 40-49 years than those aged 20-39 years. Survival was similar for PTC and FTC except among women aged 20-29 years, for whom survival was modestly lower with FTC than PTC. Conclusions: Our findings confirm increasing incidence of PTC among U.S. women aged 20-29 years, a recent stabilization of PTC incidence in women 30-49 years, and stable to decreasing incidence of FTC. Increased detection based on imaging is unlikely to fully explain the continued increase in PTC incidence, given the increasing incidence of regional disease and routine imaging occurring less often among premenopausal than postmenopausal women. Although survival is generally high, treatment often requires surgery and lifelong medications. Further investigations into contributors to these trends are warranted to reduce future morbidity in reproductive-aged women.

Tamoxifen exposure in pregnancy after synchronous breast and thyroid cancer

Thyroid and breast cancer are the most common cancers among young women, which are either synchronous or metachronous, but the association is yet to be elucidated. With the improvement of diagnosis and treatment, there is an increase in breast and thyroid cancer survivors. Hence, attention is shifting towards survivorship. Here, we report the case of a young lady diagnosed with synchronous thyroid and breast cancer who unexpectedly became pregnant during tamoxifen treatment. After a multidisciplinary discussion, endocrine therapy was interrupted and she delivered a healthy baby at term. In conclusion, oncologists should be aware of breast and thyroid cancer co-occurrence and examinations should be conducted together in diagnosis and follow-up. Also, pregnancy is feasible and can be considered after synchronous breast and thyroid cancer diagnosis. Physicians need to emphasise the use of barrier contraceptives to patients undergoing endocrine therapy. However, the optimum timing for pregnancy after breast cancer and the safety of endocrine therapy interruption in hormonal-positive patients should be discussed and managed by a multidisciplinary team.

Uterine Fibroids Increase the Risk of Thyroid Cancer

Objectives: The formation of uterine fibroids (UF) is potentially linked to the development of thyroid cancer through a common factor: female sex hormones. Methods: We conducted a nationwide population-based cohort study to determine whether Taiwanese women with UF have an increased risk of thyroid cancer. The data of both the UF and control groups were derived from the National Health Insurance Research Database (NHIRD) of Taiwan. Groups were matched by the year of UF diagnosis, age, income, urbanization level, occupation, and comorbidities. A Cox proportional hazard regression model was used to compare the incidence of thyroid cancer between the UF and control groups. In addition, the model was used to determine the hazard ratio of thyroid cancer in the UF group in comparison with the control group. Results: Women with UF had a statistically significantly increased risk of thyroid cancer compared with controls (adjusted hazard ratio (aHR): 1.64, 95% confidence interval (CI): 1.26–2.13). Stratified analyses showed that women with UF who had a significantly increased risk of thyroid cancer were more likely to be middle aged, have middle and higher income levels, and a medium follow-up period (1–5 years) of UF. No other UF patient characteristics and comorbidities showed association with the risk of thyroid cancer. In addition, UF patients had a significantly increased risk of thyroid cancer regardless of whether or not they underwent myomectomy. Conclusions: The results suggest that women with UF have an increased risk of subsequent thyroid cancer. Further research is needed to explore whether surveillance strategies for the early detection of thyroid cancer using ultrasonography should be implemented among patients with UF.

Human exposure to bisphenol AF and diethylhexylphthalate increases susceptibility to develop differentiated thyroid cancer in patients with thyroid nodules

Pollutants represent potential threats to the human health, being ubiquitous in the environment and exerting toxicity even at low doses. This study aims at investigating the role of fifteen multiclass organic pollutants, assumed as markers of environmental pollution, most of which exerting endocrine-disrupting activity, in thyroid cancer development. The increasing incidence of differentiated thyroid cancer (DTC) may be related to the rising production and environmental dissemination of pollutants. Fifty-five patients, twenty-seven with diagnosis of benign thyroid nodules and twenty-eight suffering from differentiated thyroid cancer, were enrolled and the concentration levels of seven bisphenols, two phthalates (i.e. di(2-ethylhexyl) phthalate (DEHP) and its main metabolite, mono-(2-ethyl-hexyl) phthalate) (MEHP)), two chlorobenzenes, (1,4-dichlorobenzene and 1,2,4,5-tetrachlorobenzene), and 3 phenol derivatives (2-chlorophenol, 4- nonylphenol, and triclosan) were determined in their serum by using a validated analytical method based on high performance liquid chromatography with ultraviolet tandem fluorescence detection. A significant relationship was found between malignancy and the detection in the serum of both bisphenol AF and DEHP. Indeed, their presence confers a more than fourteen times higher risk of developing differentiated thyroid cancer. Relationship between these two pollutants and the risk of malignancy was dose-independent and not mediated by higher thyroid stimulating hormone levels. Even if a conclusive evidence cannot still be drawn and larger prospective studies are needed, the exposure to low doses of environmental endocrine-disrupting contaminants can be considered consistent with the development of thyroid cancer.

The Emerging Role of Estrogens in Thyroid Redox Homeostasis and Carcinogenesis

Reactive oxygen species (ROS) are the most critical class of free radicals or reactive metabolites produced by all living organisms. ROS regulate several cellular functions through redox-dependent mechanisms, including proliferation, differentiation, hormone synthesis, and stress defense response. However, ROS overproduction or lack of appropriate detoxification is harmful to cells and can be linked to the development of several diseases, such as cancer. Oxidative damage in cellular components, especially in DNA, can promote the malignant transformation that has already been described in thyroid tissue. In thyrocyte physiology, NADPH oxidase enzymes produce large amounts of ROS that are necessary for hormone biosynthesis and might contribute to the high spontaneous mutation rate found in this tissue. Thyroid cancer is the most common endocrine malignancy, and its incidence is significantly higher in women than in men. Several lines of evidence suggest the sex hormone estrogen as a risk factor for thyroid cancer development. Estrogen in turn, besides being a potent growth factor for both normal and tumor thyroid cells, regulates different mechanisms of ROS generation. Our group demonstrated that the thyroid gland of adult female rats exhibits higher hydrogen peroxide (H₂O₂) production and lower enzymatic antioxidant defense in comparison with male glands. In this review, we discuss the possible involvement of thyroid redox homeostasis and estrogen in the development of thyroid carcinogenesis.

Hormone Replacement Therapy in Cancer Survivors - Review of the Literature

Rapid advance in oncology leads to increasing survival of oncologic patients. More and more of them live long enough to reach either the natural age of menopause or, as a side effect of their oncotherapy, experience the cessation of gonadal function, leading to premature ovarian insufficiency, with disturbing vasomotor symtoms and long-term negative cardiovascular and skeletal effects. Thus, an ever increasing number of cancer survivors search endocrinologic help in the form of hormone replacement therapy (HRT). The misinterpretation of the WHI (Women's Health Initiative) Study has lead to an irrational fear of female hormone replacement, both by the general population and medical professionals. It has seemed the logical and safe conclusion to many physicians to avoid HRT, supposing that this attitude definitely causes no harm, whereas the decision of prescribing estrogen alone or with progestins might bear oncologic and thromboembolic risks and may even lead to litigation in case of a potentially related complication. However, it was known even before the WHI results that premature menopause and hypogonadism decreases the life expectancy of women by years through its skeletal and cardiovascular effects, and this negative effect correlates with the length of the hypoestrogenaemic period. Therefore, the denial of HRT also needs to be supported by evidence and should be weighed againts the risks of HRT. Yet, the oncologic risk of HRT is extremely difficult to assess. In this work we review the latest evidence from in vitro experiments to clinical studies, regarding HRT in survivors of gynecologic and non-gynecologic cancers. Based on our literature research, we group tumours regarding the oncologic risk of properly chosen female hormone replacement therapy in cancer survivors as follows: ’HRT is advanageous’ (e.g. endometrial cancer type I, cervical adenocarcinoma, haematologic malignancies, local cutaneous malignant melanoma, colorectal cancer, hepatocellular cancer); ’HRT is neutral’ (e.g. BRCA 1/2 mutation carriers without cancer, endometrial cancer type II, uterinal carcinosarcoma and adenosarcoma, certain types of ovarian cancer, cervical, vaginal and vulvar squamous cell carcinoma, prolactinoma, kidney cancer, pancreatic cancer, thyroid cancer); ’HRT is relatively contraindicated’ for various reasons (e.g. leiomyosarcoma, certain types of ovarian tumours, brain tumours, advanced metastatic malignant melanoma, lung cancer, gastric cancer, bladder cancer); ’HRT is diasadvantageous and thus contraindicated’ (e.g. breast cancer, endometrial stroma sarcoma, meningioma, glioma, hormone receptor positive gastric and bladder cancer).

Do the Fertility Drugs Increase the Risk of Cancer? A Review Study

Aim: All over the world, many couples cannot conceive a child and have problems with pregnancy. Ovulation-inducing drugs are among the most important drugs used for the treatment of infertility. In recent years, there have been many debates about the relationship between fertility medication and cancer. Due to the lack of comprehensive study of this matter, and as understanding the relationship between the use of fertility drugs and cancer is of importance, the present study was conducted to investigate the relationship between infertility drugs and cancer in women. Materials and Methods: To determine the relationship between infertility treatment and cancer, a comprehensive search was carried out in databases such as; Medline, Web of Science Core Collection, and Scopus using keywords words; "infertility," "ovulation induction," "cancer," "infertility treatment," "ART," "tumor," "controlled ovarian stimulation," "fertility agents," and "neoplasms." Full-text, English language, and original articles were included in this study. Results: In total, 81 articles were entered into the study. The relationship between fertility medications and breast, ovary, endometrial, uterus, colon, thyroid, skin, cervical, and non-Hodgkin's lymphoma cancers were studied. Although the relationship between fertility medications and cancer is theoretically justifiable, most studies have shown that risk of cancer will not increase after fertility treatment. Conclusion: The results of this study did not show that fertility medications increase the risk of cancer among users. In summary, the relationship between infertility treatment and cancer incidence remains an open question.

A Linkage Between Thyroid and Breast Cancer: A Common Etiology?

Breast and thyroid cancers are two malignancies with highest incidence in women. These cancers often occur metachronously. Women with thyroid cancer are at increased risk for subsequent breast cancer; women with breast cancer have an increased incidence of later development of thyroid cancer, suggesting a common etiology. This bidirectional relationship is reported worldwide; however, the underlying reasons for this co-occurrence are unknown. In this review, we summarize the current epidemiologic evidence and putative mechanisms of these metachronous or synchronous cancers. Key potential causative factors are chemotherapy and radiotherapy of the primary tumor, genetic variants linking the two diseases, hormonal signaling both from the thyroid gland and from estrogens, and lifestyle and environmental factors. There is a critical need for additional epidemiologic studies focused on gender and regional incidence together with molecular investigations on common tumorigenic pathways in these endocrine cancers. Understanding the putative mechanisms will aid in the diagnosis and clinical management of both diseases.

Thyroid nodule recurrence following lobo-isthmectomy: incidence, patient's characteristics, and risk factors

PURPOSE

This study was aimed at assessing the incidence and timing of thyroid nodules recurrence, defined as appearance of new benign or malignant nodules in contralateral lobe in patients with benign thyroid nodules or thyroid microcarcinoma treated with lobo-isthmectomy. Patient's characteristics and risk factors associated with this phenomenon were also investigated.

METHODS

A retrospective study was performed by evaluating 413 patients undergoing lobo-isthmectomy with a minimum follow-up of 1 year. Clinical characteristics, surgical interventions and complications, histological diagnosis, and thyroid function at last follow-up were collected.

RESULTS

Single or multiple thyroid nodule recurrence equally occurred in 80 patients (23%) with a median time to relapse of ~ 5 years (range 0.3-34.5 years) after lobo-isthmectomy. Recurrence was significantly associated with younger age (< 46 years) and number of pregnancies in women. Development of hypothyroidism was not rare either (~ 10%) and appeared in 3-19 months; a preoperative TSH level > 2.43 mIU/L was associated with the need of l-thyroxin replacement therapy after surgery. The most frequent surgical complication was transient hypoparathyroidism (4.6%), while the rate of permanent hypoparathyroidism significantly increased in patients submitted to completion thyroidectomy (5.3%).

CONCLUSIONS

Thyroid nodules recurrence following lobo-isthmectomy is not a rare event and occurs within 5 years after surgery, more frequently in younger patients with family history of nodular goiter and in women with multiple pregnancies. Pre-surgical TSH levels may predict the development of post-surgical hypothyroidism, possibly improving the management of patients addressed to surgery.

Aminophenols increase proliferation of thyroid tumor cells by inducing the transcription factor activity of estrogen receptor α

Aminophenols, which are widely used as components of hair dye and medicine, may function as environmental endocrine disruptors by regulating the proliferation of endocrine-related cancers. Estrogen receptor α (ERα) is a key regulator of breast cancer. Recently, it was found that ERα may also participate in the transformation and progression of thyroid tumors, but its interaction with aminophenols and its function in thyroid tumors is not clear. In this study, the transcription factor activity of ERα in BHP10-3 cells (a thyroid tumor cell line) was examined using luciferase assays. The promoter recruitment of ERα was examined using chromatin co-precipitation (ChIP). Additionally, in an in vivo study, BHP10-3 cells were transplanted into nude mice. Upon administration of aminophenols, the transcription factor activity of ERα was significantly increased in BHP10-3 cells, and the recruitment of ERα to the promoter of its target gene was increased. Aminophenols enhanced the in vitro and in vivo proliferation of BHP10-3 cells. By discovering that aminophenols induce the onco-promoting activity of ERα, our study extends the understanding of the function of aminophenols and suggests that ERα is a potential therapeutic target for the treatment of thyroid tumors.

Differentiated thyroid cancer: Why does it affect predominantly women during the reproductive period and have higher incidence of mutual association with breast cancer?

Differentiated thyroid cancer (DTC) is markedly more common in women than men, and its occurrence and risk for poorer prognosis are associated with pregnancy. Further, it is known that there is a high frequency of co-occurrence of DTC and breast cancer. Although the underlying mechanisms that contribute to these phenomena are not entirely clear, 2 hypotheses are proposed here. First, human chorionic gonadotropin (hCG) produced by the placenta may be involved, since hCG has a similar function to stimulate the thyroid as thyroid-stimulating hormone (TSH), the latter of which is known to play a role in causing DTC and may promote breast cancer through the secretion of thyroid hormones (THs). Second, thyrotropin-releasing hormone (TRH), which is stimulated by suckling in the puerperal period, induces the secretion of not only TSH and thus indirectly THs, but also prolactin (PRL), which can accelerate the development of breast cancer. These hypotheses also explain the pregnancy-associated transient increase in breast cancer risk, while inhibition of estrogen by PRL may have a long-term preventive effect on breast cancer. Pregnancy-associated hyperthyroidism may also account for female preponderance of thyroid disease in general as well as tumors in organs that the thyroid hormone targets such as cardiac myxoma and diffuse-type gastric carcinoma.

Thyroid-stimulating hormone is not the primary regulator of thyroid development in euthyroid children and adolescents living in an iodine-replete area

OBJECTIVES

It is known that there are multiple factors which can affect thyroid gland development during childhood and adolescence. Our aim was to investigate this issue by examining the relationships between age, sex, several anthropometric parameters, pubertal status, thyroid function tests, and iodine intake status with thyroid volume (TV) in children and adolescents.

STUDY DESIGN

This was a cross-sectional field study conducted in 11 representative cities and villages of Uzbekistan. Six hundred and ten children and adolescents participated. Anthropometric indices and TV were estimated. In addition, thyroid function tests (TFTs) and urinary iodine excretion (UIE) measures were obtained.

RESULTS

Median UIE was 151 μg/L, thus the studied areas were iodine-sufficient. TFTs fluctuated in both genders during childhood and adolescence and the thyroid growth spurt was observed, in both sexes, at the ages of 12 and 13 years, which coincided with the age of menarche in girls. Thyroid volume was positively correlated with body surface area (BSA) (r = 0.800, p < 0.001), age (r = 0.780, p < 0.001), fat-free mass (FFM) (r = 0.797, p < 0.001) and negatively correlated with serum TSH (r = -0.154, p = 0.05). No association between thyroid volume and UIE was observed.

CONCLUSIONS

In euthyroid children and adolescents living in iodine-replete areas, thyroid gland development appears to follow the pattern of linear growth and displays a growth spurt at the onset of puberty, probably due to the abrupt increase of circulating sex steroids. At this age, TSH does not appear to be the main regulator of thyroid gland development.

Fertility Drugs Associated with Thyroid Cancer Risk: A Systematic Review and Meta-Analysis

Associations have been demonstrated between fertility drugs and a variety of hormone-sensitive carcinomas. The purpose of this study was to determine the relationship between fertility drugs used in the treatment of female infertility and the risk of thyroid cancer. To investigate the clinical significance of fertility drugs used for the treatment of female infertility and the risk associated with thyroid cancer, we performed a literature search using PubMed, MEDLINE, the Cochrane Library, the Web of Science, and EBSCOHOST for comparative studies published any time prior to July 21, 2017. The studies included women who were treated for infertility with fertility drugs, such as clomiphene citrate, gonadotropins, or other unspecified fertility agents, which reported the incidence of thyroid cancer as the main outcome. Eight studies were included in the meta-analyses. Among women with infertility, there was a significant positive association between thyroid cancer risk and the use of fertility drugs (relative risk [RR] = 1.35; 95% confidence interval [CI] 1.12–1.64; P = 0.002). Additionally, among women with infertility, the use of clomiphene citrate was associated with an increased risk of thyroid cancer compared to women who did not use fertility drugs (RR = 1.45; 95% CI 1.12–1.88; P = 0.005). After pooling results, we found that the parity status of infertile women using fertility drugs was not associated with thyroid cancer risk (RR = 0.99; 95% CI 0.61–1.58, P = 0.95). In summary, clomiphene citrate (the most commonly used fertility drug) and other fertility drugs are associated with an increased risk of thyroid cancer.

The role of pregnancy, perinatal factors and hormones in maternal cancer risk: a review of the evidence

An understanding of the origin of cancer is critical for cancer prevention and treatment. Complex biological mechanisms promote carcinogenesis, and there is increasing evidence that pregnancy-related exposures influence foetal growth cell division and organ functioning and may have a long-lasting impact on health and disease susceptibility in the mothers and offspring. Nulliparity is an established risk factor for breast, ovarian, endometrial and possibly pancreatic cancer, whilst the risk of kidney cancer is elevated in parous compared with nulliparous women. For breast, endometrial and ovarian cancer, each pregnancy provides an additional risk reduction. The associations of parity with thyroid and colorectal cancers are uncertain. The timing of reproductive events is also recognized to be important. Older age at first birth is associated with an increased risk of breast cancer, and older age at last birth is associated with a reduced risk of endometrial cancer. The risks of breast and endometrial cancers increase with younger age at menarche and older age at menopause. The mechanisms, and hormone profiles, that underlie alterations in maternal cancer risk are not fully understood and may differ by malignancy. Linking health registries and pooling of data in the Nordic countries have provided opportunities to conduct epidemiologic research of pregnancy exposures and subsequent cancer. We review the maternal risk of several malignancies, including those with a well-known hormonal aetiology and those with less established relationships. The tendency for women to have fewer pregnancies and at later ages, together with the age-dependent increase in the incidence of most malignancies, is expected to affect the incidence of pregnancy-associated cancer.