Incidence of breast carcinoma in women with thyroid carcinoma

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.

Characterization of Lactate Metabolism Score in Breast and Thyroid Cancers to Assist Immunotherapy via Large-Scale Transcriptomic Data Analysis

Breast cancer (BC) and thyroid cancer (TC) have the highest rate of incidence, especially in women. Previous studies have revealed that lactate provides energetic and anabolic support to cancer cells, thus serving as an important oncometabolite with both extracellular and intracellular signaling functions. However, the correlation of lactate metabolism scores with thyroid and breast cancer immune characteristics remains to be systematically analyzed. To investigate the role of lactate at the transcriptome level and its correlation with the clinical outcome of BC and TC, transcriptome data of 1,217 patients with breast cancer (BC) and 568 patients with thyroid cancer (TC) were collected from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets with their corresponding clinical and somatic mutation data. The lactate metabolism score was calculated based on a single-sample gene set enrichment analysis (ssGSEA). The results showed that lactate metabolism-related genes and lactate metabolism scores was significantly associated with the survival of patients with BRCA and THCA. Notably, the lactate metabolism scores were strongly correlated with human leukocyte antigen (HLA) expression, tumor-infiltrating lymphocyte (TIL) infiltration, and interferon (IFN) response in BC and TC. Furthermore, the lactate metabolism score was an independent prognostic factor and could serve as a reliable predictor of overall survival, clinical characteristics, and immune cell infiltration, with the potential to be applied in immunotherapy or precise chemotherapy of BC and TC.

A pathogenic variant in CHEK2 shows a founder effect in Portuguese Roma patients with thyroid cancer

PURPOSE

Germline mutations in DNA repair-related genes have been recently reported in cases with familial non-medullary thyroid carcinoma (FNMTC). A Portuguese family from the Roma ethnic group with four members affected with papillary thyroid carcinoma (PTC), and three members with multinodular goiter (MNG) was identified. The aim of this study was to investigate the involvement of DNA repair-related genes in the etiology of FNMTC in this family and in the Roma ethnic group.

METHODS

Ninety-four hereditary cancer predisposition genes were analyzed through next-generation sequencing. Sanger sequencing was used for variant confirmation and screening. Twelve polymorphic markers were genotyped for haplotype analysis in the CHEK2 locus.

RESULTS

A germline pathogenic frameshift variant in the CHEK2 gene [c.596dupA, p.(Tyr199Ter)] was detected in homozygosity in the proband (PTC) and in his brother (MNG), being heterozygous in his mother (PTC), two sisters (PTC), and one nephew (MNG). This variant was absent in 100 general population controls. The screening of the CHEK2 variant was extended to other Roma individuals, being detected in 2/33 Roma patients with thyroid cancer, and in 1/15 Roma controls. Haplotype segregation analysis identified a common ancestral core haplotype (Hcac), covering 10 Mb in the CHEK2 locus, shared by affected CHEK2 variant carriers. Analysis of 62 individuals CHEK2 wild-type indicated that none presented the Hcac haplotype. The estimated age for this variant suggested that it was transmitted by a relatively recent common ancestor.

CONCLUSIONS

We identified a founder CHEK2 pathogenic variant, which is likely to underlie thyroid cancer and other cancer manifestations in the Roma population.

Breast Cancer After Treatment of Differentiated Thyroid Cancer With Radioiodine in Young Females: What We Know and How to Investigate Open Questions. Review of the Literature and Results of a Multi-Registry Survey

Published studies on the risk of radiation-induced second primary malignancy (SPM) after radioiodine treatment (RAI) of differentiated thyroid cancer (DTC) refer mainly to patients treated as middle-aged or older adults and are not easily generalizable to those treated at a younger age. Here we review available literature on the risk of breast cancer as an SPM after RAI of DTC with a focus on females undergoing such treatment in childhood, adolescence, or young adulthood. Additionally, we report the results of a preliminary international survey of patient registries from academic tertiary referral centers specializing in pediatric DTC. The survey sought to evaluate the availability of sufficient patient data for a potential international multicenter observational case-control study of females with DTC given RAI at an early age. Our literature review identified a bi-directional association of DTC and breast cancer. The general breast cancer risk in adult DTC survivors is low, ~2%, slightly higher in females than in males, but presumably lower, not higher, in those diagnosed as children or adolescents than in those diagnosed at older ages. RAI presumably does not substantially influence breast cancer risk after DTC. However, data from patients given RAI at young ages are sparse and insufficient to make definitive conclusions regarding age dependence of the risk of breast cancer as a SPM after RAI of DTC. The preliminary analysis of data from 10 thyroid cancer registries worldwide, including altogether 6,449 patients given RAI for DTC and 1,116 controls, i.e., patients not given RAI, did not show a significant increase of breast cancer incidence after RAI. However, the numbers of cases and controls were insufficient to draw statistically reliable conclusions, and the proportion of those receiving RAI at the earliest ages was too low.In conclusion, a potential international multicenter study of female patients undergoing RAI of DTC as children, adolescents, or young adults, with a sufficient sample size, is feasible. However, breast cancer screening of a larger cohort of DTC patients is not unproblematic for ethical reasons, due to the likely, at most slightly, increased risk of breast cancer post-RAI and the expected ~10% false-positivity rate which potentially produced substantial "misdiagnosis."

Machine Learning Approach to find the relation between Endometriosis, benign breast disease, cystitis and non-toxic goiter

The exact mechanism of endometriosis is unknown. The recommendation system (RS) based on item similarities of machine learning has never been applied to the relationship between diseases. The study aim was to identify diseases associated with endometriosis by applying RS based on item similarities to insurance data in South Korea. Women aged 15 to 45 years extracted from the Korean Health Insurance Review & Assessment Service National Inpatient Sample (HIRA-NIS) 2009–2015. We used the RS model to extract diseases that were correlated with an endometriosis diagnosis. Among women aged 15 to 45 years, endometriosis was defined as a diagnostic code of N80.x and a concurrent treatment code. A control group was defined as women who did not have the N80.x code. Benign breast diseases, cystitis, and non-toxic goitre were extracted by the RS. A total of 1,730,562 women were selected as the control group, and 11,273 women were selected as the endometriosis group. In logistic regression analysis adjusted for age per 5 years, data year, and socioeconomic status, benign neoplasm of breast (odds ratio (OR): 2.58; 95% confidence interval (CI): 1.90–3.50), other cystitis (OR: 2.63; 95% CI: 1.56–4.44), and non-toxic single thyroid nodule (OR: 1.62; 95% CI: 1.14–2.32) were statistically significant. Endometriosis was associated with benign breast disease, cystitis, and non-toxic goitre.

Iodine stimulates estrogen receptor singling and its systemic level is increased in surgical patients due to topical absorption

Iodine is crucial for thyroid hormone production. However, recent epidemiologic studies have shown that breast cancer patients have an elevated risk of developing thyroid cancer and vice versa. A notable finding in this study is that iodine stimulated the transcriptional activity of estrogen receptor-α (ER-α) in breast cancer cells. Iodine stimulated expression of several ER-α regulated gene including PS2, Cathepsin D, CyclinD1, and PR both in vitro and in nude mice, which is consistent with its stimulation of both anchorage-dependent and -independent growth of ER-α positive breast cancer cells and the effect to dampen tumor shrinkage of MCF-7 xenograft in ovariectomized nude mice. Analyses of clinical urine samples from breast cancer patients undergoing surgery demonstrated that urinary iodine levels were significantly higher than that in controls; and this increased level is due to the antiseptic use of iodine during breast surgery. The present study indicates that excess iodine intake may be an unfavorable factor in breast cancer by stimulation of ER-α transcriptional activity.

Risk of second primary breast cancer after radioactive iodine treatment in thyroid cancer: a systematic review and meta-analysis

The aim of this study was to determine whether the risk of second primary breast cancer (SPBC) is increased in thyroid cancer patients treated with radioactive iodine (RAI). We searched the MEDLINE, EMBASE, and the Cochrane Library and Chinese database for studies that reported the risk of SPBC in thyroid cancer patients treated with RAI and patients not treated with RAI. Two independent reviewers screened citations and reviewed full-text papers. A meta-analysis was carried out using the Review Manager software. Six cohort studies (three from Europe, one from America, and two from east Asia) with 17,914 patients were included in this review. The relative risk of SPBC in thyroid cancer survivors treated with RAI was 0.61 (95% confidence interval 0.47-0.79) relative to thyroid cancer survivors not treated with RAI. The risk of SPBC in thyroid cancer survivors treated with RAI is not increased compared with thyroid cancer survivors not treated with RAI.

Incidence of Nonthyroidal Primary Malignancy and the Association with (131)I Treatment in Patients with Differentiated Thyroid Cancer

BACKGROUND

The occurrence of nonthyroidal primary malignancy (NTPM) and the potential association of with radioiodine (RAI) treatment are important concerns in patients with differentiated thyroid cancer (DTC), but incidence data are conflicting. The aims of the present study were to investigate the incidence of NTPM and its association with RAI treatment in a cohort of DTC patients treated at a single tertiary medical center.

METHODS

The data of 1943 patients with DTC recorded in the Rabin Medical Center Thyroid Cancer Registry were cross-matched with data from the Israeli National Cancer Registry to identify those diagnosed with an NTPM. Patient medical files were reviewed. Second primary malignancy (SPM) was defined as new malignancy diagnosed at least two years after DTC diagnosis.

RESULTS

For 1434 of the 1943 patients (73.8%), the American Joint Committee on Cancer TNM stage was 1-2. The mean follow-up was 9.3 years. Of the 1943 patients, 1574 (81%) were treated with RAI, and 1467 were followed for at least 2 years, and of these, 1145 patients (78%) received a cumulative dose of ≤200 mCi. A total of 409 NTPMs were diagnosed in 368/1943 patients with DTC (18.9%; 265 female, mean age 53.9 ± 15 years), including 173 SPMs (42.3%) in 166/368 patients. The most common NTPM and SPM was breast cancer followed by hematologic malignancies. In patients followed for ≥2 years, SPMs were diagnosed in 9% of RAI-treated patients and 10.5% of non-RAI-treated patients. SPM rates were 10.2% and 7.8% for a cumulative RAI dose of ≤100 mCi and >100 mCi respectively. Hazard ratios for SPM in patients that received/did not receive RAI treatment was 1.27 (95% confidence interval 0.88-1.82; p = 0.1). There was no correlation between first or cumulative RAI dose and diagnosis of SPM.

CONCLUSIONS

NTPMs are not uncommon in patients with DTC and usually antecede the DTC. In a population of mostly low-risk DTC patients, in whom limited activities of RAI are usually administered, this treatment is apparently not associated with an overall increased risk of SPMs compared with subjects not receiving RAI treatment.

Associations between Medical Conditions and Breast Cancer Risk in Asians: A Nationwide Population-Based Study in Taiwan

Background

The breast cancer incidence in Asia is rising. To explore whether the etiology of breast cancer is different from the known risk factors from studies in Western countries, we conducted a nested case-control study using data from the Taiwan National Health Insurance Research Database (NHIRD).

Methods

All medical conditions based on the first three digits of the ICD-9 and a list of medical conditions based on literature review were retrieved for each case and control. The odds ratios (OR) and 95% confidence intervals (CI) of the associations between medical conditions and breast cancer risks were estimated using conditional logistic regression and adjusted for occupation, number of breast cancer screening, and the average number of outpatient visits prior the diagnosis. The associations were also estimated for younger (<50 years old) and older subjects separately.

Results

The analyses included 4,884 breast cancer cases and 19,536 age-matched controls. Prior breast diseases (OR, 95% CI: 2.47, 2.26–2.71), obesity (1.43, 1.04–1.96), endometriosis (1.44, 1.15–1.80), uterine leiomyoma (1.20, 1.03–1.40), hypertensive diseases (1.14, 1.05–1.25), and disorders in lipid metabolism (1.13, 1.04–1.24) were associated with increased breast cancer risk. No heterogeneity was observed between age groups (<50 and ≥50 years old).

Conclusions

In addition to benign breast diseases, obesity, endometriosis, uterine leiomyoma, hypertensive diseases, and disorders of lipid metabolism were associated with a subsequent breast cancer risk.

Impacts

Our results suggest that estrogen related factors may play an important role in breast cancer risks in the Taiwanese female population.

Targeted DNA Sequencing Detects Mutations Related to Susceptibility among Familial Non-medullary Thyroid Cancer

Some studies have demonstrated that familial non-medullary thyroid cancer (FNMTC) has a more aggressive clinical behavior compared to sporadic NMTC (SNMTC). However, FNMTC is difficult to differentiate from SNMTC by the morphology and immunohistochemistry. Although genes responsible for FNMTC were unclear, screening for rare germline mutations on known important tumor suppressor genes might offer more insights on predicting susceptibility to FNMTC. Here, a customized panel was designed to capture all exons of 31 cancer susceptive genes possibly related to FNMTC. Using next-generation sequencing we performed deep sequencing to achieve 500× coverage of the targeted regions. At the end 45 variants were identified in 29 of 47 familial patients and 6 of 16 sporadic patients. Notably, several germline mutations were found matching between paired FNMTC patients from the same family, including APC L292F and A2778S, BRAF D22N, MSH6 G355S and A36V, MSH2 L719F, MEN1 G508D, BRCA1 SS955S, BRCA2 G2508S, and a GNAS inframe insertion. We demonstrated a novel approach to help diagnose and elucidate the genetic cause of the FNMTC patients, and assess whether their family members are exposed to a higher genetic risk. The findings would also provide insights on monitoring the potential second cancers for thyroid cancer patients.

Breast cancer in thyroid cancer survivors: An analysis of the Surveillance, Epidemiology, and End Results-9 database

BACKGROUND

We sought to further elucidate the increased risk for breast cancer among survivors of thyroid cancer.

METHODS

Using the Surveillance, Epidemiology, and End Results-9 database, we conducted a retrospective cohort analysis on women ≥ 18 years of age with breast and thyroid cancer from 1973 to 2011.

RESULTS

A total of 707,678 breast cancer patients and 53,853 thyroid cancer patients were included; 1,750 patients developed breast cancer after a preceding diagnosis of thyroid cancer (T1B). Age-specific risk for breast cancer was greater among thyroid cancer survivors. Incidence trends showed a significant age-time interaction and suggested a difference in thyroid cancer biology as well as a treatment effect. Compared with patients with thyroid cancer only, T1B patients were older with smaller cancers, had more follicular thyroid cancers, and fewer patients received radioactive iodine. T1B patients developed breast cancer earlier than the general population, had more estrogen receptor/progesterone receptor-positive and mixed invasive tumor histology, but smaller tumors, and there is no significant difference in the number of lymph nodes involved or radiation therapy.

CONCLUSION

Thyroid cancer survivors are at greater risk for developing breast cancer than the general population. These patients develop breast cancer early, have more estrogen receptor/progesterone receptor-positive tumors, and have a greater incidence of mixed invasive cancer. Recognition of this association between thyroid and breast cancer should prompt vigilant screening in thyroid cancer survivors and further investigation into the relationship of these 2 diseases.

Radioactive Iodine Therapy Did Not Significantly Increase the Incidence and Recurrence of Subsequent Breast Cancer

CONTEXT

Previous studies on the extent to which radioactive iodine (RAI) therapy for thyroid cancer increases the risk of subsequently developing breast cancer have given conflicting results.

OBJECTIVE

This study aimed to evaluate the effect of RAI treatment on breast cancer development and recurrence among female patients with primary thyroid cancer.

DESIGN

This was a retrospective cohort study. The risk of subsequent breast cancer associated with RAI and its dose in hazard ratios (HRs) with 95% confidential intervals (CIs) were calculated using time-dependent Cox proportional hazard models.

PATIENTS

A total of 6150 patients with thyroid cancer enrolled between 1973 and 2009 were followed until December 2012. Of these, 3631 (59.0%) received RAI therapy. During the follow-up period, 99 primary breast cancers were diagnosed.

MAIN OUTCOME MEASURE

Risk of breast cancer development according to RAI therapy and RAI dose during treatment for primary thyroid cancer.

RESULTS

RAI therapy did not significantly increase the incidence of subsequent breast cancer among female patients (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.22-1.06) when a 2-year latency period was accounted for. High-dose RAI (≥120 mCi) was associated with a reduced incidence of subsequent breast cancer (HR, 0.17; 95% CI, 0.05-0.62) in the cohort with a 2-year latency period.

CONCLUSIONS

The long-term follow-up results of this study suggest that RAI treatment for patients with thyroid cancer may not increase the risk or recurrence of breast cancer.

The prevalence of benign breast diseases in patients with nodular goiter and Hashimoto's thyroiditis

PURPOSE

The evidence regarding association between thyroid disorders and benign and malignant breast diseases is increasing. The studies exploring the relationship between thyroid and breast diseases usually have focused on thyroid autoimmunity and functions in patients with breast pathologies. In this study, we aimed to reveal the frequency of benign breast conditions in patients with nodular thyroid disease (NTD) and Hashimoto's thyroiditis (HT).

METHODS

Seventy-one women with NTD, ninety-five women with HT and seventy-two healthy people as a control group were included in the study. Serum thyroid-stimulating hormone, free triiodothyronine, free thyroxine, and thyroid peroxidase autoantibody levels were measured, and thyroid and breast ultrasonography were performed by a single operator in order to determine thyroid and breast pathology.

RESULTS

Benign breast diseases were detected in 54.9% of patients with NTD, in 47.4% of those with HT, and 29.2% of control group in the study (p < 0.01 for nodular and Hashimoto groups versus control group). Simple cyst was found to be the most frequent pathology among benign breast diseases; fibrocystic changes, mixed lesions, benign solid mass, ductal ectasia, and complex cyst followed it. No significant relation was found regarding thyroid function and autoimmunity in patients diagnosed with benign breast disease (p > 0.05).

CONCLUSIONS

The results of our study support the association between benign breast diseases and thyroid diseases. An important implication of this finding may be demonstration of the necessity of scanning for potential breast pathology in women with nodular or autoimmune thyroid disease in clinical practice.

The association between breast cancer and thyroid cancer: a meta-analysis

Previous studies have suggested an association between breast cancer and thyroid cancer; however, there has not been a formal meta-analysis which collates the existing evidence supporting the hypothesis that breast cancer or thyroid cancer predisposes an individual to developing the other. A systematic search was carried out using PubMed and Medline. We searched for articles containing epidemiological evidence of breast cancer following thyroid cancer and vice versa. Additionally, we searched for articles that included epidemiological data involving the incidence of all second primary malignancies (SPMs) following both breast cancer and thyroid cancer, and compared the datasets. The meta-analysis performed in a total of 18 studies showed that there is a significantly increased risk of developing thyroid cancer as a second primary malignancy of breast cancer (SIR = 1.59, 95 % confidence interval (CI) 1.28-1.99). Additionally, there was marginally increased risk of developing breast cancer as a second primary malignancy of thyroid cancer (SIR = 1.24, 95 % CI 1.16-1.33), compared to the general risk of developing a second primary malignancy following thyroid cancer. The findings suggest that the risk of developing thyroid cancer as a second primary malignancy of breast cancer and vice versa is increased compared to the background risk of developing other SPMs. The risk of developing thyroid cancer after a primary breast cancer was higher than the risk of developing breast cancer as a second primary malignancy of thyroid cancer. This suggests that the effects of treatment-related factors and specific pathological processes of each cancer may contribute to the increased risk rather than common risk factors including genetic factors. Elucidation of the common mechanisms between breast cancer and thyroid cancer will have important implications in both diagnostic and therapeutic management of these cancers. Benefit of thyroid ultrasound screening after breast cancer surgery needs to be assessed.

Three Metachronous Cases of HER2-Positive Breast Cancer Accompanied with Thyroid Cancer

BACKGROUND

Breast carcinoma (BC) and papillary thyroid carcinoma (PTC) occur predominantly in women. Many studies have shown that PTC is common among women with BC. Collision metastases in lymph nodes do occur but are not common.

CASE REPORT

Here we report 3 metachronous cases of BC with PTC. PTC developed after BC in each case. Histology and immunohistochemistry revealed that HER2 status was positive in each BC, and in 1, concurrent metastases of BC and PTC were shown in a lymph node of the left cervical region.

CONCLUSION

From our results, we speculate that women with HER2-positive breast cancer may be at a higher risk for thyroid cancer than other cancers. Finding 2 distinct types of cancer metastasized to 1 lymph node in a patient may, therefore, warrant a high index of suspicion and the use of immunohistochemical stains to differentiate the types of collision tumors.

CHEK2 mutations and the risk of papillary thyroid cancer

Mutations in the cell cycle checkpoint kinase 2 (CHEK2) tumor suppressor gene are associated with multi-organ cancer susceptibility including cancers of the breast and prostate. A genetic association between thyroid and breast cancer has been suggested, however little is known about the determinants of this association. To characterize the association of CHEK2 mutations with thyroid cancer, we genotyped 468 unselected patients with papillary thyroid cancer and 468 (matched) cancer-free controls for four founder mutations of CHEK2 (1100delC, IVS2 + 1G>A, del5395 and I157T). We compared the family histories reported by patients with a CHEK2 mutation to those of non-carriers. A CHEK2 mutation was seen in 73 of 468 (15.6%) unselected patients with papillary thyroid cancer, compared to 28 of 460 (6.0%) age- and sex-matched controls (OR 3.3; p < 0.0001). A truncating mutation (IVS2 + 1G>A, 1100delC or del5395) was associated with a higher risk of thyroid cancer (OR = 5.7; p = 0.006), than was the missense mutation I157T (OR = 2.8; p = 0.0001). CHEK2 mutation carriers reported a family history of breast cancer 2.2 times more commonly than non-carriers (16.4% vs.8.1%; p = 0.05). A CHEK2 mutation was found in seven of 11 women (63%) with multiple primary cancers of the breast and thyroid (OR = 10; p = 0.0004). These results suggest that CHEK2 mutations predispose to thyroid cancer, familial aggregations of breast and thyroid cancer and to double primary cancers of the breast and thyroid.

Unique characteristics and outcomes of patients diagnosed with both primary thyroid and primary renal cell carcinoma

OBJECTIVE

Patients with multiple primary malignancies may exhibit unique clinical characteristics that suggest a common predisposition or lead to different disease management. Given the association of primary thyroid (TC) and renal cell carcinoma (RCC), we characterized the clinicopathologic features of patients treated for both malignancies (TC/RCC).

METHODS

TC/RCC patients were identified through the institutional tumor registry and using data compiled by retrospective chart review. To compare with broader institutional and national cohorts, we examined patients admitted with TC or RCC institution-wide and reviewed the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program for these cancers.

RESULTS

Overall, 51% of patients developed TC before RCC, 27% developed RCC before TC, and 22% were diagnosed within 1 year of each other. The mean age at TC diagnosis was 52 ± 15 (18-77), which was significantly older than institutional TC patients (45 ± 16.5 years, P≤.0001), and the mean age at RCC diagnosis was 59 ± 12 (32-79). The TC/RCC cohort had a balanced sex distribution (51% female) compared with the institutional TC group (67% female, P = .0003) and the institutional RCC group (31% female, P<.0001). Similar age and sex ratio differences were seen when compared with SEER cohorts. In the TC/RCC cohort, 43% of patients developed other cancers (52% of females, 33% of males; P = .04); among the females, 45% developed breast cancer.

CONCLUSION

Individuals who develop both TC and RCC may represent a unique subset of cancer patients. Further prospective research is warranted to explore the unanticipated association with breast cancer in female patients and to investigate a possible common pathogenesis underlying these malignancies.

The molecular etiology and prevention of estrogen-initiated cancers: Ockham's Razor: Pluralitas non est ponenda sine necessitate. Plurality should not be posited without necessity

Elucidation of estrogen carcinogenesis required a few fundamental discoveries made by studying the mechanism of carcinogenesis of polycyclic aromatic hydrocarbons (PAH). The two major mechanisms of metabolic activation of PAH involve formation of radical cations and diol epoxides as ultimate carcinogenic metabolites. These intermediates react with DNA to yield two types of adducts: stable adducts that remain in DNA unless removed by repair and depurinating adducts that are lost from DNA by cleavage of the glycosyl bond between the purine base and deoxyribose. The potent carcinogenic PAH benzo[a]pyrene, dibenzo[a,l]pyrene, 7,12-dimethylbenz[a]anthracene and 3-methylcholanthrene predominantly form depurinating DNA adducts, leaving apurinic sites in the DNA that generate cancer-initiating mutations. This was discovered by correlation between the depurinating adducts formed in mouse skin by treatment with benzo[a]pyrene, dibenzo[a,l]pyrene or 7,12-dimethylbenz[a]anthracene and the site of mutations in the Harvey-ras oncogene in mouse skin papillomas initiated by one of these PAH. By applying some of these fundamental discoveries in PAH studies to estrogen carcinogenesis, the natural estrogens estrone (E1) and estradiol (E2) were found to be mutagenic and carcinogenic through formation of the depurinating estrogen-DNA adducts 4-OHE1(E2)-1-N3Ade and 4-OHE1(E2)-1-N7Gua. These adducts are generated by reaction of catechol estrogen quinones with DNA, analogously to the DNA adducts obtained from the catechol quinones of benzene, naphthalene, and the synthetic estrogens diethylstilbestrol and hexestrol. This is a weak mechanism of cancer initiation. Normally, estrogen metabolism is balanced and few estrogen-DNA adducts are formed. When estrogen metabolism becomes unbalanced, more catechol estrogen quinones are generated, resulting in higher levels of estrogen-DNA adducts, which can be used as biomarkers of unbalanced estrogen metabolism and, thus, cancer risk. The ratio of estrogen-DNA adducts to estrogen metabolites and conjugates has repeatedly been found to be significantly higher in women at high risk for breast cancer, compared to women at normal risk. These results indicate that formation of estrogen-DNA adducts is a critical factor in the etiology of breast cancer. Significantly higher adduct ratios have been observed in women with breast, thyroid or ovarian cancer. In the women with ovarian cancer, single nucleotide polymorphisms in the genes for two enzymes involved in estrogen metabolism indicate risk for ovarian cancer. When polymorphisms produce high activity cytochrome P450 1B1, an activating enzyme, and low activity catechol-O-methyltransferase, a protective enzyme, in the same woman, she is almost six times more likely to have ovarian cancer. These results indicate that formation of estrogen-DNA adducts is a critical factor in the etiology of ovarian cancer. Significantly higher ratios of estrogen-DNA adducts to estrogen metabolites and conjugates have also been observed in men with prostate cancer or non-Hodgkin lymphoma, compared to healthy men without cancer. These results also support a critical role of estrogen-DNA adducts in the initiation of cancer. Starting from the perspective that unbalanced estrogen metabolism can lead to increased formation of catechol estrogen quinones, their reaction with DNA to form adducts, and generation of cancer-initiating mutations, inhibition of estrogen-DNA adduct formation would be an effective approach to preventing a variety of human cancers. The dietary supplements resveratrol and N-acetylcysteine can act as preventing cancer agents by keeping estrogen metabolism balanced. These two compounds can reduce the formation of catechol estrogen quinones and/or their reaction with DNA. Therefore, resveratrol and N-acetylcysteine provide a widely applicable, inexpensive approach to preventing many of the prevalent types of human cancer.

The prognosis and treatment of primary thyroid cancer occurred in breast cancer patients: comparison with ordinary thyroid cancer

PURPOSE

Due to the increased prevalence of thyroid cancer, it has been frequently detected in breast cancer patients recently. The aim of this study was to evaluate the clinicopathologic characteristics of thyroid cancer in breast cancer patients with respect to prognosis and treatment.

METHODS

From August 1998 to September 2012, 101 breast cancer patients were diagnosed with thyroid cancer (BT group). One hundred ninety-three female patients with a thyroid malignancy that underwent thyroidectomy in 2008 were recruited as controls (oT group). The clinicopathologic results of these two groups were compared.

RESULTS

Patients were older (51.40 vs. 47.16, P < 0.001), mean tumor size was smaller (0.96 cm vs. 1.43 cm, P < 0.001), and extrathyroidal extension was less common in the BT group. In both groups, papillary thyroid carcinoma was the most common type of thyroid malignancy. T and N classifications of thyroid cancer were less severe in the BT group, but group TNM stages were similar. Endoscopic thyroid surgery was performed in 12.9% of patients in the BT group and in 6.7% of patients in the oT group. Postoperative radioactive iodine ablation was performed less often in the BT group (P < 0.001). Group recurrence rates were not significantly different.

CONCLUSION

Thyroid cancer in breast cancer patients was diagnosed at earlier status than ordinary thyroid cancer. However, the prognosis of thyroid cancer in breast cancer patients was not superior to that in patients with thyroid cancer alone. Radioactive iodine ablation was performed less often and endoscopic surgery could be performed in breast cancer patients.

Unbalanced estrogen metabolism in thyroid cancer

Well-differentiated thyroid cancer most frequently occurs in premenopausal women. Greater exposure to estrogens may be a risk factor for thyroid cancer. To investigate the role of estrogens in thyroid cancer, a spot urine sample was obtained from 40 women with thyroid cancer and 40 age-matched controls. Thirty-eight estrogen metabolites, conjugates and DNA adducts were analyzed by using ultraperformance liquid chromatography/tandem mass spectrometry and the ratio of adducts to metabolites and conjugates was calculated for each sample. The ratio of depurinating estrogen-DNA adducts to estrogen metabolites and conjugates significantly differed between cases and controls (p < 0.0001), demonstrating high specificity and sensitivity. These findings indicate that estrogen metabolism is unbalanced in thyroid cancer and suggest that formation of estrogen-DNA adducts might play a role in the initiation of thyroid cancer.

Association of thyroid, breast and renal cell cancer: a population-based study of the prevalence of second malignancies

BACKGROUND

Analysis of the National Cancer Institute's Surveillance, Epidemiology, and End Results data has shown that the incidence of thyroid cancer is higher in patients with a preexisting malignancy and that the incidence of other malignancies is higher in patients with thyroid cancer. The purpose of this study was to evaluate the prevalence of a second malignancy in patients treated for thyroid, breast or renal cell cancer and determine what associations, if any, exist between these cancers.

METHODS

This study utilized the novel data system, Explorys, as its population base. Patient cohorts were constructed using ICD-9 codes, and prevalence rates were obtained for each cancer. Rates of second malignancy were obtained and compared to the baseline prevalence for a particular malignancy.

RESULTS

Female thyroid cancer patients had a 0.67- and twofold increase in prevalence of a subsequent breast and renal cell cancer. Female breast and renal cell cancer patients had a twofold and 1.5-fold increase in the prevalence of thyroid cancer, respectively. Male patients with thyroid cancer had a 29- and 4.5-fold increase in prevalence of subsequent breast and renal cell cancer. Male patients with breast and renal cell cancer had an increased prevalence of subsequent thyroid cancer, 19- and threefold, respectively.

CONCLUSIONS

Our study demonstrated a bidirectional association between thyroid, breast and renal cancer in both male and female patients. This may have important implications for patient follow-up and screening after treatment of a primary cancer.

Differentiated thyroid cancer: management of patients with radioiodine nonresponsive disease

Differentiated thyroid carcinoma (papillary and follicular) has a favorable prognosis with an 85% 10-year survival. The patients that recur often require surgery and further radioactive iodine to render them disease-free. Five percent of thyroid cancer patients, however, will eventually succumb to their disease. Metastatic thyroid cancer is treated with radioactive iodine if the metastases are radioiodine avid. Cytotoxic chemotherapies for advanced or metastatic noniodine avid thyroid cancers show no prolonged responses and in general have fallen out of favor. Novel targeted therapies have recently been discovered that have given rise to clinical trials for thyroid cancer. Newer aberrations in molecular pathways and oncogenic mutations in thyroid cancer together with the role of angiogenesis in tumor growth have been central to these discoveries. This paper will focus on the management and treatment of metastatic differentiated thyroid cancers that do not take up radioactive iodine.

Salivary gland malignancy and radioiodine therapy for thyroid cancer

BACKGROUND

The risk of second primary malignancies in patients with well-differentiated thyroid cancer is of special interest because of the common use of radioactive iodine (RAI) ablation and/or treatment of these patients and the theoretical risk of subsequent nonthyroid malignancies associated with the radiation exposure. This brief report focuses specifically on the occurrence of second primary malignancies of the salivary glands. RAI residency within salivary tissues is known to have both acute and chronic consequences on salivary function, but secondary neoplasia is quite unusual.

SUMMARY

We present a very rare case of a patient with papillary thyroid cancer treated with 600 mCi of RAI, who subsequently developed salivary gland cancer.

CONCLUSIONS

We recommend salivary gland protection to diminish potential side effects after the exposure to radioiodine. On the basis of our experience we suggest administration of sialogogues (such as lemon juice) continuously, every 30-60 minutes for 24 hours, after RAI administration.

Iodine alters gene expression in the MCF7 breast cancer cell line: evidence for an anti-estrogen effect of iodine

The protective effects of iodine on breast cancer have been postulated from epidemiologic evidence and described in animal models. The molecular mechanisms responsible have not been identified but laboratory evidence suggests that iodine may inhibit cancer promotion through modulation of the estrogen pathway. To elucidate the role of iodine in breast cancer, the effect of Lugol's iodine solution (5% I(2), 10% KI) on gene expression was analyzed in the estrogen responsive MCF-7 breast cancer cell line. Microarray analysis identified 29 genes that were up-regulated and 14 genes that were down-regulated in response to iodine/iodide treatment. The altered genes included several involved in hormone metabolism as well as genes involved in the regulation of cell cycle progression, growth and differentiation. Quantitative RT-PCR confirmed the array data demonstrating that iodine/iodide treatment increased the mRNA levels of several genes involved in estrogen metabolism (CYP1A1, CYP1B1, and AKR1C1) while decreasing the levels of the estrogen responsive genes TFF1 and WISP2. This report presents the results of the first gene array profiling of the response of a breast cancer cell line to iodine treatment. In addition to elucidating our understanding of the effects of iodine/iodide on breast cancer, this work suggests that iodine/iodide may be useful as an adjuvant therapy in the pharmacologic manipulation of the estrogen pathway in women with breast cancer.

The risk of second primary malignancies up to three decades after the treatment of differentiated thyroid cancer

BACKGROUND

The 10-yr survival rate of patients with differentiated thyroid cancer exceeds 90%. These patients may be at elevated risk for secondary cancers.

METHODS

The risk of nonthyroid second primary malignancies after differentiated thyroid cancer was determined in 30,278 patients diagnosed between 1973 and 2002 from centers participating in the National Cancer Institute's Surveillance, Epidemiology, and End Results program. Median follow-up was 103 months (range, 2-359 months). Risk was further assessed for the addition of radioisotope therapy, gender, latency to development of secondary cancer, and age at thyroid cancer diagnosis.

RESULTS

There were 2158 patients who developed a total of 2338 nonthyroid second primary malignancies, significantly more than that expected in the general population [observed/expected (O/E) = 1.09; 95% confidence interval (CI), 1.05-1.14; P < 0.05; absolute excess risk per 10,000 person-years (AER) = 6.39]. A significantly greater risk of second primary malignancies over that expected in the general population was for patients treated with radioisotopes (O/E = 1.20; 95% CI, 1.07-1.33; AER = 11.8) as well as for unirradiated patients (O/E = 1.05; 95% CI, 1.00-1.10; AER = 3.53). However, the increased risk was greater for the irradiated vs. the unirradiated cohort (relative risk = 1.16; 95% CI, 1.05-1.27; P < 0.05). Gender did not affect risk. The greatest risk of second primary cancers occurred within 5 yr of diagnosis and was elevated for younger patients.

CONCLUSIONS

The overall risk of second primary malignancies is increased for thyroid cancer survivors and varies by radioisotope therapy, latency, and age at diagnosis.

Second primary malignancy risk in thyroid cancer survivors: a systematic review and meta-analysis

OBJECTIVE

To determine the risk of second primary malignancies (SPMs) in thyroid cancer survivors.

DESIGN

We performed a systematic review and meta-analysis examining the standardized incidence ratios (SIRs) of SPMs in thyroid cancer survivors (compared to individuals without thyroid cancer). Two independent reviewers screened citations and reviewed all full-text papers deemed potentially relevant. Final consensus was reached on inclusion of papers in the review. Data were pooled using fixed effects models.

MAIN OUTCOMES

Thirteen full-text papers were included. The incidence of SPMs in thyroid cancer survivors was increased with an SIR of 1.20 (95% confidence interval 1.17, 1.24) (based on pooled data from six studies of 70,844 thyroid cancer survivors). The SIR of the following SPMs was significantly increased: salivary gland, stomach, colon/colorectal, breast, prostate, kidney, brain/central nervous system, soft tissue sarcoma, non-Hodgkin's lymphoma, multiple myeloma, leukemia, bone/joints, and adrenal. A significantly reduced risk of lung and cervical cancers was observed.

CONCLUSIONS

Thyroid cancer survivors are at increased risk of SPMs, which may be related to disease-specific treatments or genetic predisposition.

Increased prevalence of breast cancer among patients with thyroid and parathyroid disease

BACKGROUND

A breast cancer (BC) history was elicited more frequently than expected among thyroid operation patients, which prompted an investigation of risks for concurrent or subsequent nonendocrine malignancies.

METHODS

Of 94,939 patients at a tertiary referral center with breast, thyroid, or parathyroid disease from 2000 to 2006, those patients with more than one tumor type were identified. Rates of BC, thyroid cancer (TC), hyperparathyroidism (HPT), and multiple diagnoses were compared with matched populations using Surveillance, Epidemiology, and End Results (SEER) data.

RESULTS

Of those patients identified, 1604 patients had TC, 12,440 patients had BC, and 1352 patients had HPT. Sixty patients with TC (3.7%) and 70 patients with HPT (5.2%) also had BC. Of 820 consecutive thyroidectomy patients, 23 patients (2.8%) had TC and BC, compared with 1.6% expected from a Monte Carlo distribution using SEER data (P = .001). BC and TC occurred within 5 years in 90% of patients, who tended to be older than those with a single cancer. HPT affected 0.6% of patients with BC, 6% of patients with TC, and 7% of patients with both malignancies.

CONCLUSION

Patients found initially to have TC or BC may be predisposed to develop the other malignancy within a short timeframe. HPT is also more prevalent among these patients. Vigilant screening for associated disorders should accompany initial diagnosis of either cancer.

Seaweed and soy: companion foods in Asian cuisine and their effects on thyroid function in American women

Seaweeds and soy are two commonly eaten foods in Asia. Both have been reported to affect thyroid function, seaweed because of its iodine content and soy because of its goitrogenic effect. Twenty-five healthy postmenopausal women (mean age 58 years) completed a double-blinded randomized crossover study. Ten capsules (5 g/day) of placebo or seaweed (Alaria esculenta), providing 475 microg of iodine/day, were consumed daily for 7 weeks. A powdered soy protein isolate (Solae Co., St. Louis, MO), providing 2 mg of isoflavones/kg of body weight, was given daily during the last week of each treatment arm. On average, this provided 141.3 mg of isoflavones/day and 67.5 g of protein/day. Blood samples and 48-hour urine samples were collected before and after each intervention period, and urinary I/C (microg of iodine/g of creatinine) and serum thyroxine, free thyroxine index, total triiodothyronine, and thyroid stimulating hormone (TSH) were measured. Seaweed ingestion increased I/C concentrations (P < .0001) and serum TSH (P < .0001) (1.69 +/- 0.22 vs. 2.19 +/- 0.22 microU/mL, mean +/- SE). Soy supplementation did not affect thyroid end points. Seven weeks of 5 g/day seaweed supplementation was associated with a small but statistically significant increase in TSH. Soy protein isolate supplementation was not associated with changes in serum thyroid hormone concentrations.

The incidence of second primary tumors in thyroid cancer patients is increased, but not related to treatment of thyroid cancer

OBJECTIVE

The aim of the present study is to assess the prevalence of second primary tumors in patients treated for thyroid cancer. Furthermore, we wanted to assess the standardized risk rates for all second primary tumors, but especially for breast cancer, as data in the literature indicate an excessive risk in differentiated thyroid cancer (DTC) patients for this tumor.

MATERIALS AND METHODS

We included consecutive patients, who received ablation treatment with I-131 at the Leiden University Medical Center between January 1985 and December 1999 (n = 282). The mean period of follow-up was 10.6 +/- 4.1 years.

RESULTS

Thirty-five of the 282 patients (12.4%) had a second primary tumor (SPT), either preceding or following the diagnosis of thyroid cancer. Five other patients had three primary tumors, including DTC. As a result, 40 additional tumors were found in this group, revealing an overall prevalence of 14.2%. Twenty tumors (7.1%) preceded the thyroid cancer with a mean interval of 5.7 years (range: 0.5-22.0 years), whereas 20 tumors (7.1%) occurred after this tumor with a mean interval of 6.7 years (range: 1.0-15.0 years). In 13 female patients, breast cancer was found as SPT. The standardized incidence rate (SIR) for all cancers after the diagnosis of DTC in this study population was not increased (1.13; confidence interval (CI): 0.68-1.69). However, we found an increased SIR of 2.26 (CI: 1.60-3.03) for all cancers either following or preceding DTC, which is mainly caused by a SIR of 3.95 (CI: 2.06-6.45) for breast cancer.

CONCLUSION

Patients with DTC have an overall increased standardized incidence rate for second primary tumors, but not for second primary tumors following I-131 therapy. These findings suggest a common etiologic and/or genetic mechanism instead of a causal relation.

Inherited aspects of papillary thyroid carcinoma

The presence of papillary carcinoma of the thyroid in multiple generations of one kindred is a statistical impossibility as an occurrence of chance. However, traditional and molecular genetic analyses to date have failed to support the notion of a single gene mutation or identify one, in distinct contrast to medullary carcinoma of the thyroid. Findings to date, outside of distinct multicancer syndromes, suggest the interplay of inherited susceptibility and other factors, such as environmental exposures. It is possible that the main identifiable genetic risk factors at this time are the presence of multinodular goiter or Hashimoto's thyroiditis within the family.

Familial nonmedullary thyroid carcinoma

BACKGROUND

Nonmedullary thyroid carcinomas (NMTCs) originate from the thyroid epithelial cells and, until recently, were thought to arise sporadically without an inherited genetic predisposition. However, evidence of a familial predisposition to NMTC is accumulating.

METHODS

This review addresses the strengths, weaknesses, and clinical implications of the observations indicating an inherited genetic predisposition to NMTC. These observations include epidemiologic studies, descriptions of large kindreds, and genetic analyses.

RESULTS

Familial NMTC (FNMTC) may be caused by an inherited genetic predisposition and can be divided into two groups. The first group has an increased prevalence of NMTC within a familial cancer syndrome with a preponderance of nonthyroidal tumors. In the second group the predominant neoplasm is NMTC, although other neoplasms may occur with increased frequency. These disorders are the focus of this review.

CONCLUSIONS

A family history in NMTC patients should be directed at detecting those familial tumor syndromes with a preponderance of NMTC as well as those familial tumor syndromes enriched in NMTC but with a preponderance of nonthyroidal tumors. Since the recurrence rates may be greater in FNMTC than in sporadic NMTC, careful monitoring is indicated for affected individuals. The advantages and disadvantages of screening asymptomatic members of FNMTC kindreds with thyroid ultrasound are discussed, and the final decision is deferred to the treating physicians and their patients. It is hoped that positional cloning research will identify the FNMTC susceptibility genes.

Radiotherapy for primary thyroid cancer as a risk factor for second primary cancers

Although radiation is considered a risk factor for thyroid cancer, the potential relationship between radiation therapy and the risk of second primary cancer among patients with first primary thyroid cancer has not been evaluated. We identified 26,639 patients with first primary thyroid cancer in the Surveillance, Epidemiology, and End Results (SEER) database from 1973 to 2000. Information on radiation therapy as well as second primary cancers was recorded in SEER. The proportional hazards model was utilized to estimate adjusted risk ratios (RRs) and their 95% confidence intervals (CIs) to assess the potential association between radiation therapy for thyroid cancer and the risk of second primary cancers. With 270,674.33 person-years of follow-up, 1,896 (7.1%) of the 26,639 patients with first primary thyroid cancer developed second primary cancers. Among the second primaries, 35 occurred in the thyroid. No obvious association was observed between radiation therapy and the overall risk of second primary cancer after ten years of follow-up (RR=1.07, 95% CI=0.88-1.30). However, an increased risk was seen for several cancers, including upper digestive system cancers (RR=1.66, 95% CI=1.07-2.57) and myeloid malignancies (RR=3.26, 95% CI=1.39-7.67). Radiation therapy was associated with reduced second cancer risks for thyroid cancer (RR=0.18, 95% CI=0.04-0.76). Beam radiation might be important to the digestive system, radioactive implants might be associated with the male genital system, radioisotopes might have an effect on myeloid malignancies, and combined beam radiation with radioactive implants or radioisotopes might be related to the increased risk of respiratory system cancers. This study suggests that radiation therapy for patients with first primary thyroid cancer might be associated with an increased risk of developing a second primary cancer in the upper digestive system and second primary myeloid malignancies. Radiation therapy for adult patients with thyroid cancer might be associated with a reduced risk of second primary thyroid cancer.

Risk of second primary malignancies in women with papillary thyroid cancer

Second malignancies in women diagnosed with thyroid cancer are of concern given the young average age at diagnosis and excellent survival. Data from the California Cancer Registry were used to evaluate the risk of second primary cancers among a retrospective population-based cohort of 10,932 women diagnosed with papillary thyroid cancer between 1988 and 1999. Follow-up was calculated from 2 months until the diagnosis of a second primary cancer, death, loss to follow-up, or December 31, 1999, whichever occurred first. Standardized incidence ratios, based on age-specific cancer incidence rates for California women, were calculated. During a total of 50,938 person-years of follow-up (mean: 4.7 years), 279 women developed a second primary cancer. The incidence of invasive breast cancer was not elevated compared with California women overall (standardized incidence ratio (SIR) = 0.9, 95% confidence interval (CI): 0.7, 1.1) or when stratified by age, race/ethnicity, follow-up, or radiation treatment. An excess of in situ breast cancer (SIR = 1.6, 95% CI: 1.0, 2.4), kidney cancer (SIR = 3.9, 95% CI: 2.2, 6.3), and melanoma (SIR = 2.1, 95% CI: 1.3, 3.2) limited to the first 5 years after diagnosis was observed. Women with papillary thyroid cancer are at increased risk of in situ, but not invasive, breast cancer, kidney cancer, and melanoma.

Thyroid cancer and multiple primary tumors in the SEER cancer registries

Thyroid cancer incidence rates have increased steadily in the United States and elsewhere. Radiation exposure at a young age is a strong risk factor, but otherwise the etiology is unclear. To explore etiologic clues, we studied the risk of thyroid cancer after an earlier primary cancer, as well as the risk of developing multiple primaries after an earlier thyroid cancer in the U.S. Surveillance, Epidemiology and End-Results (SEER) cancer registries program (1973-2000). In 2,036,597 patients diagnosed with any invasive cancer who survived for a minimum of 2 months, we observed a 42% increased risk compared to the general population for second thyroid cancer based on 1,366 cases (95% confidence interval (CI) = 35-50%; excess absolute risk (EAR) = 0.38/10,000 person-years (PY)). Elevated risks were observed after most cancer sites studied. The most pronounced excess (observed/expected (O/E) = 2.86) was seen for second thyroid cancers detected in the year after diagnosis of the first cancer. Among 29,456 2-month thyroid cancer survivors, 2,214 second cancers occurred (O/E = 1.11, 95% CI = 1.06-1.15; EAR = 7.64/10,000 PY). Again, the highest risk was seen in the first year (O/E = 1.26). Patients <40 years of age at diagnosis of thyroid cancer had a 39% increased risk of a second cancer, whereas for older patients the risk was elevated 6%. We observed consistently increased risks for cancers of the breast, prostate, and kidney, and a likely radiation treatment-related excess of leukemia. Based on small numbers of cases, cancers of the salivary glands, trachea, scrotum, adrenal glands, and brain and central nervous system (CNS) also occurred in excess. A decreased risk was observed for smoking-related malignancies. Thyroid cancer is associated with primary cancers of many different organs. Although enhanced medical surveillance likely plays a role, 2-way, positive associations between thyroid cancer and cancers of the breast, prostate, kidney, salivary glands, brain and CNS, scrotum, and leukemia suggest etiologic similarities and possible treatment effects.

A Case of Bilateral Breast Cancer and Graves’ Disease

We report a case of bilateral breast cancer associated with Graves’ disease characterized by a large goiter and complicated by a severe ophthalmopathy. The hyperthyroidism was treated initially with methimazole and then with thyroidectomy, the ophthalmopathy with intravenous steroids combined with orbital radiotherapy. The breast tumors underwent surgical resection followed by chemotherapy. We describe this case because of the well-known association between breast cancer and thyroid disease, particularly of the autoimmune type, the causes of this being still unclear. Recent literature on this topic is reviewed, discussing the possible role of the Na+-I− symporter and anti-TPO antibodies.

Combined effects of glutathione S-transferase polymorphisms and thyroid cancer risk

Since exposure to ionizing radiation, a risk factor for thyroid cancer, may produce genotoxins potentially eliminated by glutathione-S-transferases, we conducted a case control study to evaluate the role of the GSTM1- and GSTT1-null genotypes and GSTP1 polymorphisms in thyroid cancer. The frequency of GSTP1 Ile/Ile, GSTM1-, and GSTT1-null genotypes was increased in cancer patients when compared with control population. Considering the genotypes over-represented in thyroid cancer patients as potential risk genotypes, we carried out an odds ratio (OR) analysis considering the presence of none, one, two, or three risk genotypes. The results obtained showed that the presence of three potentially risk alleles (GSTM1 null, GSTT1 null, and GSTP1 Ile/Ile) lead to a significant OR increase for all the cases, irrespective of the type of tumor (OR=2.91), for papillary (OR=3.64) but not for follicular tumors. The presence of GSTP1 Ile/Ile leads to a significant later age of tumor onset when compared with GSTP1 Ile/Val and Val/Val (P<0.05), suggesting a possible association between GSTP1 Ile/Ile and the age of disease manifestation. These results suggest that combined GST polymorphisms lead to a moderate increased risk for thyroid cancer, especially for the papillary type, and GSTP1 polymorphisms might modulate the age of onset of the disease.

Second primary malignancies in thyroid cancer patients

The late health effects associated with radioiodine (¹³¹I) given as treatment for thyroid cancer are difficult to assess since the number of thyroid cancer patients treated at each centre is limited. The risk of second primary malignancies (SPMs) was evaluated in a European cohort of thyroid cancer patients. A common database was obtained by pooling the 2-year survivors of the three major Swedish, Italian, and French cohorts of papillary and follicular thyroid cancer patients. A time-dependent analysis using external comparison was performed. The study concerned 6841 thyroid cancer patients, diagnosed during the period 1934–1995, at a mean age of 44 years. In all, 17% were treated with external radiotherapy and 62% received ¹³¹I. In total, 576 patients were diagnosed with a SPM. Compared to the general population of each of the three countries, an overall significantly increased risk of SPM of 27% (95% CI: 15–40) was seen in the European cohort. An increased risk of both solid tumours and leukaemias was found with increasing cumulative activity of ¹³¹I administered, with an excess absolute risk of 14.4 solid cancers and of 0.8 leukaemias per GBq of ¹³¹I and 10⁵ person-years of follow-up. A relationship was found between ¹³¹I administration and occurrence of bone and soft tissue, colorectal, and salivary gland cancers. These results strongly highlight the necessity to delineate the indications of ¹³¹I treatment in thyroid cancer patients in order to restrict its use to patients in whom clinical benefits are expected.

Double primary cancers of the breast and thyroid in women: molecular analysis and genetic implications

Multiple primary cancers are characteristic of hereditary cancer syndromes. A familial association between breast and thyroid cancer has been suggested, but a genetic basis for this association has not yet been established. To determine the extent to which double primary cancers of the breast and thyroid are due to common hereditary factors, we conducted a registry- and hospital-based study in Ontario and Quebec. We obtained family histories of 74 women diagnosed with both cancer of the breast and thyroid before 70 years of age. Cancer histories were obtained for the 533 first- degree relatives of these women. The observed cancer rate in the relatives was compared with the expected number, based on age- standardized Canadian cancer incidence rates, and relative risks were estimated. A total of 87 cancers were observed in the relatives, compared to 93.7 expected cancers, giving a relative risk of 0.9 (95% confidence interval (CI): 0.7-1.1). The risk for breast cancer was 1.1 (95% CI: 0.6-1.7) and the risk for thyroid cancer was 0.7 (95% CI: 0-3.8). Blood samples were collected on 53 patients for mutational analysis of the BRCA1, BRCA2, and PTEN genes. One woman was found to be a carrier of a BRCA1 mutation (exon 11 3227delT). Our findings do not support the hypothesis that a significant proportion of double primary cancers of the breast and thyroid are due to hereditary factors.

The risk of multiple primary breast and thyroid carcinomas

BACKGROUND

Some studies have suggested that there is an association between breast carcinoma and thyroid carcinoma. Because ionizing radiation is a well known risk factor for breast and thyroid carcinomas, the authors studied the effect of the radiation dose delivered for the treatment of each of these two malignancies on the risk of subsequently developing the other malignancy.

METHODS

The risk of developing thyroid carcinoma subsequent to treatment for breast carcinoma was analyzed in 8 patients (cases) and 192 matched control patients (controls) nested in a cohort of 7711 women who were treated at Institut Gustave Roussy between 1954 and 1983. The risk of developing breast carcinoma after treatment for thyroid carcinoma was studied in a cohort of 2365 women who were treated in 3 French cancer centers between 1934 and 1995.

RESULTS

Six of 8 patients with breast carcinoma (75%) who developed thyroid carcinoma and 71% of patients in the control group received radiation therapy during their treatment. The median dose to the thyroid was 6.6 grays (Gy) in the case group and 9.4 Gy in the control group. The overall relative risk of thyroid carcinoma associated with radiation therapy was 1.2 (95% confidence interval, 0.2-6.2). No relation was observed between the radiation dose and the risk of thyroid carcinoma (P = 0.8). Among 2365 women who were treated for thyroid carcinoma, 48 women developed a subsequent breast carcinoma. A significant excess of breast carcinoma was observed among women younger than 59 years at the time of diagnosis of breast carcinoma compared with women in the same age group in the general population. The mean absorbed dose delivered to the breasts by (131)I and external radiation therapy was 0.7 Gy. No relation was found between the radiation dose and the risk of breast carcinoma (P = 0.8).

CONCLUSIONS

The previously reported excess incidence of breast carcinoma after thyroid carcinoma was not related to radiation treatment with (131)I and/or external radiation therapy. Radiation therapy for breast carcinoma did not increase the risk of subsequent thyroid carcinoma.

Cancers among Residents Downwind of the Hanford, Washington, Plutonium Production Site

A community-based health survey for the time period between 1944 and 1995 was collected from 801 individuals who had lived downwind of the U.S. plutonium production facility located in Hanford, Washington. The results of the survey revealed high incidences of all cancers, including thyroid cancer. There were greater than expected numbers of central nervous system tumors and cancers that invaded the female reproductive system (e.g., cancers of the uterus, ovary, cervix, and breast). The authors argue that the greater-than-expected numbers found cannot be accounted for by selection bias alone. Comparisons of crude incidence rates, as well as of occurrence ratios between pairs of cancer types among Downwinders and reasonably similar populations, suggested that the excess neoplasms may be associated with radioactive contamination of food, water, soil, and/or air. In addition, a synergistic effect may exist with agricultural toxins. Previously neglected biophysical and physiological properties of internally lodged, long-lived 129I may be a significant etiological factor in the development of thyroid diseases, including cancer, and other malignancies in exposed populations.

Upper-extremity sarcomas in the United States: analysis of the surveillance, epidemiology, and end results database, 1973-1998

PURPOSE

Upper-extremity soft-tissue sarcomas are a rare disease with unclear epidemiology and evolving treatment strategies. Our purpose is to evaluate the incidence of upper-extremity soft-tissue sarcomas and the use of adjuvant radiotherapy in this patient population.

METHODS

Using the Surveillance, Epidemiology, and End Results (SEER) database, a national population-based database, we identified all cases of primary upper-extremity sarcoma reported to the 9 national SEER registries in the Untied States from 1973 to 1998.

RESULTS

Of the 1,286 upper-extremity soft-tissue sarcomas the average incidence rate is 2.2 cases/million/y, which has not changed significantly from 1973 to 1998. Caucasians' average incidence rate is significantly higher than African Americans' (incidence rate ratio [IRR] = 1.3, p =.02); and men are at a significantly higher risk compared with women (IRR = 1.3, p <.01). The use of adjuvant radiotherapy has increased significantly from 17% in 1973 to 47% in 1998 (p <.01). African-Americans, compared with Caucasians, are significantly less likely to receive adjuvant radiotherapy (odds ratio [OR] =.5, p =.01).

CONCLUSIONS

The incidence of upper-extremity sarcomas has not changed significantly over the past 3 decades; however, the disease differentially affects the population with higher rates in Caucasians and men. Based on the results of this study the use of adjuvant radiotherapy is increasing but African Americans are less likely than Caucasians to receive this treatment for upper-extremity sarcoma.

Thyroid carcinoma

Thyroid carcinomas are fairly uncommon and include disease types that range from indolent localised papillary carcinomas to the fulminant and lethal anaplastic disease. Several attempts to formulate a consensus about treatment of thyroid carcinoma have resulted in published guidelines for diagnosis and initial disease management. Multimodality treatments are widely recommended, although there is little evidence from prospective trials to support this approach. Surgical resection to achieve local disease control remains the cornerstone of primary treatment for most thyroid cancers, and is often followed by adjuvant radioiodine treatment for papillary and follicular types of disease. Thyroid hormone replacement therapy is used not only to rectify postsurgical hypothyroidism, but also because there is evidence to suggest that high doses that suppress thyroid stimulating hormone prevent disease recurrence in patients with papillary or follicular carcinomas. Treatment for progressive metastatic disease is often of limited benefit, and there is a pressing need for novel approaches in treatment of patients at high risk of disease-related death. In families with inherited thyroid cancer syndromes, early diagnosis and intervention based on genetic testing might prevent poor disease outcomes. Care should be carefully coordinated by members of an experienced multidisciplinary team, and patients should be provided with education about diagnosis, prognosis, and treatment options to allow them to make informed contributions to decisions about their care.

Breast cancer among young African-American women: a summary of data and literature and of issues discussed during the Summit Meeting on Breast Cancer Among African American Women, Washington, DC, September 8-10, 2000

BACKGROUND

African-American women younger than age 45 years have a higher risk of incidence and mortality due to breast cancer than other women. The reason for this disparity in risk is not well understood.

METHODS

This review summarizes the literature on the topic of breast cancer in young women and presents a summary of a discussion on this topic during a national forum on breast cancer among African-American women.

RESULTS

The occurrence of breast cancer among African-American women younger than the age of 45 years has not been well studied. There is a clear and long-term pattern of higher incidence and mortality and poorer survival in this population subgroup.

CONCLUSION

Research is needed to understand the reasons for these disparities and to reduce or eliminate them. Studies focused on hormonal factors, genetic factors, diet and obesity, and timely access to state-of-the-art prevention, information, screening, diagnosis, and treatment are likely to produce important new knowledge in this area.

The association of benign and malignant ovarian adenofibromas with breast cancer and thyroid disorders

An unexpected association with breast cancer and thyroid disorders was found during a review of 91 cases of benign and malignant ovarian adenofibromas. Sixty-three tumors were benign, 11 had areas of borderline neoplasms, and 17 had a component of carcinoma. Such tumors were divided into glandular/cystic (61 cases) and papillary (30 cases) according to their gross and microscopic appearance. Among the 61 patients with glandular/cystic adenofibromas, 13 (21%) had breast cancer and 19 (31%) also had thyroid disorders. Among the 30 patients with papillary adenofibromas there were no cases of breast cancer and only 2 patients had thyroid disorders. The average age of the patients with ovarian adenofibroma and breast cancer or thyroid disorders was higher (66 years) than that of patients without breast cancer or thyroid disorders (55 years). More patients with breast cancer and thyroid disorders had bilateral adenofibromas than patients without breast cancer or thyroid disorders. We also reviewed the medical records of 100 patients with ovarian cancer without adenofibroma component, 100 patients with breast cancer, and 100 patients with ovarian and breast cancer. Six percent of patients with ovarian cancer had breast cancer and 16% of each one of these groups had thyroid disorders. This unexpected association found between glandular/cystic adenofibromas, breast cancer, and thyroid disorders might be explained by defects common to these organs. Disorders of some of these organs have been linked by common genetic changes and it is known that these organs are under the influence of similar hormones. Mutations of PTEN have been found in breast and thyroid cancer. The thyroid and ovaries are controlled by glycoprotein hormones of the pituitary gland, which have common alpha subunits.