Radiation exposure and thyroid cancer: a review Iglesias, Maria Laura; Schmidt, Angelica; Ghuzlan, Abir Al ...
Archives of endocrinology and metabolism,
03/2017, Letnik:
61, Številka:
2
Journal Article
Odprti dostop
The association between radiation exposure and the occurrence of thyroid cancer has been well documented, and the two main risk factors for the development of a thyroid cancer are the radiation dose ...delivered to the thyroid gland and the age at exposure. The risk increases after exposure to a mean dose of more than 0.05-0.1 Gy (50-100mGy). The risk is more important during childhood and decreases with increased age at exposure, being low in adults. After exposure, the minimum latency period before the appearance of thyroid cancers is 5 to 10 years. Papillary carcinoma (PTC) is the most frequent form of thyroid carcinoma diagnosed after radiation exposure, with a higher prevalence of the solid subtype in young children with a short latency period and of the classical subtype in cases with a longer latency period after exposure. Molecular alterations, including intra-chromosomal rearrangements, are frequently found. Among them, RET/PTC rearrangements are the most frequent. Current research is directed on the mechanism of genetic alterations induced by radiation and on a molecular signature that can identify the origin of thyroid carcinoma after a known or suspected exposure to radiation.
Background:
Recurrence of adrenocortical carcinoma (ACC) even after complete (R0) resection occurs frequently.
Objective:
The aim of this study was to identify markers with prognostic value for ...patients in this clinical setting.
Design, Setting, and Participants:
From the German ACC registry, 319 patients with the European Network for the Study of Adrenal Tumors stage I–III were identified. As an independent validation cohort, 250 patients from three European countries were included.
Outcome Measurements and Statistical Analysis:
Clinical, histological, and immunohistochemical markers were correlated with recurrence-free (RFS) and overall survival (OS).
Results:
Although univariable analysis within the German cohort suggested several factors with potential prognostic power, upon multivariable adjustment only a few including age, tumor size, venous tumor thrombus (VTT), and the proliferation marker Ki67 retained significance. Among these, Ki67 provided the single best prognostic value for RFS (hazard ratio HR for recurrence, 1.042 per 1% increase; P < .0001) and OS (HR for death, 1.051; P < .0001) which was confirmed in the validation cohort. Accordingly, clinical outcome differed significantly between patients with Ki67 <10%, 10–19%, and ≥20% (for the German cohort: median RFS, 53.2 vs 31.6 vs 9.4 mo; median OS, 180.5 vs 113.5 vs 42.0 mo). Using the combined cohort prognostic scores including tumor size, VTT, and Ki67 were established. Although these scores discriminated slightly better between subgroups, there was no clinically meaningful advantage in comparison with Ki67 alone.
Conclusion:
This largest study on prognostic markers in localized ACC identified Ki67 as the single most important factor predicting recurrence in patients following R0 resection. Thus, evaluation of Ki67 indices should be introduced as standard grading in all pathology reports of patients with ACC.
Cyclophosphamide–dacarbazine–vincristine regimen is recommended for the treatment of malignant pheochromocytoma and paraganglioma (MPP); however, dacarbazine is the only recognized active drug in ...neuroendocrine tumours. We investigated the therapeutic benefit of temozolomide (TMZ), an oral alternative to dacarbazine, in patients with MPP. This is a retrospective study of consecutive patients with documented progressive MPP. We examined the correlation between Succinate dehydrogenase B (SDHB) mutation and O(6)‐methylguanine‐DNA methyltransferase (MGMT) promoter methylation and MGMT expression in the French nation‐wide independent cohort of 190 pheochromocytomas or paragangliomas (PP). Progression‐free survival (PFS) according to RECIST 1.1 and PERCIST 1.0 criteria was the primary end point. Fifteen consecutive patients with MPP were enrolled; ten (67%) carried a mutation in SDHB. The mean dose intensity of TMZ was 172 mg/m2/d for 5 days every 28 days. Median PFS was 13.3 months after a median follow‐up of 35 months. There were five partial responses (33%), seven stable (47%) and three progressive diseases (20%). Grade 3 toxicities were lymphopenia in two patients and hypertension in one. Partial responses were observed only in patients with mutation in SDHB. MGMT immunohistochemistry was negative in tumour samples from four patients who responded to treatment. SDHB germline mutation was associated with hypermethylation of the MGMT promoter and low expression of MGMT in 190 samples of the French nation‐wide independent cohort. This study demonstrates that TMZ is an effective antitumour agent in patients with SDHB‐related MPP. The silencing of MGMT expression as a consequence of MGMT promoter hypermethylation in SDHB‐mutated tumours may explain this finding.
What's New?
Malignant pheochromocytoma and paraganglioma (MPP) are frequently associated with mutations in succinate dehydrogenase B (SDHB) gene. In this study of MPP, the authors found a correlation between SDHB mutations in MPP and hypermethylation of the promoter of O6‐methylguanine‐DNA methyltransferase (MGMT) gene. Hypermethylation and decreased expression of MGMT have been associated with a positive response to the drug temozolomide (TMZ). When the authors tested TMZ in MPP patients, 67% experienced clinical benefit, and 80% of responders had tumors with low levels of MGMT. These results suggest that a personalized therapeutic approach may be applicable to this rare cancer.
Ionizing radiation (IR) causes not only acute tissue damage, but also late effects in several cell generations after the initial exposure. The thyroid gland is one of the most sensitive organs to the ...carcinogenic effects of IR, and we have recently highlighted that an oxidative stress is responsible for the chromosomal rearrangements found in radio-induced papillary thyroid carcinoma. Using both a human thyroid cell line and primary thyrocytes, we investigated the mechanism by which IR induces the generation of reactive oxygen species (ROS) several days after irradiation. We focused on NADPH oxidases, which are specialized ROS-generating enzymes known as NOX/DUOX. Our results show that IR induces delayed NADPH oxidase DUOX1-dependent H ₂O ₂ production in a dose-dependent manner, which is sustained for several days. We report that p38 MAPK, activated after IR, increased DUOX1 via IL-13 expression, leading to persistent DNA damage and growth arrest. Pretreatment of cells with catalase, a scavenger of H ₂O ₂, or DUOX1 down-regulation by siRNA abrogated IR-induced DNA damage. Analysis of human thyroid tissues showed that DUOX1 is elevated not only in human radio-induced thyroid tumors, but also in sporadic thyroid tumors. Taken together, our data reveal a key role of DUOX1-dependent H ₂O ₂ production in long-term persistent radio-induced DNA damage. Our data also show that DUOX1-dependent H ₂O ₂ production, which induces DNA double-strand breaks, can cause genomic instability and promote the generation of neoplastic cells through its mutagenic effect.
Significance Increasing evidence supports the role of chronic oxidative stress in late radiation-induced effects, including malignancy and genetic instability. To date, elevated levels of reactive oxygen species (ROS) have been considered a cause of persistent instability, but until now the mechanism(s) underlying the perpetuation of ROS generation in irradiated cells and their progeny was undetermined. Cells can produce ROS through activation and/or induction of NADPH oxidases. The present investigation identifies the DUOX1-based NADPH oxidase as a ROS-generating system induced after irradiation, causing delayed DNA breakage. Overexpression of DUOX1 in radio-induced thyroid tumors suggests that DUOX1 may contribute to a chronic oxidative stress promoting genomic instability and tumorigenesis.
Anaplastic thyroid carcinoma (ATC) is a rare and undifferentiated form of thyroid cancer. Its prognosis is poor: the median overall survival (OS) of patients varies from 4 to 10 months after ...diagnosis. However, a doubling of the OS time may be possible owing to a more systematic use of molecular tests for targeted therapies and integration of fast-track dedicated care pathways for these patients in tertiary centers. The diagnostic confirmation, if needed, requires an urgent biopsy reread by an expert pathologist with additional immunohistochemical and molecular analyses. Therapeutic management, defined in multidisciplinary meetings, respecting the patient's choice, must start within days following diagnosis. For localized disease diagnosed after primary surgical treatment, adjuvant chemo-radiotherapy is recommended. In the event of locally advanced or metastatic disease, the prognosis is very poor. Treatment should then involve chemotherapy or targeted therapy and decompressive cervical radiotherapy. Here we will review current knowledge on ATC and provide perspectives to improve the management of this deadly disease.
Abstract
Context
Pheochromocytomas and paragangliomas (PPGL) are rare neuroendocrine tumors that are frequently associated with succinate dehydrogenase (SDH) germline mutations. When mutated, SDH ...losses its function, thus leading to succinate accumulation.
Objective
In this study, we evaluated serum succinate levels as a new metabolic biomarker in SDHx-related carriers.
Methods
Retrospective monocentric study of 88 PPGL patients (43 sporadic, 35 SDHB, 10 SDHA/C/D), 17 tumor-free familial asymptomatic carriers (13 SDHB, 4 SDHC/D), and 60 healthy controls. Clinical, biological, and imaging data were reviewed. Serum succinate levels (n = 280) were quantified by an ultra-performance liquid chromatography coupled to a tandem mass spectrometry method and correlated to SDHx mutational status, disease extension, and other biological biomarkers.
Results
Serum succinate levels > 7 μM allowed identification of tumor-free asymptomatic SDHB-mutated cases compared to a healthy control group (100% specificity; 85% sensitivity). At PPGL diagnosis, SDHB-mutated patients had a significantly increased median succinate level (14 μM) compared to sporadic patients (8 μM) (P < 0.01). Metastatic disease extension was correlated to serum succinate levels (r = 0.81). In the SDHB group, patients displaying highest tumor burdens showed significant increased succinate levels compared to the sporadic group (P < 0.0001).
Conclusions
In this pilot study, we showed that serum succinate level is an oncometabolic biomarker that should be useful to identify SDHB-related carriers. Succinate levels are also a marker of metabolic tumor burden in patients with a metastatic PPGL and a potential marker of treatment response and follow-up.
The presence of extrathyroidal extension (ETE) is generally considered as an indication for total thyroidectomy for differentiated thyroid cancer. The accuracy of neck ultrasound for the diagnosis of ...ETE is controversial. The aim of this study was to assess the diagnostic accuracy of preoperative ultrasound evaluation of ETE.
The retrospective and observational study of consecutive patients operated between 2016 and 2019 for cytologically suspicious or indeterminate thyroid nodules were analyzed. US images obtained preoperatively were retrospectively reviewed to identify signs of minimal or gross ETE. Histology was considered as the golden standard for diagnosis of ETE. The sensitivity, specificity, positive (PPV) and negative predictive values (NPV), and accuracy of US were evaluated.
A cohort of 305 patients (75% females, median age 48 years) with 378 nodules (median size 18 mm) was studied. Seventy-five percent of the nodules (n = 228) were malignant on histology and ETE was present in 106 cases (28%): 83 minimal ETE and 23 gross ETE. Suspicion of minimal ETE on preoperative ultrasound was found in 50 (13%) with a sensitivity of 30%, a specificity of 93%, a PPV of 62% and an NPV of 78%, with an accuracy of 76%. Gross ETE on ultrasound was found in 19 (5%) nodules with a sensitivity of 78%, a specificity of 99.7% a PPV of 94.7% an NPV of 98.6% and an accuracy of 98%.
Preoperative US is very specific and accurate in diagnosing gross ETE which impacts the extent of initial surgery for thyroid cancers.
A relationship between the increased density of tumor-associated macrophages (TAMs) and decreased survival was recently reported in thyroid cancer patients. Among these tumors, anaplastic thyroid ...cancer (ATC) is one of the most aggressive solid tumors in humans. TAMs (type M2) have been recognized as promoting tumor growth. The purpose of our study was to analyze with immunohistochemistry the presence of TAMs in a series of 27 ATC.
Several macrophages markers such as NADPH oxidase complex NOX2-p22phox, CD163 and CD 68 were used. Immunostainings showed that TAMs represent more than 50% of nucleated cells in all ATCs. Moreover, these markers allowed the identification of elongated thin ramified cytoplasmic extensions, bestowing a "microglia-like" appearance on these cells which we termed "Ramified TAMs" (RTAMs). In contrast, cancer cells were totally negative. Cellular stroma was highly simplified since apart from cancer cells and blood vessels, RTAMs were the only other cellular component. RTAMs were evenly distributed and intermingled with cancer cells, and were in direct contact with other RTAMs via their ramifications. Moreover, RTAMs displayed strong immunostaining for connexin Cx43. Long chains of interconnected RTAMs arose from perivascular clusters and were dispersed within the tumor parenchyma. When expressed, the glucose transporter Glut1 was found in RTAMs and blood vessels, but rarely in cancer cells.
ATCs display a very dense network of interconnected RTAMs in direct contact with intermingled cancer cells. To our knowledge this is the first time that such a network is described in a malignant tumor. This network was found in all our studied cases and appeared specific to ATC, since it was not found in differentiated thyroid cancers specimens. Taken together, these results suggest that RTAMs network is directly related to the aggressiveness of the disease via metabolic and trophic functions which remain to be determined.
Metastatic pheochromocytomas and paragangliomas (MPPs) present clinicians with three major challenges: scarcity, complexity of characterization, and heterogeneous behavior and prognosis. As with the ...treatment for all neuroendocrine tumors, the control of hormonal symptoms and tumor growth is the main therapeutic objective in MPP patients. A significant number of MPP patients still die from uncontrolled hormone secretion. In addition, the management of MPPs remains palliative. Steps forward include proper characterization of MPP patients at large cancer referral centers with multidisciplinary teams; improved strategies to stratify patients prognostically; and implementation of trials within national and international networks. Progress in the molecular characterization and staging of MPPs constitutes the basis for significant treatment breakthroughs.
Objective: Prophylactic neck dissection for small papillary carcinoma remains controversial. Radioiodine ablation is not recommended for tumors less than 10 mm and depends on various factors for ...tumors between 10 and 20 mm. The aim was to determine the effect of lymph node (LN) staging on the indication for treatment with radioiodine.
Patients and Methods: We conducted a retrospective study of 115 patients presenting with papillary thyroid carcinoma less than 2 cm without ultrasonographically detectable cervical LN treated by total thyroidectomy and complete selective dissection of the central and lateral compartment. Radioiodine treatment was based on definitive pathology (tumor and LN). Follow-up was based on neck ultrasound and thyroglobulin levels.
Results: LN were found for 41.7% of cases. Radioiodine was not used for 42% of patients with tumors less than 20 mm and no metastatic LN. Fifty-eight percent of patients were treated with radioiodine due to LN metastasis, extracapsular thyroid invasion, or unfavorable histological subtype. LN status affected the indication for radioiodine in 30.5% of cases classified as T1, 12 cases with tumors less than 10 mm but with LN metastases (who received radioiodine), and 13 cases with tumors between 10 and 20 mm but without LN metastases (who did not receive radioiodine). Definitive vocal fold paralysis and hypoparathyroidism each occurred in 0.9% of cases. At 1 yr, ultrasound was normal in all patients, and recombinant human TSH-stimulated thyroglobulin was undetectable for 97% of the patients.
Conclusion: Precise LN staging by prophylactic neck dissection for tumors initially staged T1N0 modified the indication for radioiodine ablation for 30% of patients.
Prophylactic lymph node dissection for papillary thyroid carcinoma initially staged T1N0 modified the indication for radioiodine ablation for 30% of patients.
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