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'''Thyroid cancer''' is a [[malignant tumor|malignant]] neoplasm originating from follicular or parafollicular [[thyroid]] cells.
'''Thyroid cancer''' is a [[malignant tumor|malignant]] neoplasm originating from follicular or parafollicular [[thyroid]] cells.


The most effective management of aggressive thyroid cancers is surgical removal of thyroid gland ([[thyroidectomy]]) followed by [[radioactive iodine]] ablation and TSH-suppresion therapy. [[Chemotherapy]] or [[radiotherapy]] may also be used in cases of distant metastases or advanced cancer stage.<ref>http://www.mayoclinic.com/health/thyroid-cancer/DS00492/DSECTION=treatments-and-drugs</ref> Thyroid cancer is very common in older adults and often [[overdiagnosed]]. If it is very slow growing and produces no symptoms, then it requires no treatment.<ref name="WelchSchwartz2011">{{cite book|last1=Welch|first1=H. Gilbert|last2=Schwartz|first2=Lisa|last3=M.D.|first3=Lisa M. Schwartz,|coauthors=Steve Woloshin|title=Overdiagnosed: Making People Sick in the Pursuit of Health|url=http://books.google.com/books?id=qe7XQxzAftEC|accessdate=7 October 2012|date=2011-01-18|publisher=Beacon Press|isbn=9780807022009|pages=138–143}}</ref>
The most effective management of aggressive thyroid cancers is surgical removal of thyroid gland ([[thyroidectomy]]) followed by [[radioactive iodine]] ablation and TSH-suppresion therapy. [[Chemotherapy]] or [[radiotherapy]] may also be used in cases of distant metastases or advanced cancer stage.<ref>http://www.mayoclinic.com/health/thyroid-cancer/DS00492/DSECTION=treatments-and-drugs</ref>.


==Symptoms==
==Symptoms==
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==Treatment==
==Treatment==
Thyroidectomy and dissection of central neck compartment is initial step in treatment of thyroid cancer in majority of cases.<ref name=hu/> Thyroid-preserving operation may be applied in cases, when thyroid cancer exhibits low biological aggressiveness (well-differentiated cancer, no evidence of lymph node metastases, low MIB-1 index, no major genetic alterations (''BRAF'' mutations, ''RET/PTC'' rearrangements, p53 mutations etc) in patients younger then 45 years.<ref name=ATA2009>{{cite journal |url=http://www.ncbi.nlm.nih.gov/pubmed/19860577 |title=Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer.|author=American Thyroid Association (ATA) Guidelines Taskforce on Thyroid Nodules and Differentiated Thyroid Cancer, Cooper DS, Doherty GM, Haugen BR, Kloos RT, Lee SL, Mandel SJ, Mazzaferri EL, McIver B, Pacini F, Schlumberger M, Sherman SI, Steward DL, Tuttle RM. |year=2009 |doi=10.1089/thy.2009.0110 |journal=Thyroid |volume=19 |pages=1167-214 |issue=11 }}</ref>
Some kinds of thyroid cancer are very common in older adults, very slow growing, produce no symptoms, and require no treatment. Treating these patients for a cancer that will not produce any symptoms before their natural death from other causes represents [[overdiagnosis]] and [[overtreatment]] with no benefits to the patient.<ref name="WelchSchwartz2011">{{cite book|last1=Welch|first1=H. Gilbert|last2=Schwartz|first2=Lisa|last3=M.D.|first3=Lisa M. Schwartz,|coauthors=Steve Woloshin|title=Overdiagnosed: Making People Sick in the Pursuit of Health|url=http://books.google.com/books?id=qe7XQxzAftEC|accessdate=7 October 2012|date=2011-01-18|publisher=Beacon Press|isbn=9780807022009|pages=138–143}}</ref>
The wait and watch strategy is not recommended due to high risk of thyroid cancer progression, although a publication suggests such approach in connection to [[overdiagnosis]] and [[overtreatment]] of thyroid cancer among old patients.<ref name="WelchSchwartz2011">{{cite book|last1=Welch|first1=H. Gilbert|last2=Schwartz|first2=Lisa|last3=M.D.|first3=Lisa M. Schwartz,|coauthors=Steve Woloshin|title=Overdiagnosed: Making People Sick in the Pursuit of Health|url=http://books.google.com/books?id=qe7XQxzAftEC|accessdate=7 October 2012|date=2011-01-18|publisher=Beacon Press|isbn=9780807022009|pages=138–143}}</ref>.

Thyroid cancer may require surgery. Common surgeries include [[thyroidectomy]] and [[lobectomy]].<ref name=hu/>

Radioactive [[Iodine-131]] is used in patients with papillary or follicular thyroid cancer for ablation of residual thyroid tissue after surgery and for the treatment of thyroid cancer. Patients with medullary, anaplastic, and most Hurthle cell cancers do not benefit from this therapy.<ref name=hu/>
Radioactive [[Iodine-131]] is used in patients with papillary or follicular thyroid cancer for ablation of residual thyroid tissue after surgery and for the treatment of thyroid cancer. Patients with medullary, anaplastic, and most Hurthle cell cancers do not benefit from this therapy.<ref name=hu/>


Revision as of 13:26, 19 June 2013

Thyroid cancer
SpecialtyOncology Edit this on Wikidata

Thyroid cancer is a malignant neoplasm originating from follicular or parafollicular thyroid cells.

The most effective management of aggressive thyroid cancers is surgical removal of thyroid gland (thyroidectomy) followed by radioactive iodine ablation and TSH-suppresion therapy. Chemotherapy or radiotherapy may also be used in cases of distant metastases or advanced cancer stage.[1].

Symptoms

Micrograph of a lymph node with papillary thyroid carcinoma.

Most often the first symptom of thyroid cancer is a nodule in the thyroid region of the neck.[2] However, many adults have small nodules in their thyroids, but typically under 5% of these nodules are found to be malignant. Sometimes the first sign is an enlarged lymph node. Later symptoms that can be present are pain in the anterior region of the neck and changes in voice due to an involvement of the recurrent laryngeal nerve.

Thyroid cancer is usually found in a euthyroid patient, but symptoms of hyperthyroidism or hypothyroidism may be associated with a large or metastatic well-differentiated tumor.

Thyroid nodules are of particular concern when they are found in those under the age of 20. The presentation of benign nodules at this age is less likely, and thus the potential for malignancy is far greater.

Diagnosis

Further information: Thyroid nodule

After a thyroid nodule is found during a physical examination, a referral to an endocrinologist, or a thyroidologist may occur. Most commonly an ultrasound is performed to confirm the presence of a nodule, and assess the status of the whole gland. Measurement of thyroid stimulating hormone and anti-thyroid antibodies will help decide if there is a functional thyroid disease such as Hashimoto's thyroiditis present, a known cause of a benign nodular goiter.[3] Measurement of calcitonin is necessary to exclude the presence of medullary thyroid cancer. Finally, to achieve a definitive diagnosis before deciding on treatment, a fine needle aspiration cytology test is usually performed.

Classification

Thyroid cancers can be classified according to their histopathological characteristics.[4][5] The following variants can be distinguished (distribution over various subtypes may show regional variation):

The follicular and papillary types together can be classified as "differentiated thyroid cancer".[8] These types have a more favorable prognosis than the medullary and undifferentiated types.[9]

  • Papillary microcarcinoma is a subset of papillary thyroid cancer defined as measuring less than or equal to 1 cm.[10] The highest incidence of papillary thyroid microcarcinoma in autopsy series was reported by Harach et al. in 1985, who found 36 of 101 consecutive autopsies were found to have an incidental microcarcinoma.[11] Michael Pakdaman et al. report the highest incidence in a retrospective surgical series at 49.9% of 860 cases.[12] Management strategies for incidental papillary microcarcinoma on ultrasound (and confirmed on FNAB) range from total thyroidectomy with radioactive iodine ablation to observation alone. Harach et al. suggest using the term "occult papillary tumor" to avoid giving patients distress over having cancer. It was Woolner et al. who first arbitrarily coined the term "occult papillary carcinoma" in 1960, to describe papillary carcinomas ≤ 1.5 cm in diameter.[13]

Etiology

From the 1940s to 1960s, external, low-dose radiation to the head and neck during infancy and childhood was used to treat many benign diseases. This type of therapy has been shown to predispose persons to thyroid cancer. The younger the patient was at time of exposure, the higher the risk of developing cancer.[2]

Another cause may be due to high-dose irradiation to the head and neck. Patients with Hodgkin lymphoma treated with mantlefield irradiation have an increased risk of developing thyroid cancer, although hypothyroidism is more likely.[2]

Detection of metastases

Detection of any metastases of thyroid cancer can be performed with a full body scintigraphy using iodine-131.[14][15]

Treatment

Thyroidectomy and dissection of central neck compartment is initial step in treatment of thyroid cancer in majority of cases.[2] Thyroid-preserving operation may be applied in cases, when thyroid cancer exhibits low biological aggressiveness (well-differentiated cancer, no evidence of lymph node metastases, low MIB-1 index, no major genetic alterations (BRAF mutations, RET/PTC rearrangements, p53 mutations etc) in patients younger then 45 years.[16] The wait and watch strategy is not recommended due to high risk of thyroid cancer progression, although a publication suggests such approach in connection to overdiagnosis and overtreatment of thyroid cancer among old patients.[17]. Radioactive Iodine-131 is used in patients with papillary or follicular thyroid cancer for ablation of residual thyroid tissue after surgery and for the treatment of thyroid cancer. Patients with medullary, anaplastic, and most Hurthle cell cancers do not benefit from this therapy.[2]

External irradiation may be used when the cancer is unresectable, when it recurs after resection, or to relieve pain from bone metastasis.[2]

Sorafenib and sunitinib, approved for other indications show promise for thyroid cancer and are being used for some patients who do not qualify for clinical trials.[18] Numerous agents are in phase II clinical trials and XL184 has started a phase III trial.[18]

Prognosis

The prognosis of thyroid cancer is related to the type of cancer and the stage at the time of diagnosis. For the most common form of thyroid cancer, papillary, the overall prognosis is excellent. Indeed, the increased incidence of papillary thyroid carcinoma in recent years is likely related to increased and earlier diagnosis. One can look at the trend to earlier diagnosis in two ways. The first is that many of these cancers are small and not likely to develop into aggressive malignancies. A second perspective is that earlier diagnosis removes these cancers at a time when they are not likely to have spread beyond the thyroid gland, thereby improving the long-term outcome for the patient. There is no consensus at present on whether this trend toward earlier diagnosis is beneficial or unnecessary.

The argument against early diagnosis and treatment is based on the logic that many small thyroid cancers (mostly papillary) will not grow or metastasize. This viewpoint holds the overwhelming majority of thyroid cancers are overdiagnosed (that is, will never cause any symptoms, illness, or death for the patient, even if nothing is ever done about the cancer). Including these overdiagnosed cases skews the statistics by lumping clinically significant cases in with apparently harmless cancers.[19] Thyroid cancer is incredibly common, with autopsy studies of people dying from other causes showing that more than one third of older adults technically has thyroid cancer, which is causing them no harm.[19] It is easy to detect nodules that might be cancerous, simply by feeling the throat, which contributes to the level of overdiagnosis. However, very few of the people with these accidentally discovered, symptom-free thyroid cancers will ever have any symptoms, and treatment in such patients has only the potential to harm them, not to help them.[19]

Thyroid cancer is three times more common in women than in men, but according to [20] European statistics, the overall relative 5-year survival rate for thyroid cancer is 85% for females and 74% for males.[21]

The table below highlights some of the challenges with decision making and prognostication in thyroid cancer. While there is general agreement that stage I or II papillary, follicular or medullary cancer have a good prognosis, it is not possible when evaluating a small thyroid cancer to determine which ones will grow and metastasize and which will not. As a result once a diagnosis of thyroid cancer has been established (most commonly by a fine needle aspiration), it is likely that a total thyroidectomy will be performed.

This drive to earlier diagnosis has also manifest itself on the European continent by the use of serum calcitonin measurements in patients with goiter to identify patients with early abnormalities of the parafollicular or calcitonin-producing cells within the thyroid gland. As multiple studies have demonstrated, the finding of an elevated serum calcitonin is associated with the finding of a medullary thyroid carcinoma in as high as 20% of cases.

Does the finding of a small medullary thyroid carcinoma (which may lie dormant) justify the performance of a total thyroidectomy (it's necessary to perform total thyroidectomy because the medullary thyroid carcinomas identified may be microscopic and not identified by imaging or evaluation of the thyroid gland at the time of surgery) with its attendant risk of permanent hypoparathyroidism (low calcium) and damage to the nerves innervating the vocal cords (causing permanent hoarseness in 2-4% of patients)?

In Europe where the threshold for thyroid surgery is lower than in the United States, an elaborate strategy that incorporates serum calcitonin measurements and stimulatory tests for calcitonin has been incorporated into the decision to perform a thyroidectomy; thyroid experts in the USA, looking at the same data sets have, for the most part, not incorporated calcitonin testing as a routine part of their evaluation, thereby eliminating a large number of thyroidectomies and the consequent morbidity. The European thyroid community has focused on prevention of metastasis from small medullary thyroid carcinomas; the North American thyroid community has focused more on prevention of complications associated with thyroidectomy (see American Thyroid Association guidelines below). It is not clear at this time who is correct.

As demonstrated in the Table below, individuals with stage III and IV disease have a significant risk of dying from thyroid cancer. While many present with widely metastatic disease, an equal number evolve over years and decades from stage I or II disease. Physicians who manage thyroid cancer of any stage recognize that a small percentage of patients with low-risk thyroid cancer will progress to metastatic disease.

Fortunately for those with metastatic thyroid cancer, the last 5 years has brought about a renaissance in thyroid cancer treatment. The identification of some of the molecular or DNA abnormalities for thyroid cancer has led to the development of therapies that target these molecular defects. The first of these agents to negotiate the approval process is vandetanib, a tyrosine kinase inhibitor that targets the RET proto-oncogene, 2 subtypes of the vascular endothelial growth factor receptor, and the epidermal growth factor receptor.[22] More of these compounds are under investigation and are likely to make it through the approval process. For differentiated thyroid carcinoma, strategies are evolving to use selected types of targeted therapy to increase radioactive iodine uptake in papillary thyroid carcinomas that have lost the ability to concentrate iodide. This strategy would make it possible to use radioactive iodine therapy to treat "resistant" thyroid cancers. Other targeted therapies are being evaluated, making it possible that life will be extended over the next 5–10 years for those with stage III and IV thyroid cancer.

Prognosis is better in younger people than older ones.[21]

Prognosis depends mainly on the type of cancer and cancer stage.

 
Thyroid cancer type		 5-year survival 10-year survival
Stage I Stage II Stage III Stage IV Overall Overall
Papillary 100%[23] 100%[23] 93%[23] 51%[23] 96%[24] or 97%[25] 93%[24]
Follicular 100%[23] 100%[23] 71%[23] 50%[23] 91%[24] 85%[24]
Medullary 100%[23] 98%[23] 81%[23] 28%[23] 80%,[24] 83%[26] or 86%[27] 75%[24]
Anaplastic (always stage IV)[23] 7%[23] 7%[23] or 14%[24] (no data)

See also

References

  1. ^ http://www.mayoclinic.com/health/thyroid-cancer/DS00492/DSECTION=treatments-and-drugs
  2. ^ a b c d e f Hu MI, Vassilopoulou-Sellin R, Lustig R, Lamont JP. "Thyroid and Parathyroid Cancers" in Pazdur R, Wagman LD, Camphausen KA, Hoskins WJ (Eds) Cancer Management: A Multidisciplinary Approach. 11 ed. 2008.
  3. ^ Bennedbaek FN, Perrild H, Hegedüs L (1999). "Diagnosis and treatment of the solitary thyroid nodule. Results of a European survey". Clin. Endocrinol. (Oxf). 50 (3): 357–63. doi:10.1046/j.1365-2265.1999.00663.x. PMID 10435062.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. ^ "Thyroid Cancer Treatment – National Cancer Institute". Retrieved 2007-12-22.
  5. ^ "Thyroid cancer". Retrieved 2007-12-22.
  6. ^ a b c d Chapter 20 in: Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson. Robbins Basic Pathology. Philadelphia: Saunders. ISBN 1-4160-2973-7.{{cite book}}: CS1 maint: multiple names: authors list (link) 8th edition.
  7. ^ Schlumberger M, Carlomagno F, Baudin E, Bidart JM, Santoro M (2008). "New therapeutic approaches to treat medullary thyroid carcinoma". Nat Clin Pract Endocrinol Metab. 4 (1): 22–32. doi:10.1038/ncpendmet0717. PMID 18084343.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. ^ Nix P, Nicolaides A, Coatesworth AP (2005). "Thyroid cancer review 2: management of differentiated thyroid cancers". Int. J. Clin. Pract. 59 (12): 1459–63. doi:10.1111/j.1368-5031.2005.00672.x. PMID 16351679.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ^ Nix PA, Nicolaides A, Coatesworth AP (2006). "Thyroid cancer review 3: management of medullary and undifferentiated thyroid cancer". Int. J. Clin. Pract. 60 (1): 80–4. doi:10.1111/j.1742-1241.2005.00673.x. PMID 16409432.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  10. ^ Shaha AR (2007). "TNM classification of thyroid carcinoma". World J Surg. 31 (5): 879–87. doi:10.1007/s00268-006-0864-0. PMID 17308849.
  11. ^ Harach HR, Franssila KO, Wasenius VM (1985). "Occult papillary carcinoma of the thyroid. A "normal" finding in Finland. A systematic autopsy study". Cancer. 56 (3): 531–8. doi:10.1002/1097-0142(19850801)56:3<531::AID-CNCR2820560321>3.0.CO;2-3. PMID 2408737.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  12. ^ Pakdaman MN, Rochon L, Gologan O, Tamilia M, Garfield N, Hier MP, Black MJ, Payne RJ (2008). "Incidence and histopathological behavior of papillary microcarcinomas: Study of 429 cases". Otolaryngol Head Neck Surg. 139 (5): 718–22. doi:10.1016/j.otohns.2008.08.014. PMID 18984270.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  13. ^ LEWIS B. WOOLNER, M.D., MARK L. LEMMON, M.D.{dagger}, OLIVER H. BEAHRS, M.D., B. MARDEN BLACK, M.D. and F. RAYMOND KEATING, JR., M.D. OCCULT PAPILLARY CARCINOMA OF THE THYROID GLAND: A STUDY OF 140 CASES OBSERVED IN A 30-YEAR PERIOD* Journal of Clinical Endocrinology & Metabolism Vol. 20, No. 1 89–105 doi:10.1210/jcem-20-1-89 PMID 13845950 [PubMed – OLDMEDLINE]
  14. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1677/ERC-07-0120, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1677/ERC-07-0120 instead. [1]
  15. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 3183748, please use {{cite journal}} with |pmid=3183748 instead. [2]
  16. ^ American Thyroid Association (ATA) Guidelines Taskforce on Thyroid Nodules and Differentiated Thyroid Cancer, Cooper DS, Doherty GM, Haugen BR, Kloos RT, Lee SL, Mandel SJ, Mazzaferri EL, McIver B, Pacini F, Schlumberger M, Sherman SI, Steward DL, Tuttle RM. (2009). "Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer". Thyroid. 19 (11): 1167–214. doi:10.1089/thy.2009.0110.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  17. ^ Welch, H. Gilbert; Schwartz, Lisa; M.D., Lisa M. Schwartz, (2011-01-18). Overdiagnosed: Making People Sick in the Pursuit of Health. Beacon Press. pp. 138–143. ISBN 9780807022009. Retrieved 7 October 2012. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)CS1 maint: extra punctuation (link) CS1 maint: multiple names: authors list (link)
  18. ^ a b Sherman (2009). "Advances in Chemotherapy of Differentiated Epithelial and Medullary Thyroid Cancers". Journal of Clinical Endocrinology & Metabolism. 94 (5): 1493–1499. doi:10.1210/jc.2008-0923.
  19. ^ a b c Welch, H. Gilbert (2011). Overdiagnosed: Making People Sick in the Pursuit of Health. [Malaysia?]: Beacon Press. pp. 61–34. ISBN 0-8070-2200-4. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  20. ^ "Thyroid Cancer". MedicineNet.com. Retrieved 26 October 2011.
  21. ^ a b Numbers from EUROCARE, from Page 10 in: F. Grünwald; Biersack, H. J.; Grںunwald, F. (2005). Thyroid cancer. Berlin: Springer. ISBN 3-540-22309-6.{{cite book}}: CS1 maint: multiple names: authors list (link)
  22. ^ "FDA approves new treatment for rare form of thyroid cancer". Retrieved 7 April 2011.
  23. ^ a b c d e f g h i j k l m n o cancer.org > Thyroid Cancer By the American Cancer Society. In turn citing: AJCC Cancer Staging Manual (7th ed).
  24. ^ a b c d e f g Numbers from National Cancer Database in the US, from Page 10 in: F. Grünwald; Biersack, H. J.; Grںunwald, F. (2005). Thyroid cancer. Berlin: Springer. ISBN 3-540-22309-6.{{cite book}}: CS1 maint: multiple names: authors list (link) (Note:Book also states that the 14% 10-year survival for anaplastic thyroid cancer was overestimated
  25. ^ Rounded up to nearest natural number from 96.7% as given by eMedicine > Thyroid, Papillary Carcinoma Author: Luigi Santacroce. Coauthors: Silvia Gagliardi and Andrew Scott Kennedy. Updated: Sep 28, 2010
  26. ^ By 100% minus cause-specific mortality of 17% at 5 yr, as given by [3] Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1210/jc.2005-0044, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1210/jc.2005-0044 instead.
  27. ^ National Cancer Institute > Medullary Thyroid Cancer Last Modified: 12/22/2010

External links

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