Thyroid cancer is a cancer that develops from the tissues of the thyroid gland. It is a disease in which cells grow abnormally and have the potential to spread to other parts of the body. Symptoms can be swelling or lumps in the neck. Cancer may also occur in the thyroid after spreading from other sites, in which case it is not classified as thyroid cancer.
Risk factors include exposure to radiation at a young age, having an enlarged thyroid, and a family history. There are four main types - papillary thyroid cancer, follicular thyroid cancer, medullary thyroid cancer, and anaplastic thyroid cancer. Diagnosis is often based on the aspiration of the ultrasound and fine needle. Screening of people without symptoms and at normal risk for this disease is not recommended by 2017.
Treatment options may include surgery, radiation therapy including radioactive iodine, chemotherapy, thyroid hormone, targeted therapy, and waiting with caution. Surgery may involve partial or complete removal of the thyroid. The five-year survival rate is 98% in the United States.
Globally by 2015 3.2 million people have thyroid cancer. In 2012, 298,000 new cases occur. Most commonly between the ages of 35 and 65. Women are more often affected than men. Asian-Americans are more frequently affected. Prices have risen in recent decades believed to be due to better detection. By 2015 it generates 31,900 deaths.
Video Thyroid cancer
Signs and symptoms
Most often the first symptoms of thyroid cancer are nodules in the thyroid region of the neck. However, up to 65% of adults have small nodules in their thyroid, but usually under 10% of these nodules are found to be cancerous. Sometimes the first sign is an enlarged lymph node. The later symptoms that can be present are pain in the anterior region of the neck and sound changes due to recurrent laryngeal nerve involvement.
Thyroid cancer is usually found in eutyroid patients, but symptoms of hyperthyroidism or hypothyroidism may be associated with a well-differentiated large or metastatic tumor.
Thyroid nodules are of particular concern when found in those under the age of 20. Presentation of benign nodules at this age is less likely, and thus the potency of malignancy is much greater.
Maps Thyroid cancer
Cause
Thyroid cancer is thought to be associated with a number of environmental and genetic predisposing factors, but significant uncertainty remains about the cause.
Environmental exposure to ionizing radiation from both natural and artificial source sources allegedly plays an important role, and there is a significant increase of thyroid cancer in those exposed to mantlefield radiation for lymphoma, and those exposed to iodine-131 follow Chernobyl, Fukushima nuclear disaster, Kyshtym, and Windscale. Thyroiditis and other thyroid diseases also predispose to thyroid cancer.
Genetic causes include some type 2 endocrine neoplasia that significantly increase levels, especially from the more rare medullic form of the disease.
Diagnosis
After a thyroid nodule is found during a physical exam, referral to an endocrinologist or thyroid expert may occur. Most common ultrasound is performed to confirm the presence of nodules and assess the status of the entire gland. Measurement of thyroid stimulating hormone and anti-thyroid antibodies will help decide whether there is a functional thyroid disease such as Hashimoto's thyroiditis, known to be a benign nodular goiter. Calcitonin measurement is needed to rule out 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 and reported in accordance with the Bethesda system.
In adults without symptom screening for thyroid cancer is not recommended.
Classification
Thyroid cancer can be classified according to their histopathological characteristics. The following variations can be distinguished (distribution through multiple subtypes can indicate regional variation):
- Papillary thyroid cancer (75% to 85% of cases) - often in young women - an excellent prognosis. May occur in women with familial adenomatous polyposis and in patients with Cowden syndrome.
- Reclassified new variants: noninvasive follicular thyroid neoplasms with papillary-like nuclear features are considered as indolent tumors of limited biological potential.
- Follicular thyroid cancer (10% to 20% of cases) - is sometimes seen in people with Cowden syndrome. Some include HÃÆ'¼rthle cell carcinoma as a variant and others note it as a separate type.
- Medullary thyroid cancer (5% to 8% of cases) - paraffolic cell cancer, often a part of multiple endocrine neoplasia of type 2.
- Thyroid cancer with poor differentiation
- Anaplastic thyroid cancer (less than 5% of cases) is unresponsive to treatment and may cause pressure symptoms.
- More
- Thyroid lymphoma
- Squamous cell carcinoma
- Thyroid sarcoma
Follicular and papillary forms together can be classified as "differentiated thyroid cancer". These types have a more favorable prognosis than the medullary and undifferentiated types.
- papillary microcarcinoma is part of papillary thyroid cancer defined as being less than or equal to 1 cm. The highest incidence of papillary thyroid microcarcinoma in autopsy series was reported by Harach et al. in 1985, who found 36 of 101 autopsies in succession were found to have incidental microcarcinoma. Michael Pakdaman et al. reported the highest incidence in a series of retrospective surgeries in 49.9% of 860 cases. Management strategies for incidental papillary microcarcinoma in ultrasound (and confirmed in FNAB) range from total thyroidectomy with radioactive iodine ablation for observation only. Harach et al. suggest using the term "paprika occult tumor" to avoid patients suffering from cancer. That's Woolner et al. who first arbitrarily coined the term "occult papillary carcinoma" in 1960, to describe papillary carcinoma <= 1.5 cm in diameter.
Staging
The stage of cancer is the process of determining the extent of cancer development. TNM staging systems are commonly used to classify the stage of cancer but not the brain.
Metastasis
Detection of any thyroid cancer metastasis can be done by skintigrafi throughout the body using iodine-131.
Spread
Thyroid cancer can spread directly, through the lymphatic or through the blood. Direct spread occurs through infiltration of surrounding tissue. Infiltyo tumor becomes the muscles of infrahyoid, trachea, esophagus, recurrent laryngeal nerves, carotid sheath, etc. The tumor then becomes fixed. Anaplastic carcinoma spreads largely by direct spread, whereas papillary carcinoma spreads least. Lymphatic spread is most common in papillary carcinoma. The cervical lymph nodes become palpable in papillary carcinomas even when the primary tumor can not be resolved. Deep cervical nodes, pretracheal, prelaryngeal and paratracheal lymph nodes are often affected. The affected lymph nodes are usually the same side as the location of the tumor. Blood distribution is also possible in thyroid cancer, especially in follicular and anaplastic carcinomas. Embolic tumors do angioinvasion and lung, long bony end, skull and spine are affected. Metastatic pulsation occurs due to their increased vascularization.
Treatment
Thyroidectomy and dissection of the central neck compartment is the first step in the treatment of thyroid cancer in most cases. Thyroid cycling surgery can be applied in cases, when thyroid cancer exhibits low biological aggressiveness (eg i well-differentiated cancer, no evidence of lymph node metastasis, low MIB-1 index, no change genetic major such as BRAF mutation, RET/PTC reordering, p53 mutation, etc.) in patients younger than 45 years. If the diagnosis of well-differentiated thyroid cancer (eg papillary thyroid cancer) is established or suspected by FNA, surgery is indicated, while a vigilant waiting strategy is not recommended in evidence-based guidelines. Vigilant waiting reduced the overdiagnosis and overtreatment of thyroid cancer among the old patients.
Radioactive Iodine-131 is used in patients with papillary or follicular thyroid cancer for residual thyroid ablation after surgery and for treatment of thyroid cancer. Patients with medullary, anaplastic, and most Lung cancer cells did not benefit from this therapy.
External irradiation can be used when cancer is inoperable, when repeated after resection, or to relieve pain from bone metastases.
Sorafenib and lenvatinib, approved for advanced metastatic thyroid cancer. Many agents are in Phase II and III clinical trials.
Prognosis
The prognosis of thyroid cancer is associated with the type of cancer and stage at the time of diagnosis. For the most common form of thyroid cancer, papillary, the overall prognosis is excellent. Indeed, an increase in the incidence of papillary thyroid carcinoma in recent years may be linked to earlier increases and diagnoses. One can see a tendency for early diagnosis in two ways. The first is that many of these cancers are small and may not develop into aggressive malignancies. A second perspective is that earlier diagnoses eliminate these cancers when they may not have spread beyond the thyroid gland, thus increasing long-term outcomes for patients. There is no current consensus on whether this earlier trend toward diagnosis is beneficial or unnecessary.
Arguments that challenge diagnosis and early treatment are based on the logic that many small thyroid cancers (mostly papillary) will not grow or metastasize. This viewpoint holds most of the undiagnosed thyroid cancer (ie, will never cause symptoms, illness, or death to the patient, even if nothing has ever been done about cancer). Including cases that are too undiagnosed to make statistics become less sharp by lining up significant clinical cases with seemingly innocuous cancers. Thyroid cancer is very common, with autopsy studies of people who died from other causes indicating that more than one-third of older adults technically have thyroid cancer, which causes them no harm. It is very easy to detect cancerous nodules, only by feeling the throat, which contributes to the degree of overdiagnosis. Benign nodules (non-cancerous) are often adjacent to thyroid cancer; Sometimes, it is a benign nodule that is found but the operation reveals a small incidental thyroid cancer. More small thyroid nodules are found as incidental findings on imaging (CT scan, MRI, ultrasound) performed for other purposes; very few of these people have accidentally discovered that asymptomatic thyroid cancer will ever have any symptoms, and treatment of such patients has the potential to cause harm to them, not to help them.
Thyroid cancer is three times more common in women than in men, but according to European statistics, the overall 5 year relative survival rate for thyroid cancer is 85% for women and 74% for men.
The table below highlights some of the challenges with decision making and prognostication on thyroid cancer. Although there is general agreement that stage I or II papillary, follicular or medullary cancer has a good prognosis, it is impossible when evaluating small thyroid cancer to determine which will grow and metastasize and which are not. As a result, after the diagnosis of thyroid cancer has been established (most commonly by fine needle aspiration), it is likely that total thyroidectomy will be performed.
This impetus for earlier diagnoses has also manifested itself in the European continent by using measurement of serum calcitonin in patients with goitre to identify patients with early paraffollicular or calcitonin cell abnormalities in the thyroid gland. As some studies have shown, the increased serum calcitonin findings are associated with medullary thyroid carcinoma findings in as high as 20% of cases.
In Europe where the threshold for thyroid surgery is lower than in the United States, a complicated strategy that combines the measurement of serum calcitonin and the stimulation test for calcitonin has been incorporated into the decision to perform thyroidectomy; thyroid experts in the United States, saw the same data set, for the most part, excluding calcitonin testing as a routine part of their evaluation, thus eliminating a large number of thyroidectomy and consequent morbidity. The European thyroid community focuses on the prevention of metastases from small medullary thyroid carcinomas; North American thyroid communities focus more on prevention of complications associated with thyroidectomy (see American Thyroid Association guidelines below). It is not clear at the moment who is right.
As shown in the Table below, individuals with stage III and IV disease have a significant risk of death from thyroid cancer. While many present with extensive metastatic disease, the same number evolved over the years and decades of stage I or II disease. Doctors who treat thyroid cancer at any stage recognize that a small percentage of patients with low-risk thyroid cancer will develop into a metastatic disease.
Fortunately for those with metastatic thyroid cancer, the last 5 years have brought a revival in the treatment of thyroid cancer. Identification of some molecular or DNA disorders 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 were vandetanib, a tyrosine kinase inhibitor targeting RET proto-oncogene, 2 subtypes of vascular endothelial growth factor receptor, and epidermal growth factor receptor. More of these compounds are being investigated and likely to make it through the approval process. For differentiated thyroid carcinomas, strategies evolve to use certain types of target therapy to improve radioactive iodine absorption in papillary thyroid carcinoma that has lost the ability to concentrate iodide. This strategy will make it possible to use radioactive iodine therapy to treat "resistant" thyroid cancer. Other targeted therapies are being evaluated, allowing life to be extended for another 5-10 years for those with stage III and IV thyroid cancers.
Prognosis is better at younger people than older ones.
The prognosis mainly depends on the type of cancer and the stage of the cancer.
Epidemiology
Thyroid cancer, in 2010, produced 36,000 deaths globally up from 24,000 in 1990. Obesity may be associated with a higher incidence of thyroid cancer, but this relationship remains a matter of debate.
Thyroid cancer accounts for less than 1% of cancer cases and deaths in the UK. About 2,700 people were diagnosed with thyroid cancer in the UK in 2011, and about 370 people died of disease in 2012.
Famous cases
- Daniel Snyder, American owner of the Washington Redskins football team
- Jerry Dipoto, a former Premier League Baseball pitcher
- William Rehnquist, US Justice Chief (1986-2005) died on 3 September 2005 from anaplastic thyroid cancer
References
External links
- Thyroid cancer in Curlie (based on DMOZ)
- Cancer Management Handbook: Thyroid and Parathyroid Cancer
- Management Guidelines for Patients with Thyroid Nodules and Thyroid Cancer Differentiation of the American Thyroid Association Task Force (2015).
- Statistics of thyroid cancer from Cancer Research UK
Source of the article : Wikipedia
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