Anaplastic thyroid cancer

Anaplastic thyroid cancer (ATC) (or undifferentiated) is a form of thyroid cancer which has a very poor prognosis (14% ten-year survival ratecite journal |author=Hundahl SA, Fleming ID, Fremgen AM, Menck HR |title=A National Cancer Data Base report on 53,856 cases of thyroid carcinoma treated in the U.S., 1985-1995 [see commetns] |journal=Cancer |volume=83 |issue=12 |pages=2638–48 |year=1998 |pmid=9874472|doi=10.1002/(SICI)1097-0142(19981215)83:12<2638::AID-CNCR31>3.0.CO;2-1 |doilabel=10.1002/(SICI)1097-0142(19981215)83:122638::AID-CNCR313.0.CO;2-1] ) due to its aggressive behavior and resistance to cancer treatments.cite journal |author=Liu AH, Juan LY, Yang AH, Chen HS, Lin HD |title=Anaplastic thyroid cancer with uncommon long-term survival |journal=J Chin Med Assoc |volume=69 |issue=10 |pages=489–91 |year=2006 |pmid=17098674 |doi= |url=http://health.elsevier.com/ajws_pubmed/pubmed_switch.asp?journal_issn=1726-4901&art_pub_year=2006&%20art_pub_month=10&art_pub_vol=69&art_sp=489]

Presentation

It rapidly invades surrounding tissues (such as the trachea). The presence of regional lymphadenopathy in older patients in whom FNA reveals characteristic vesicular appearance of the nuclei would support a diagnosis of anaplastic carcinoma.

Treatment

Unlike its differentiated counterparts, anaplastic thyroid cancer is highly unlikely to be curable either by surgery or by any other treatment modality, and is in fact usually unresectable due to its high propensity for invading surrounding tissues. cite journal |author=Haigh PI |title=Anaplastic thyroid carcinoma |journal=Curr Treat Options Oncol |volume=1 |issue=4 |pages=353–7 |year=2000 |pmid=12057160 |doi=]

Palliative treatment consists of radiation therapy usually combined with chemotherapy.

However, with today's technology, new drugs, such as combretastatin (fosbretabulin) Bortezomib and TNF-Related Apoptosis Induced Ligand (TRAIL), are being introduced and trialed in clinical labs and human clinical studies. Based on encouraging Phase I and II clinical trial results, with combretastatin (fosbretabulin), a type of drug that selectively destroys tumor blood-vessels, a large, multi-national clinical trial is being undertaken to determine whether the drug can extend the survival of patients with ATC. (For further information see www.thyca.org) Recent studies in Italy, have shown positive results against ATC, but more tests, outside the lab, are needed to confirm this, before it can be used in Chemotherapy. There have been some case studies where patients with aggressive Thyroid Cancer have survived outside the mean expected survival time. But the best treatment recommended at this stage is early detection and complete surgery, followed by Chemotherapy alongside Radiotherapy, for any chance of survival of ATC.

Post-operative radiotherapy

The role of external beam radiotherapy (EBRT) in thyroid cancer remains controversial and there is no level I evidence to recommend it. No published randomised controlled trials have examined the addition of EBRT to standard treatment, namely surgery, radioactive iodine and medical suppression of thyroid stimulating hormones.cite journal |author=Ford D, Giridharan S, McConkey C, "et al" |title=External beam radiotherapy in the management of differentiated thyroid cancer |journal=Clin Oncol (R Coll Radiol) |volume=15 |issue=6 |pages=337–41 |year=2003 |pmid=14524487 |doi=]

Imbalances in age, sex, completeness of surgical excision, histological type and stage, between patients receiving and not receiving EBRT, confound retrospective studies. Variability also exists between treatment and non-treatment groups in the use of radio-iodine and post-treatment thyroid stimulating hormone (TSH) suppression and treatment techniques between and within retrospective studies.

Some recent studies have indicated that EBRT may be promising, though the number of patients studies has been small.cite journal |author=Meadows KM, Amdur RJ, Morris CG, Villaret DB, Mazzaferri EL, Mendenhall WM |title=External beam radiotherapy for differentiated thyroid cancer |journal=Am J Otolaryngol |volume=27 |issue=1 |pages=24–8 |year=2006 |pmid=16360819 |doi=10.1016/j.amjoto.2005.05.017 |url=http://linkinghub.elsevier.com/retrieve/pii/S0196-0709(05)00113-4]

Clinical trials for investigational treatments are often considered by healthcare professionals and patients as first-line treatment.

Adjuvant therapy

Treatment of anaplastic-type carcinoma is generally palliative in its intent for a disease that is rarely cured and almost always fatal. The median survival from diagnosis ranges from 3 to 7 months, with worse prognosis associated with large tumours, distant metastases, acute obstructive symptoms, and leucocytosis. Death is attributable to upper airway obstruction and suffocation in half of patients, and to a combination of complications of local and distant disease, or therapy, or both in the remainder. In the absence of extracervical or unresectable disease, surgical excision should be followed by adjuvant radiotherapy. In the 18–24% of patients whose tumour seems both confined to the neck and grossly resectable, complete surgical resection followed by adjuvant radiotherapy and chemotherapy could yield a 75–80% survival at 2 years.

There are a number of clinical trials for anaplastic thyroid carcinoma underway or being planned.cite web |url=http://www.thyroidtrials.org |title=American Thyroid Association - Thyroid Clinical Trials |accessdate=2007-12-21 |format= |work=]

Prognosis

Anaplastic thyroid cancer is extremely aggressive, in most cases death occurs in less than 1 year as a result of aggressive local growth and compromise of vital structures in the neck. ATC in most series has a median survival of 4 to 5 months from the time of diagnosis, with rare long-term survivors. [Kumar V, Abbas AK, Fausto N, and Mitchel RN, "Robbins basic Pathology", Saunders, 8th ed., 2007.]

References