Merkel cell cancer
From Wikipedia, the free encyclopedia
| Merkel cell cancer Classification and external resources |
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| ICD-10 | C44. (M8247/3) |
|---|---|
| DiseasesDB | 31386 |
| eMedicine | DERM/262 ent/714 |
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This article or section is missing citations or needs footnotes. Using inline citations helps guard against copyright violations and factual inaccuracies. (September 2007) |
Merkel cell cancer, also called Merkel cell carcinoma, trabecular cancer, Apudoma of skin, or Small cell neuroepithelial tumor of the skin, is a rare and highly aggressive cancer where malignant cancer cells develop on or just beneath the skin and in hair follicles. This cancer is a type of neuroendocrine tumor, like small cell lung cancer. Once it has metastasized to the lymph nodes, the 5-year survival rate for a patient is about 50 percent. A small tumor (less than 2 cm) that has not metastasized to the lymph nodes reported a 5-year survival rate of more than 90 percent; however, at the time of diagnosis of MCC the 5-year survival was 64 percent. Up to half of patients suffer a recurrence.[1]
It occurs most often on the face, head, and neck. It usually appears as firm, painless, nodules, or tumors. These flesh-colored, red, or blue tumors vary in size from 5 mm (less than a quarter of an inch) to more than 5cm (2 inches). The tumor grows rapidly. About half of all Merkel cell cancers occur on the sun-exposed areas of the head and neck, while one-third begin on the legs, and 15% occur on the arms. The cancer may also begin on other parts of the body, such as the trunk.
From initial onset, Merkel cell cancer metastasizes quickly and spreads to other parts of the body, tending towards the regional lymph nodes. The tumor tends to invade underlying subcutaneous fat, fascia, and muscle. It can also metastasize to the liver, lungs, brain or bones.
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[edit] Cause
A newly discovered virus called Merkel cell polyomavirus (MCV) is suspected to contribute to the development of the majority of MCC. Approximately, 80% of MCC tumors have this virus integrated in a monoclonal pattern [1][2], indicating that the infection was present in a precursor cell before it became cancerous. Polyomaviruses have been known to be cancer viruses in animals since the 1950s [3], but this is the first polyomavirus strongly suspected to cause tumors in humans. Like other tumor viruses, most people who are infected with MCV probably do not develop MCC; it is unknown what other steps are required for the development of MCC.[2] Ultraviolet light (sun) exposure probably contributes to MCC development in a large number of cases. MCC also occurs more frequently than expected among immunosuppressed patients, such as transplant patients, AIDS patients and elderly persons, indicating that the tumor is under immune control[4]. At least 20% of MCC tumors are not infected with MCV suggesting that MCC may have multiple causes.
[edit] Epidemiology
This type of cancer occurs mostly in — though is not restricted to — Caucasians between 60 and 80 years of age. It occurs about twice as often in males as in females. There are roughly 1200 new cases diagnosed a year in the United States, compared to 60,000 new cases of melanoma and over 1 million new cases of nonmelanoma skin cancer.[3] Merkel cell cancer can be mistaken for another cancer like basal cell carcinoma, squamous cell carcinoma, malignant melanoma, lymphoma, or small cell carcinoma, or may appear to be a benign cyst. Researchers believe that exposure to sunlight or ultraviolet light may increase a person’s risk of this disease.
Immune suppression can profoundly increase one's risk of developing Merkel cell cancer. According to a recent study in the Lancet, Merkel cell carcinoma occurs 13.4 times more often in people with advanced HIV as compared to the general population. Solid organ transplant recipients have similarly increased risk.
[edit] Treatment
Because Merkel cell cancer is uncommon and is difficult to diagnose, patients may want a second opinion about the diagnosis and treatment plan before starting treatment. However, early diagnosis and treatment of Merkel cell cancer are important factors in decreasing the chance of its spreading, after which it is difficult to cure.
[edit] Surgery
Surgery is the usual treatment for Merkel cell cancer. The tumor is removed along with a border of healthy tissue surrounding it. Nearby, or regional, lymph nodes are often removed because they may contain cancer cells. Sometimes the doctor performs a sentinel lymph node biopsy. In this procedure, the doctor injects a dye or radioactive substance near the tumor. This material flows into the first lymph nodes where cancer is likely to spread (the sentinel nodes). These nodes are then removed and checked for cancer cells. This procedure has been demonstrated to be an important prognostic indicator. Results help dictate the use of appropriate adjuvant therapy, if necessary.
[edit] Radiation and chemotherapy
Adjuvant radiotherapy has been shown to be effective in reducing recurrence and increasing five year survival of patients with Merkel Cell Carcinoma. Patients who present with no metastases and a negative sentinel lymph node biopsy have a good prognosis when treated with surgery and radiotherapy - approximately 90% survival at five years.
Merkel cell cancer that has metastasized may respond to treatment with chemotherapy and/or radiation. This therapy usually does not cure the disease, but can be effective in shrinking the tumor if the tumor is too large to be removed, or is located in a place where removal would be difficult or dangerous.
[edit] Sentinel lymph node biopsy
Sentinel lymph node biopsy detects MCC spread in one third of patients whose tumors would have otherwise been clinically and radiologically understaged and who may not have received treatment to the involved node bed. There was a significant benefit of adjuvant nodal therapy, but only when the SLNB was positive. Thus, SLNB is important for both prognosis and therapy and should be performed routinely for patients with MCC. In contrast, computed tomographic scans have poor sensitivity in detecting nodal disease as well as poor specificity in detecting distant disease.[4]
[edit] Famous people who have had Merkel cell cancer
- David Brudnoy Boston talk radio host
- Max Perutz Nobel-prize winning chemist
- Lindsay Thompson Former Premier of Victoria, Australia
- Joe Zawinul Jazz musician
[edit] See also
[edit] References
- ^ Allen PJ, Bowne WB, Jaques DP, Brennan MF, Busam K, Coit DG (2005). "Merkel cell carcinoma: prognosis and treatment of patients from a single institution". J. Clin. Oncol. 23 (10): 2300–9. doi:. PMID 15800320.
- ^ New virus linked to rare but lethal skin cancer. Retrieved on 2008-02-26.
- ^ Hodgson NC (2005). "Merkel cell carcinoma: changing incidence trends". J Surg Oncol 89 (1): 1–4. doi:. PMID 15611998.
- ^ Gupta SG, Wang LC, Peñas PF, Gellenthin M, Lee SJ, Nghiem P (2006). "Sentinel lymph node biopsy for evaluation and treatment of patients with Merkel cell carcinoma: The Dana-Farber experience and meta-analysis of the literature". Arch Dermatol 142 (6): 685–90. doi:. PMID 16785370.
[edit] External links
- Merkel Cell Cancer Discussion Group
- Merkel cell carcinoma--Information for Patients & Their Physiciansis. Seattle Cancer Care Alliance (03/25/08). Retrieved on 2008-04-13.
- National Cancer Institute (01/02/2007). Merkel Cell Carcinoma: Questions and Answers. National Institutes of Health (US). Retrieved on 2008-04-13.
