Merkel cell cancer

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. Merkel cell carcinoma is the most serious form of skin 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. Recurrence can occur in up to half of all patients. ^[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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Epidemiology

This type of cancer occurs mostly in — though 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. ^[2] Merkel cell cancer can be mistaken for another cancer like basal cell carcinoma, squamous cell carcinoma, malignant melanoma, lymphoma, 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.

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 spread. It is difficult to cure once it has spread.

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.

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.

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. ^[3]

Famous people who have had Merkel cell cancer

• David Brudnoy Boston talk radio host
• Max Perutz Nobel-prize winning chemist
• Joe Zawinul Jazz musician
• Lindsay Thompson Former Premier of Victoria, Australia

See also

• Cancer
• Carcinogenesis

References

1. ^ Allen PJ, Browne WB, Jaques DP, et al. (2005). "Merkel cell carcinoma: Prognosis and treatment of patients from a single institution.". Journal of Clinical Oncology 23 (10): 2300-2309.
2. ^ Hodgson NC. (2005). "Merkel cell carcinoma: Changing incidence trends.". Journal of surgical oncology 89 (1): 1-4.
3. ^ Sentinel Lymph Node Biopsy for Evaluation and Treatment of Patients With Merkel Cell Carcinoma The Dana-Farber Experience and Meta-analysis of the Literature Sheela G. Gupta, MD; Linda C. Wang, MD, JD; Pablo F. Peñas, MD, PhD; Martina Gellenthin, MD; Stephanie J. Lee, MD, MPH; Paul Nghiem, MD, PhD Arch Dermatol. 2006;142:685-690.

• Merkel Cell Cancer Discussion Group
• www.merkelcell.org--Information for Patients & Their Physicians From the Seattle Cancer Care Alliance
• National Cancer Institute listing for Merkel cell cancer
• In-depth medical article on EMedicine
• Información general sobre el carcinoma de células de Merkel - Information About Merkel Cell Cancer in Spanish