Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer.[1] It is commonly diagnosed in men, people over the age of 50 and those with a history of other cancers and/or those with fair skin.[1-3] Every year, approximately 2,500 new cases of MCC are diagnosed in both the United States and in Europe.[4,5]

When the cancer begins to spread to other areas of the body, it becomes metastatic MCC, a hard-to-treat cancer.[1] Overall, 5–12% of patients with MCC are affected with metastatic MCC and have a particularly poor prognosis.[4, 6-9]

Only 30–64% of patients with MCC of any stage survive beyond 5 years; for patients with metastatic MCC, this survival rate is lower than 20%.[9,10]

This often misdiagnosed type of skin cancer occurs in the top layer of the skin, near nerve endings that sense touch.[1] MCC appears as painless pink, red or purple bumps on the skin. These bumps are usually on areas of the skin that receive sun exposure, such as the face, neck, arms and legs, though they can appear anywhere on the body.[11,12]

As with other cancers, treatment of MCC depends on the stage of the disease, as well as the age and health of the patient.[11] Although doctors only have a handful of options to treat this challenging cancer, progress is being made in discovering new ways of treating this rare disease.[13]

References:

1. National Cancer Institute. Merkel Cell Carcinoma Treatment–Patient Version (PDQ®). Available from: https://www.cancer.gov/types/skin/patient/merkel-cell-treatment-pdq. Accessed June 2017.
2. American Cancer Society. Merkel Cell Carcinoma Risk Factors. Available from: http://www.cancer.org/cancer/skincancer-merkelcell/detailedguide/skin-cancer-merkel-cell-carcinoma-risk-factors.  Accessed August 2017.
3. Skin Cancer Foundation. Merkel Cell Carcinoma: An Uncommon but Often Lethal Skin Cancer. Available from: http://www.skincancer.org/skin-cancer-information/merkel/risk.  Accessed August 2017.
4. Fitzgerald TL, et al. Dramatic Increase in the Incidence and Mortality from Merkel Cell Carcinoma in the United States. The American Journal of Surgery. 2015;81(8):802-6.
5. IMMOMEC (European Commission). Merkel Cell Carcinoma. Available from: http://www.immomec.eu/project/objectives/background/merkel-cell-carcinoma. Accessed June 2017.
6. Heath M, et al. Clinical Characteristics of Merkel Cell Carcinoma at Diagnosis in 195 Patients: The AEIOU features. Journal of the American Academy of Dermatology. 2008;58(3):375–81.
7. Stokes JB, et al. Patients with Merkel Cell Carcinoma Tumors < or = 1.0 cm in Diameter are Unlikely to Harbor Regional Lymph Node Metastasis. Journal of Clinical Oncology. 2009;27(23):3772–3777.
8. Allen PJ, et al. Merkel Cell Carcinoma: Prognosis and Treatment of Patients From a Single Institution. Journal of Clinical Oncology 2005;23(10):2300–2309.
9. Lemos B et al. Pathologic Nodal Evaluation Improved Prognostic Accuracy in Merkel Cell Carcinoma: Analysis of 5,823 Cases as the Basis of the First Consensus Staging System for this Cancer. Journal of the American Academy of Dermatology 2010;63:751–761.
10. NCCN Merkel Cell Carcinoma Guidelines Version I. 2017. Available from: www.nccn.org/professionals/physician_gls/PDF/mcc.pdf. Accessed August 2017.
11. American Cancer Society. Treating Merkel Cell Carcinoma Based on the Extent of the Cancer. Available from: https://www.cancer.org/cancer/merkel-cell-skin-cancer/treating/common-treatments-by-extent.html. Accessed August 2017.
12. Duprat J, Landman G, Salvajoli J and Brechtbühl E. A Review of the Epidemiology and Treatment of Merkel Cell Carcinoma. Clinics. 2011;66(10):1817–1823.
13. Swann MH & Yoon J. Merkel Cell Carcinoma. Seminars in Oncology. 2007;34(1):51–6.