Most Merkel cell carcinomas (often abbreviated as MCC) are diagnosed when, for example, a skin biopsy (tissue sampling) is performed to rule out other forms of skin cancer caused by the sun, or when a suspected cyst has been removed.
As Merkel cell carcinoma is rare, in most cases the diagnosis comes as a surprise to both the doctor and the patient. Patients go to their doctor with an altered and enlarging area of skin.
Merkel cell carcinoma is diagnosed by means of a skin biopsy (taking a tissue sample), which is then examined under a microscope by a pathologist. Common types of biopsies are a punch biopsy (a small part is removed) or a shave biopsy (part of the top of the altered area (lesion) is removed with a scalpel). The pathologist then performs immunohistochemical staining of the biopsy to determine whether a lesion is a Merkel cell carcinoma or a melanoma, for example.
Merkel cell carcinoma cells can migrate from the skin via lymphatic vessels into lymph nodes. If a lymph node feels enlarged, it may contain macrometastases. Sometimes lymph nodes may contain metastases but not be enlarged (micrometastases). The sentinel lymph node is the first lymph node in the drainage area of the lymphatic fluid of a malignant tumor. Sentinel lymph nodes (also known as sentinel lymph nodes) should therefore be removed by surgery (lymphadenectomy) to determine whether metastases are present.
No, although Merkel cell carcinoma usually looks quite inconspicuous on the skin (e.g. like a cyst), it can be easily identified as Merkel cell carcinoma under the microscope. In most cases, the pattern of certain stains and other tests makes the diagnosis of Merkel cell carcinoma quite simple for the pathologist.
CT, X-ray, MRI, bone scintigraphy and PET scans are different types of imaging used to look inside the body. They are used to find cancer metastases inside the body. They are particularly important if the Merkel cell carcinoma has spread to the lymph nodes in order to assess whether metastases have also developed elsewhere
There are several types of treatment for Merkel cell carcinoma, which are used in different situations – also in combination or in succession. There are three main treatments for Merkel cell carcinoma:
The aim of surgical excision is to remove the Merkel cell carcinoma (primary tumor) in such a way that it does not recur in the immediate vicinity or in nearby lymph nodes. The tumor should therefore be excised over a large area with an appropriate safety margin. Unfortunately, a recurrence of Merkel cell carcinoma is possible even after removal with > 2 cm margins. The risk of local recurrence, which varies depending on the stage of cancer, can be significantly reduced by the accompanying use (adjuvant) of radiotherapy.Radiotherapy is the treatment of cancer with ionizing radiation.
Radiotherapy damages the genetic material of cancer cells and prevents their growth. However, radiotherapy also damages the healthy cells in the area of the radiation. Radiotherapy is administered to patients if they are at risk of tumor spread and want to reduce the likelihood of recurrence.
In contrast to radiotherapy (local therapy), chemotherapy fights the cancer throughout the entire body(systemic therapy). Chemotherapy aims to target uncontrollably dividing and rapidly growing cancer cells. However, healthy, rapidly dividing cells are also affected. Patients with metastatic Merkel cell carcinoma may be given chemotherapy, especially if the tumor has spread to distant organs such as the lungs or liver. However, the previous success of various chemotherapies in advanced Merkel cell carcinomas was rather limited and associated with some severe side effects.
Immunotherapy is a way of treating cancer using substances that restore the body’s own immune cells’ ability to recognize and destroy tumour cells.
There are several therapies that can stimulate the immune system. These include, for example, vaccines, genetically modified immune cells and checkpoint inhibitors (anti-PD-1 or anti-PD-L1 antibodies). Tumor cells escape the immune system by activating molecular “brakes” (such as the PD-1 protein) on the surface of the body’s own immune cells. The checkpoint inhibitors cause these brakes to be released and allow the immune cells to function again and fight the tumor.
These drugs may be an option for patients with advanced Merkel cell carcinoma, e.g. with distant metastases or with Merkel cell carcinoma that cannot be surgically removed. Side effects of immunotherapy can affect any organ. If side effects occur, you must contact the doctor treating you. The most common side effects are: Fatigue, gastrointestinal complaints, rash and cough.
Optimal medical care for the treatment of Merkel cell carcinoma can be guaranteed by a team consisting of dermatologists, surgeons, oncologists and radiation oncologists. After your first treatment, you will need to have regular skin and lymph node checks. Visits should take place approximately every one to three months in the first year, every three months in the second year, every six months in the third to fifth year and annually thereafter.
Aftercare scheme Merkel cell carcinoma version for physicians
Aftercare for Merkel cell carcinoma
There is no data to suggest that there is a genetic / familial predisposition to Merkel cell carcinoma.
As UV radiation is probably the main cause of Merkel cell carcinoma, excessive UV exposure should be avoided. This is especially true if you have already been diagnosed with Merkel cell carcinoma.
Senior Attending Physician, Department of Dermatology
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