Find out about Merkel cell carcinoma. This is a rare type of neuroendocrine tumour.

Merkel cell cancers are a rare type of skin cancer. They develop in Merkel cells which are in the top layer of the skin. These cells are near the nerve endings and they help us respond to touch. Merkel cell cancers are a rare type of neuroendocrine tumour.

Causes

As with other types of skin cancer long term exposure to sunlight increases your risk of getting Merkel cell cancer. Other factors that can increase your risk include:

• ultraviolet light treatment, PUVA (psoralen ultra violet treatment), for skin conditions such as psoriasis
• conditions or treatments that can weaken your immune system, including people who have had an organ transplant and people who have AIDS.

Symptoms

Merkel cell cancer usually appears as a lump on the skin. The lumps are usually bluish red in colour and about 1 to 5 cm across, although they are sometimes larger. The skin over them is not usually broken (ulcerated). They are most often found in the areas of the body that get the most direct sun such as the:

• head
• neck
• arms
• legs

Unfortunately, unlike most other types of skin cancer, Merkel cell cancer can grow very quickly. It can often spread to other parts of the body such as the lymph nodes, lungs, liver or bone.

Tests and staging

Most people who are diagnosed with Merkel cell carcinoma will need to have further tests to see if the cancer has spread. You might have a:

• chest x-ray
• ultrasound scan
• CT scan, PET-CT scan or MRI scan

When somebody is diagnosed with any type of cancer, the cancer is staged. This means finding out exactly how big or deep the cancer is. Also if it has spread to any of the nearby lymph nodes or to other parts of the body.

Staging is a very important process as it helps doctors to decide on the best treatment. 

Treatment

The main treatment is surgery to remove it if the cancer is only in the surface layers of skin (localised). This is a rare cancer so treatment should be carried out at a specialist skin cancer centre. The team of doctors should include a:

• skin cancer specialist (dermatologist)
• plastic surgeon
• clinical oncologist

They will aim to remove all of the cancer cells and you might hear them use the term clear margins. This means that all the signs of the cancer have been removed. To make sure of this, the surgeon will send the tissue that he or she has removed to the laboratory. A specialist will examine it very closely to make sure there is a clear margin of healthy tissue around all the cancerous tissue that has been removed.

Your doctor will also be able to explain whether or not you need to have any lymph nodes removed and whether you will need any further treatment or scans afterwards.

It is quite common for specialists to recommend radiotherapy after surgery. The aim of the radiotherapy is to kill off any cancer cells that may have been left behind, but are too small to be seen. Sometimes, if surgery is very difficult or the lump is very large, radiotherapy might be used on its own. This usually works very well.

Treatment for cancer that has spread

Merkel cell carcinoma can spread into the skin as lumps. This can be in the area it started or into the local lymph nodes. Any spread of the cancer can be treated by surgery, with or without radiotherapy. 

Isolated limb perfusion (ILP) might also work very well. In ILP the blood supply of the affected limb is isolated (blocked off). Then oxygen and chemotherapy are put into the limb. After the oxygen and chemotherapy have circulated, the blood supply is returned to normal. Isolated limb infusion (ILI) is a newer version of ILP. No oxygen is used. This means ILI takes less time to do. Some studies have found that patients have less problems after ILI.

Chemotherapy can usually control Merkel cell cancers that have spread to other parts of the body. The drugs you might have are carboplatin or cisplatin with etoposide. The chemotherapy treatment might control the cancer for a while, but unfortunately it is not a cure.

Coping

Coping with a diagnosis of a rare cancer can be especially difficult, both practically and emotionally. Being well informed about your cancer and its treatment can make it easier to make decisions and cope with what happens.

Talking to other people

Talking to other people who have the same thing can also help.

Our discussion forum Cancer Chat is a place for anyone affected by cancer. You can share experiences, stories and information with other people who know what you are going through.

The Rare Cancer Alliance offer support and information to people affected by rare cancers.