Paget's disease

Paget's disease is a rare disease that is associated with breast cancer. It is found in 1 or 2 out of every 100 breast cancers (1 to 2%).

Paget's disease starts in the nipple or in the area of darker skin surrounding it (the areola). It usually first appears as a red, scaly rash of the skin over the nipple and areola. It can be itchy. If it isn't treated, or if you scratch it, it can bleed, ulcerate and may scab over. It looks very similar to other skin conditions such as psoriasis or eczema. It is sometimes diagnosed quite late, and this may be because it is often first treated as eczema, before any cancer tests are done.

Paget's disease is diagnosed from a biopsy. Your breast surgeon will take a sample of the affected skin tissue (a biopsy) from the nipple and send it to be examined under a microscope. If the biopsy shows Paget's disease, you will then have a mammogram. In many cases, Paget's disease is a sign that there is a breast cancer in the breast tissues behind the nipple. About half the women diagnosed with Paget's disease have a lump behind the nipple. In 9 out of 10 cases, this is an invasive breast cancer.

An invasive breast cancer is present in about 4 out of 10 women with Paget's disease who have no lump. But most women with no lump have carcinoma in situ. This means there are cancer cells in the biopsy, but they are completely contained within the lining of the breast ducts or lobes. This is not an invasive breast cancer and so there is no chance that the cancer cells have spread. If left untreated, a carcinoma in situ can go on to develop into an invasive cancer, so if you have carcinoma in situ, your doctor will offer you regular monitoring.

Generally, the treatment for Paget's disease is much the same as for any other breast cancer. You will have surgery to remove either the whole breast or just the affected area. Further treatment depends on whether your results show that you have an invasive breast cancer, or not.

If you are found to have an invasive breast cancer, you may have one of the following treatments after surgery or you may have a combination

• Radiotherapy
• Chemotherapy
• Hormone therapy
• Biological therapy

The exact choice of treatment will depend on the results of your surgery.

Removal of the whole breast (mastectomy) may be the only option if you have a large area affected by Paget's or there is an area of invasive breast cancer behind the nipple. With a cancer in the central area of the breast, your surgeon may not be able to leave you with a good breast shape if you have surgery just to remove the cancer and surrounding tissue. You may get a better appearance if you have the whole breast removed and then have breast reconstruction. For some women, it is possible to just have the area containing the cancer removed, together with a border of healthy tissue. This is followed by a course of radiotherapy to the rest of the breast.

When you have your surgery, the surgeon will take out some of the lymph nodes under your arm. In women who have Paget's with a definite lump, about 66 out of 100 have cancer in the lymph nodes. But in women who have Paget's without a lump, only about 8 out of 100 have cancer in the lymph nodes.

If your breast cancer cells have oestrogen receptors your doctor will probably suggest that you have treatment with hormone therapy. This reduces the risk of the cancer coming back in the same breast. It also reduces the chance of getting a new cancer in the other breast.

Your doctor may suggest further treatment with chemotherapy if there is a significant risk that the cancer may come back. They may suggest this if

• Cancer cells were found in your lymph nodes
• You had a large breast tumour
• Your cancer cells were high grade (grade 3)

Giving chemotherapy helps to lower the risk of the cancer coming back in the future.

In women who have Paget's disease but no breast lump, mastectomy is still the most commonly used treatment even if there is no invasive breast cancer. This is because the cells are abnormal and could develop into an invasive breast cancer if not treated. Your surgeon will remove some lymph nodes to check for signs of cancer. In 9 out of 10 women, there is no sign of cancer in the lymph nodes. But it is best to make sure. In most cases, the surgery will be all the treatment you need.

If the area of abnormal cells is not too large, you may be able to have just the Paget's removed, along with a border of healthy tissue around it. Your doctor is likely to advise that you have radiotherapy after your surgery. Without it, there is quite a high risk that the Paget's will come back. Your surgeon will check your lymph nodes to make sure they don't contain cancer cells.