What is it?
Vulval intraepithelial neoplasia (VIN) is a condition where there are pre-cancerous cells in the skin of the vulva. Before discussing VIN it is important to remember that skin is divided into three layers: epidermis, dermis and the fatty layers beneath. The epidermis or top layer is less than one millimetre thick and is constantly being shed. Cells from the bottom layer develop and mature and slowly migrate to the top layer where they are shed.
It takes about 120 days for each individual cell to undergo this process. Beneath the epidermis is the dermis, separated by the basement membrane — this acts as a landmark between the two layers. The dermis is much thicker and contains hair follicles, glands (which make skin greasy) and structures which detect sensations such as temperature changes, touch and pressure. Beneath the dermis is the fatty layer which improves body insulation and contains the main blood vessels which supply oxygen to the upper layers.
In VIN, the pre-cancer cells are located within the epidermis or the very top layer and are only a millimetre or so thick. The abnormal cells do not penetrate deep down into the dermis so as a consequence, it is easy to see on the surface of the skin with the naked eye the affected areas. We use the word pre-cancer, NOT because the cells are cancerous or you have cancer, but because the cells MAY (or MAY NOT) develop into cancer over a period of years. The exact relationship between VIN and vulval cancer remains unknown because so few studies have been carried out.
Generally VIN is divided into three stages — I, II or III — depending on how abnormal the cells are. VIN III is the commonest presentation among women and this means that the abnormal cells are present throughout the epithelium (remember it is only a millimetre thick!). In VIN I only a third of the cells in the epithelium are abnormal, whereas in VIN II, two thirds of the cells in the epithelium are abnormal.
What are the symptoms?
The symptoms do vary from woman to woman. Some have no symptoms and the area of VIN is noticed on a routine visit to the doctor. Other women complain of vulval pain or itching which can be quite severe. Others have irritation or painful sex. Some women even notice a lump or thickening of the vulval skin.
What do you find on examination?
Again, like the symptoms, this is variable among different women. Some women notice thickening or hardening of the skin and others have splitting or breakdown of the skin. Some women feel there is nothing wrong with the skin.
What investigations should be done?
VIN is diagnosed by a vulval biopsy where usually a small pea-sized amount of skin is removed from the affected area. Sometimes two or three biopsies are required. The procedure may be carried out under local anaesthetic in the clinic or your doctor may suggest that you come into hospital to have a biopsy removed under general anaesthetic.
A biopsy is essential so that the pathologists can see down the microscope to make sure the area is VIN (and not other skin conditions) and also to see exactly what degree of abnormal cells there are.
What causes it?
This remains unknown. There do appear to be two age groups who get VIN: women in their 60s to 70s and women in their 30s to 40s. In women in their 30s and 40s, VIN does appear to be associated with the family of ‘wart’ viruses (human papilloma viruses) which can cause change in the appearance of the cells down the microscope causing VIN to develop. VIN is noticed to be more common among women who smoke, but whether there is a direct relationship remains unknown.
How common is it?
This remains unknown. However, most women are seen by a gynaecologist with a special interest in the condition and as a result many women are ‘centred’ around one or two doctors in a region. It is generally felt that more and more women are being diagnosed with VIN. This is either because the disease is more common or because more women are being accurately diagnosed.
How is it treated?
There is not one type of treatment to suit all women with VIN and the treatment offered to you should be tailored to suit your needs. You will obviously have to discuss this with your doctor. The type of treatment will depend on several factors including one or more of the following:
- Whether your symptoms are bad
- Where the affected area is on the vulva
- How large the affected area is
- How fit you are for treatment
It is important to remember that not all doctors practise the different treatments mentioned below and different doctors have different experiences of the condition.
Take a ‘wait and see’ approach
Many women with VIN do not have any treatment at all and are simply kept under review at the clinic on a six-monthly or annual basis. This treatment is often practised for women with large areas of VIN and in women who have no symptoms. If you are pregnant this may be an option.
Removal of the area has advantages and disadvantages. Removing the area under anaesthetic will hopefully cure localised areas that cause symptoms. Also it may be necessary to remove some of the vulval skin so that it can be examined under the microscope to exclude cancer development. The disadvantages relate to having the surgery and recovery from the skin removal. For very large areas that need removal there can be distortion of the vulval anatomy and shape, but many areas of VIN that are removed heal without any serious scarring. Ask the surgeon if you have any concerns.
Under general anaesthetic some doctors use the laser to remove the areas of VIN. The advantage of using the laser is that it destroys the very superficial skin layer (epidermis and upper dermis) without scarring or loss of anatomy of the vulva. Its disadvantages relate to recovery post-operatively where good pain relief is initially needed. Sometimes with very large areas, the procedure is done in two stages.
The great difficulty with managing VIN is that following treatment, VIN can recur. As consequence many women will be put on long term, sometimes lifetime, follow-up with a doctor. This procedure is largely abandoned now as the recurrence rates after treatment are high.
Imiquimod cream uses the immune system to attack the areas of VIN. This means it uses the body’s natural defences to kill the pre-cancer cells in the skin. It does this by releasing a number of chemicals called cytokines. The main advantage of Imiquimod cream is that it will not cause scarring so has the advantage of better cosmetic results and you can put it on yourself at home. The disadvantages are that nearly all patients notice a burning sensation when applying the cream which occaisionally can interupt treatment and the response rate of the VIN to treatment is around 60%.
VIN and vulval cancer
Vulval cancer is an uncommon cancer, with only around 1,000 cases diagnosed in the UK each year. Although VIN is regarded as a precancerous condition, up to 20 per cent of women diagnosed initially with VIN will also have an underlying cancer. If VIN is untreated the risk of vulval cancer developing is believed to be very high. With treatment, however, the subsequent risks of VIN patients developing cancer are around 3 to 5 per cent, so close follow-up is important.
What can I do?
Keep follow-up appointments with doctors. Although these visits can generate a lot of anxiety, regular follow-up will hopefully ensure that the VIN remains under control.
If you do have symptoms, then discuss the creams that you can apply with your doctor. Avoid inappropriate antifungals and practise good hygiene.
Smoking has been referred to as a risk factor for VIN. Stopping smoking may make a difference.
- The Association for Lichen Sclerosus and Vulval Health gives information on a support group for VIN. Details of how to apply to join the group are on their website.
- Facebook users also have the option of joining the Vulval Intraepithelial Neoplasia (VIN) UK Support Group.