Squamous Cell Carcinoma in Situ, also known as Bowen's Disease, occurs when there's a growth of cancerous cells strictly on the skin's outer layer, which is called the squamous cell skin. It's an easily curable, early form of cancer.
Doctors like to keep an eye on it because, while the condition is not serious, it can rarely progress into full-blown Squamous Cell Carcinoma, which is an invasive type of skin cancer that spreads to the skin's deeper levels. This latter type of carcinoma occurs in about 3% to 5% of cases, and they tend to be undiagnosed.
It's not infectious or contagious, and it's not connected to any allergies. It tends to occur in people with fair complexion, whose skin is prone to sunburns. Because the colour of the skin can be passed on from one generation to the next, the disease may run in the family, but it is not a hereditary condition, per se.
It is believed that Bowens Disease is brought on by long-term exposure to sunlight. It's also prevalent among people receiving immunosuppressive treatments, and it has been connected with radiotherapy, long-term arsenic intake and the human papillomavirus, which causes genital warts to appear.
Its inception usually consists of a persistent patch of scaly red skin about 1 to 3 diameters in size, which spreads slowly. Exposed skin is usually the most affected, with one or several patches occasionally spreading to a few centimetres across on the face, neck, scalp, hands and legs. It can be mistaken for psoriasis, eczema or other skin conditions, which is why having a biopsy is advised.
If a lump or an ulcer develops on top of the patch, this could indicate an invasive form of squamous cell carcinoma. Bleeding also rings alarm bells.
Bowens Disease doesn't usually cause any symptoms. Other than slight discomfort when the skin catches on clothing as you put it on, take it off or brush it against the skin, you shouldn't be aware of any pain.
It's prevalent in women over 70 years of age with fair skin that is exposed to sunlight often. The Bowens Disease patch usually appears on elderly women's lower leg, but it can occur in men as well, and on nearly every part of the body. When it affects the male penis, it's called Bowenoid papilosis, and it looks like a brown patch in the groin area.
Given the fact that it's localised on the skin's surface, Bowens Disease can't be cured as such, but the patches can be removed so that there is virtually no trace of it left. The GP may recommend that you monitor the skin patch, but not intervene in any way. Still, when any form of treatment is recommended, it will usually come with a high cure rate.
Depending on the size, thickness, number, condition and location of the skin patch, one of the following methods can be used to remove the patch:
A skilled medical practitioner will cut out the skin patch, if it's not very large. The area round the patch will be cut under local anaesthetic, and the skin will then be sewn up back into place. This type of surgery will leave a scar.
Liquid nitrogen freeze is a simple procedure that can be carried out at a GP practice either over the course of several sessions or in one fell swoop. You can expect some redness, swelling, crusting and/or blistering afterwards, and healing may take several days.
During curettage, the outer layer on the patch of skin is scraped off after anaesthetising the patient. Then heat is applied to stop the bleeding and help seal the wound. When healed, the area will look like a scab that eventually falls off.
The active ingredient 5-fluorouracil in the 5-FU (chemotherapy) cream destroys abnormal skin cells and leaves the healthy ones intact. As it attacks unhealthy cells, it causes the skin to swell up and turn red, but the inflammation will heal at the end of the course of treatment.
Imiquimod is another cream used to remove abnormal skin cells due to Bowens Disease, but it works by triggering a reaction that makes immune cells attack them. It also causes the skin to become inflamed.
This technique involves shining beams of light of a specific wavelength onto the patch of skin, which has previously been rubbed with light-sensitive cream, and it can be a painful procedure. There will be a 4-6 hour lapse between the moment the cream is applied and the time the laser is directed at the skin, and each laser treatment session can last for up to 45 minutes. The resulting inflammation can last a few days, during which time it should not be exposed to sunlight.
These therapies also involve sending beams of radiation to the patch of skin. Lower leg areas, where the skin is fragile and tight, can't be treated using radiotherapy. Unfortunately, there are many cases of Bowens Disease where the affected area is on the lower legs.
After having any of the treatments described above, you may need follow-up GP appointments.
After you've removed the affected skin area, Bowens Disease patches can re-appear anywhere on the body. Check the skin as often as possible for signs of recurrence. To prevent it, wear UV-protective sunglasses and a hat, and cover your body from head to toe at all times.
Avoid direct sunlight around noon and buy sunscreen with 4 or 5 UVA stars and an SPF over 30. Apply it as specified by the manufacturer, after each swim and no earlier than 30 minutes before each sunbathing session.
If you have a red patch of skin and you don't know what caused it, it is recommended that you see your GP. They may determine the cause directly and diagnose the condition, or refer you to a dermatologist.