Bowen's disease, which is also called 'squamous cell carcinoma in situ' (SCC in situ), is a form of skin cancer. The term "in situ" added on the end tells us that this is a surface form of skin cancer. "Invasive" squamous cell carcinomas are the type that grow inward and may spread. SCC in situ is also known as Bowen's disease after the doctor who first described it almost 100 years ago.
SCC in situ is usually a red, scaly patch. It tends to be seen on areas frequently exposed to the sun. Some itch, crust or ooze, but most have no particular feeling. SCC in situ may be mistaken for rashes, eczema, fungus or psoriasis. Sometimes they are brown and look like a keratosis or a melanoma. Because of this, a biopsy must usually be done to confirm the diagnosis.
Like other forms of skin cancer, SCC in situ is mainly caused by chronic sun exposure and aging. There are two other less important causes which are unique to SCC in situ. The wart virus that causes cervical cancer (HPV 16) is often found to be infecting SCC in situ. It is thought that infection with this virus is one of the reasons why two people may have the same amount of sun damage, but only one keeps getting skin cancers. The other factor that causes SCC in situ is arsenic, the same poison made famous by the play "Arsenic and Old Lace" and the Russian villain Rasputin. Arsenic contaminated some old water wells, and also many years ago was used in some medical elixirs. People with mild Arsenic poisoning didn't die, but tend to develop cancers, both of the skin and internally. For a time it was thought that SCC in situ was a sign that cancer was going to develop internally, until it was discovered that was a false impression caused by arsenic poisoning.
The simplest and most common treatment for smaller SCC in situ is surgical excision. The standard practice is to remove about a quarter inch beyond the edge of the cancer. Larger ones can also be excised, but Mohs surgery may be needed. It offers the highest cure rate of all treatment methods.
For those not up to surgery, there are some choices. SCC in situ can be burned off by several methods. These are "curettage and electrodesiccation", liquid nitrogen cryotherapy and laser destruction. These heal with similar scars.
X-ray or grenz ray radiation can be given to poor surgical candidates or patients with multiple sites. This is very expensive and requires multiple visits to the hospital. 5-Fluorouracil cream applied for 1 to 3 months will often work, but leaves an uncomfortable raw area during that time. Imiquimod cream can also be used to treat Bowen’s, with up to a two to three month treatment period required.
The latest treatment approved by the FDA but not yet in common use, is photodynamic therapy (PDT). PDT is an alternative way to "burn off" SCC in situ using a drug that is absorbed only by cancer cells. A bright light is then applies causing the release of toxins and destruction of the tumor.
If you have had an SCC in situ, you have a higher risk of other skin cancers. For this reason, you will need a regular skin exam by a dermatologist. Untreated, SCC in situ grows larger over time and may spread out to be several inches. 5% of SCC in situ will eventually develop into invasive squamous cell carcinoma if not treated.
The dermatologist based on his experience, expertise and analysis of your personal situation is the one best equipped to decide your personal treatment plan.
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