What is Bowen's disease?|
Bowen’s disease is a carcinoma (cancer) of the squamous cells of the upper (epidermal) layer of the skin. It is one of a number of non-melanoma skin cancers. While it can affect any area of the skin, the face, hands, genital region, trunk and lower legs are commonly affected. Single lesions are most common, although they occasionally occur at multiple sites in the same individual. The lesions associated with Bowen’s disease develop very slowly and, in most cases (approximately 95%), remain benign. That is, they only rarely develop into invasive, malignant tumours or seed malignant tumours to other parts of the body.
What causes Bowen's disease?
The specific cause of the condition is unknown, but its development has been associated with the following factors:
- -chronic sun damage (this cannot be the only cause, because areas of the body which do not receive direct sunlight (normally) are prone to Bowen’s disease)
- -arsenic ingestion (from arsenic containing insecticides, for example)
- -radiation therapy (which, ironically, is sometimes used as a treatment - see below)
- -infection with human papillomaviruses (particularly in those lesions associated with the genital region)
What are the symptoms?
The skin lesions of Bowen’s disease commonly present as flat, slight raised patches of red scaly skin with well defined and irregularly shaped edges, occasionally with a pigmented appearance. The lesions are essentially asymptomatic. For this reason, along with the fact they develop so slowly, mean they can remain unnoticed for months or years. Ulceration may occur, this often being a sign that the tumour has become invasive. Where the anal region is involved, patients may present with bleeding, a burning sensation and anal discharge.
The condition is generally rare, although it is comparatively more common in sunny countries. Of those people who develop the disease, 66-79% are females, with the majority being over 40 years of age. As a generalisation, therefore, it is a condition of elderly females. Whether the higher prevalence in females represents a genetic predisposition or a differential exposure to risk factors is not known.
Diagnosis of Bowen’s disease may not occur for months or years following development of a lesion because of the relative lack of symptoms and slow growth rate. It is perhaps not surprising, therefore, that 25-40% of patients with anal involvement are coincidentally identified during rectal examination for haemorrhoids. The disease can be differentiated from other causes of red, scaly skin lesions (psoriasis, for example) by the lack of effect of steroid treatment on Bowen’s disease. The diagnosis can be confirmed by taking a tissue sample from the affected area (biopsy), and examining microscopically for characteristic changes in the squamous cells.
Management and treatment
Treatment is usually successful at curing the disease, recurrences being relatively uncommon (success rates for most treatments are generally quoted in the 90-95% range). However, the issue of follow-up of patients after treatment remains an important one, in case of recurrence. A study by Holt in 1988 showed that non-melatonin skin cancers (including Bowen’s disease) treated with cryotherapy (see below) tend to recur, if at all, with in two years of the initial treatment. The critical follow-up period for Bowen’s disease, therefore, has been suggested to be the two years following the initial treatment.
Any further issues of management of the disease generally revolve around complications associated with its treatment. Most of the treatment methods commonly used have associated with them as a consequence some aspect of wound healing. This itself usually only bec