Bowen's disease = intraepidermal carcinoma = IEC = Squamous cell carcinoma in-situ
Bowen’s disease is a precancerous lesion. In-situ refers to the fact that the disease has not penetrated the basement membrane. Once this occurs, the lesion is a squamous cell carcinoma a full blown skin cancer.
Bowen’s disease typically presents as an asymptomatic, slow growing, sharply-demarcated, scaly erythematous [red, pink, salmon coloured] patch or plaque. The border may be irregular.
The surface may be flat, scaly, crusted, eroded, ulcerated, velvety or verrucous [warty]. Because of its asymptomatic nature, lesions may become very large by the time of presentation.
BD occurs most commonly in later life and most patients aged over 60.
Although BD can occur just about anywhere, common sites for presentation are the lower limbs and head and neck. Women are affected more than men and in approx 3% of cases Bowen’s disease transforms to SCC and about 1/3 of these will metastasise [spread to other parts of the body].
TREATMENT for Bowen’s disease
For Bowen’s disease there is no right or wrong way to treat. Individualizing to the patient and lesion are the key.
1. No treatment
Given that only 3% of Bowen’s disease progresses to invasive squamous cell carcinoma then no treatment could be considered an option in some elderly frail patients with co-morbidity or with a limited lifespan. In other words, it may be kinder to do nothing.
Lesions especially suitable for no treatment are those that are thin and considered unlikely to progress to squamous cell carcinoma and those located on sites where healing is a problem.
2. Fluorouracil [5FU 5%cream = Efudix]
Several open studies have shown 5FU to be efficacious in clearing BD. Cure rates of 66-93% have been reported.
The highest cure rates are achieved when Efudix is applied once or twice daily for 6-16 weeks and included a margin around the lesion
There is a lot of variability in the way Efudix is prescribed with some Physicians recommending it twice a day, every day, others every other night or twice weekly and for differing lengths of treatment.
Efudix sometimes produces irritation, inflammation, erosions and ulcerations, so less aggressive regimens have been suggested. But these regimens give higher recurrence rates.
The benefits of cryotherapy should be balanced against the risk of creating an ulcer that may take a long time to heal (e.g. BD on lower leg of elderly female).
Is an excellent treatment for Bowen’s disease. Its a simple, quick and inexpensive procedure and high cure rates have been quoted.
Recurrences may be attributable to the experience of the surgeon or to repopulation by Bowen’s disease cells from hair follicles, sweat gland etc.
Generally cure rates are similar to other treatments with some advantages. A report in the British Journal of Dermatology a few years ago showed the superiority of curettage and cautery over cryotherapy in the treatment of Bowen’s disease especially lower leg.
In selected cases curettage and cautery can give shorter healing times:
Lower recurrence rates than cryotherapy
For well defined small lesions where excision and primary closure can be performed surgery is a good option
But one has to be careful as lesions on the lower leg can be large and the skin is poorly vascularised skin where healing can be a problem one risks dehiscence or necrosis or skin grafting adding to morbidity
The recurrence rates for Bowen’s disease removed by simple excision is between = 5 –20% and may be related to subclinical extensions
Mohs micrographic surgery – excellent for large lesions, or where tissue sparing is vital eg younger patients but expensive and time consuming. Recurrence rates are lower with Mohs micrographic surgery. Generally not needed for Bowen’s disease except at critical sites or after recurrences.
The problem with destructive surgical techniques such as Curettage and cautery, cryotherapy and Ablative lasers is that tissue is unavailable to confirm complete removal. Results are generally good but in the case of lasers to require special equipment and trained staff
Bowen’s disease is reported to be radiosensitive, various forms of ionising radiation have been used and cure rates = 89-100%
Management of large and multiple lesions
Especially in elderly, infirm or those on anticoagulants [blood thinners]
Inadequate treatment at deep margin leads to recurrences
Problem with healing – especially lower leg
Poor healing associated with diameter of radiotherapy field, dosage and energy of radiation, patient age >90
Photodynamic therapy [PDT]
In the last decade PDT has shown considerable promise for the treatment of premalignant skin conditions such as Bowen’s disease.
A topical photosensitiser precusor is applied to a lesion this is preferentially taken up by tumour cells and converted to a potent photosensitiser the lesion is then irradiated with light activating the photosensitiser and the tumour is destroyed.
Several studies have shown topical PDT to be effective in the initial clearance of Bowen’s disease.
Cosmetic results are usually excellent consider it for:
large lesions, on poorly vascularized skin
For those patients unsuitable for surgery
But it is time consuming
repeated treatments can be necessary
This is an immune response modifier, rather than inhibiting and suppressing the immune system it stimulates it. Demonstrates potent antiviral, anti-tumour and immunoregulatory properties.
In one study, 16 patients with Bowen’s disease applied Imiquimod o.d. 16 weeks. Lesions were up to 5.5 cm in diameter. 15 legs 1 shoulder 6 weeks after treatment 14/15 patient’s biopsies showed no residual tumour. Patients did experience local skin reactions similar to 5-fluorouracil 6 patients stopped early because of local skin reactions
Ablative Laser [CO2, erb:YAG laser]
This can be useful for selected Bowen’s disease.