Bowen's disease = intraepidermal carcinoma = IEC = Squamous cell carcinoma in-situ

Read our Bowen’s disease article in the BMJ 2020

The term squamous cell carcinoma in situ (SCC in situ) perhaps more accurately reflects what Bowen’s disease is.

Bowen’s disease shows precancerous changes throughout the whole thickness of the epidermis

2014 Guidelines

Bowen’s disease was described in 1912 by Professer JT Bowen

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 are 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

It has traditionally been thought that about 3-5% of Bowen’s disease transformed to SCC. However recent data suggests that this might be as high as 16% (Varma S. Reply to: Frequency of squamous cell carcinoma in situ (SCCIS) and SCC in re-excisions of biopsy-proven cutaneous SCCIS. Br J Dermatol 2018; 179: 223-224.). About 1/3 of these SCC are thought to metastasise (spread to other parts of the body)

Treatments for Bowen’s disease

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

5 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.

Cryotherapy

This is a quick and simple method to treat IEC with usually excellent success rates for small IECs in sites that heal well. 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).

Curettage

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

Surgery

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.

The problem c destructive surgical techniques such as Curettage and cautery, cryo and Ablative lasers is that no tissue is available  to confirm complete removal. Results are generally good but in the case of lasers to require special eqiuipment and trained staff

Radiotherapy

Bowen’s disease is reported to be radiosensitive

Various forms of ionising radiation have been used

Cure rates = 89-100%

Advantages

Disadvantages

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.

Imiquimod (Aldara) [not licensed for IEC]

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.

Mohs micrographic surgery

I have removed several IEC/ Bowen's disease of the nail or finger with Mohs surgery. It is important to establish that the lesion is not a full blown SCC. Benefits of Mohs include tissue sparing and complete IEC removal.